JP2010223646A - Wavelength spectrum detection method - Google Patents

Wavelength spectrum detection method Download PDF

Info

Publication number
JP2010223646A
JP2010223646A JP2009069347A JP2009069347A JP2010223646A JP 2010223646 A JP2010223646 A JP 2010223646A JP 2009069347 A JP2009069347 A JP 2009069347A JP 2009069347 A JP2009069347 A JP 2009069347A JP 2010223646 A JP2010223646 A JP 2010223646A
Authority
JP
Japan
Prior art keywords
light
wavelength
photocurrent
photodiode
value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2009069347A
Other languages
Japanese (ja)
Other versions
JP5445906B2 (en
Inventor
Masahiro Akiyama
正弘 秋山
Kazuaki Sawada
和明 澤田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyohashi University of Technology NUC
Institute of National Colleges of Technologies Japan
Original Assignee
Toyohashi University of Technology NUC
Institute of National Colleges of Technologies Japan
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyohashi University of Technology NUC, Institute of National Colleges of Technologies Japan filed Critical Toyohashi University of Technology NUC
Priority to JP2009069347A priority Critical patent/JP5445906B2/en
Publication of JP2010223646A publication Critical patent/JP2010223646A/en
Application granted granted Critical
Publication of JP5445906B2 publication Critical patent/JP5445906B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Landscapes

  • Light Receiving Elements (AREA)
  • Spectrometry And Color Measurement (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To propose a wavelength spectrum detection method using a photodiode for achieving a compact and portable device that does not restrict its installation location and can operate at a low voltage. <P>SOLUTION: In this method for detecting the wavelength spectrum of optional light, the photodiode as a photoelectric conversion element is used, and a photocurrent value (or voltage value resulting from photocurrent) acquired from the photodiode is used, and the photocurrent value when light for comparison whose wavelength and photocurrent value are known in advance is made to enter the photodiode is detected. The wavelength spectrum of the optional light is detected based on a numerical formula 2 and the photocurrent value when the optional light is made to enter the photodiode. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

この発明は、波長スペクトルを検出する方法に関し、より詳細には、フォトダイオードの光電流値に基づいて波長スペクトルを検出するフォトダイオードを用いた波長スペクトル検出方法に関する。   The present invention relates to a method for detecting a wavelength spectrum, and more particularly to a wavelength spectrum detecting method using a photodiode that detects a wavelength spectrum based on a photocurrent value of the photodiode.

これまでに、波長スペクトル測定をするための方法として「アバランシェフォトダイオードを用いた波長スペクトル検出方法」がある（特許文献１参照）。   To date, there is a “wavelength spectrum detection method using an avalanche photodiode” as a method for measuring a wavelength spectrum (see Patent Document 1).

上記の「アバランシェフォトダイオードを用いた波長スペクトル検出方法」は任意の光の波長スペクトルを検出する方法であって、アバランシェフォトダイオードの増倍率を検出する増倍率検出回路を用いて、アバランシェフォトダイオードに、予め波長が判明している比較用の光を入射させたときの増倍率を検出し、アバランシェフォトダイオードに前記任意の光を入射させたときの増倍率を、増倍率検出回路を用いて検出し、数式１に基づいて、前記任意の光の波長スペクトルを検出することを特徴とするアバランシェフォトダイオードを用いた波長スペクトル検出方法である。なお、Anは波長λnの光比率（含有率）。ｎは、1以上の整数。X[λn，Vn]はアバランシェフォトダイオード（APD）に「逆バイアス電圧Vnを印加し、波長λnの光を入れた場合」の増倍率。M(n)はAPDに「逆バイアス電圧Vnを印加し、任意の光（波長スペクトルを求めたい光）を入れた場合」の増倍率である。
The above-mentioned “wavelength spectrum detection method using an avalanche photodiode” is a method for detecting a wavelength spectrum of arbitrary light, and a gain detection circuit for detecting a multiplication factor of an avalanche photodiode is used to detect an avalanche photodiode. Detects the multiplication factor when a comparative light whose wavelength is known in advance is incident, and detects the multiplication factor when the arbitrary light is incident on the avalanche photodiode using a multiplication factor detection circuit Then, the wavelength spectrum detection method using an avalanche photodiode is characterized in that the wavelength spectrum of the arbitrary light is detected based on Formula 1. An is the light ratio (content ratio) of wavelength λn. n is an integer of 1 or more. X [λn, Vn] is the multiplication factor of “when reverse bias voltage Vn is applied and light of wavelength λn is applied” to the avalanche photodiode (APD). M (n) is a multiplication factor of “when reverse bias voltage Vn is applied and arbitrary light (light whose wavelength spectrum is desired to be obtained) is input” to the APD.

特開２００８−２４１５７８（第３頁、従来の技術）JP2008-241578 (page 3, conventional technology)

しかし、上記した光スペクトル検出方法は大きな印加電圧を必要とするため、消費電力が大きくなることに問題があった。   However, since the above optical spectrum detection method requires a large applied voltage, there is a problem that power consumption increases.

そこで、本発明は上記課題を解決するためになされ、その目的とするところは、低電圧動作が可能となる、フォトダイオードを用いた波長スペクトル検出方法を提案することにある。   Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to propose a wavelength spectrum detection method using a photodiode that enables low-voltage operation.

本願の第１発明は、任意の光の波長スペクトルを検出する方法であって、フォトダイオードに予め波長λnのｎ種の比較用の光を入射させたときの光電流値を検出しておき、フォトダイオードに前記任意の光を入射させたときの光電流値を検出し、数式２に基づいて、前記任意の光の各波長λnの光毎の光電流比率を検出することを特徴とするフォトダイオードを用いた波長スペクトル検出方法である。ここで、ｎは２以上の整数、Anは前記任意の光に含まれる各波長λnの光の光電流比率、Imix(Vn)はフォトダイオードに逆バイアス電圧Vnを印加し、前記任意の光を入射させた場合の光電流値、I[λn，Vn]は、逆バイアス電圧V0（V0はV1からVnより大きい電圧）を印加したときにImix(V0)と同じ光電流値になる光量を有する波長λnの前記比較用の光を入射させた場合において、逆バイアス電圧Vnを印加したときの光電流値である。
1st invention of this application is the method of detecting the wavelength spectrum of arbitrary light, Comprising: The photoelectric current value when n types of comparative light of wavelength (lambda) n was previously made incident on a photodiode is detected, A photocurrent value when the arbitrary light is incident on a photodiode is detected, and a photocurrent ratio for each light of each wavelength λn of the arbitrary light is detected based on Formula 2. This is a wavelength spectrum detection method using a diode. Here, n is an integer of 2 or more, An is a photocurrent ratio of light of each wavelength λn included in the arbitrary light, Imix (Vn) is a reverse bias voltage Vn applied to the photodiode, and the arbitrary light is The incident photocurrent value, I [λn, Vn], has an amount of light that has the same photocurrent value as Imix (V0) when a reverse bias voltage V0 (V0 is a voltage greater than V1 to Vn) is applied. This is the photocurrent value when the reverse bias voltage Vn is applied when the comparative light of wavelength λn is incident.

本発明において、上記任意の光がｎ種の波長の光の混合光である場合に確実にスペクトルを検出することができるが、必ずしもｎ種の波長の光の混合光でなくとも、上記任意の光がｎ種の波長の比較用の光の混合光であると仮定して各比較用の光の光電流比率を得ることで、概略のスペクトルを把握することが可能である。また、上記のI[λn，Vn]については、事前に波長λnに対する電圧依存特性を測定してデータベース化しておくことが好ましい。このようにすると、Ｉmixの電圧依存性を測定したとき、当該電圧依存性に合わせて上記電圧V0を選択でき、しかも、これより小さい上記電圧Vnの値を選択することが可能になる。   In the present invention, the spectrum can be reliably detected when the arbitrary light is a mixed light of n kinds of wavelengths, but the arbitrary light is not necessarily a mixed light of light of n kinds of wavelengths. It is possible to grasp the approximate spectrum by obtaining the photocurrent ratio of each comparative light assuming that the light is a mixed light of comparative light having n types of wavelengths. Further, for the above I [λn, Vn], it is preferable to measure the voltage dependence characteristics with respect to the wavelength λn and prepare a database in advance. In this way, when the voltage dependency of Imix is measured, the voltage V0 can be selected in accordance with the voltage dependency, and a value of the voltage Vn smaller than this can be selected.

次に、本願の第２発明は、任意の光の波長スペクトルを検出する方法であって、フォトダイオードに予め波長λnのｎ種の比較用の光を入射させたときの光電流値を検出しておき、フォトダイオードに前記任意の光を入射させたときの光電流値を検出し、数式３に基づいて、前記任意の光の各波長λn毎の光電流比率を検出することを特徴とするフォトダイオードを用いた波長スペクトル検出方法である。ここで、ｎは２以上の整数。Anは各波長光の光電流の混合割合の和が1になると仮定したときの前記任意の光に含まれる各波長λnの光の光電流比率、Imix(Vn-1)はフォトダイオードに逆バイアス電圧Vn-1を印加し、前記任意の光を入れた場合の光電流値、I[λn，Vn-1]は、逆バイアス電圧V0（V0はV1からVnより大きい電圧）を印加したときにImix(V0)と同じ光電流値になる光量を有する波長λnの前記比較用の光を入射させた場合において、逆バイアス電圧Vn-1を印加したときの光電流値である。
Next, the second invention of the present application is a method for detecting a wavelength spectrum of arbitrary light, and detects a photocurrent value when n kinds of comparative light of wavelength λn are previously incident on a photodiode. The photocurrent value when the arbitrary light is incident on the photodiode is detected, and the photocurrent ratio for each wavelength λn of the arbitrary light is detected based on Equation 3. This is a wavelength spectrum detection method using a photodiode. Here, n is an integer of 2 or more. An is the photocurrent ratio of the light of each wavelength λn included in the arbitrary light, assuming that the sum of the mixing ratio of the photocurrent of each wavelength light is 1, and Imix (Vn-1) is the reverse bias to the photodiode When the voltage Vn-1 is applied and the above-mentioned arbitrary light is applied, the photocurrent value, I [λn, Vn-1], is obtained when the reverse bias voltage V0 (V0 is a voltage greater than V1 to Vn) is applied. This is the photocurrent value when the reverse bias voltage Vn-1 is applied in the case where the comparative light having the wavelength λn having the same light amount as that of Imix (V0) is incident.

また、上記第２の発明において、前記光電流比率Anから数式４に基づいて前記任意の光の波長スペクトルを検出することが好ましい。ここで、Xｎは波長λnの光により発生した補正後の光電流の比率（含有率）、Fnは各波長光の光電流の混合割合の和が１になると定義して計算を行った際に生じる誤差を補正する係数である。
In the second aspect of the invention, it is preferable that the wavelength spectrum of the arbitrary light is detected based on Formula 4 from the photocurrent ratio An. Here, Xn is the ratio (content ratio) of the corrected photocurrent generated by the light of wavelength λn, and Fn is calculated when the sum of the photocurrent mixing ratio of each wavelength light is defined as 1. This is a coefficient for correcting an error that occurs.

ここで、上記の補正係数Fnは通常１である。しかし、光量と共に光電変換効率が変化するデバイスを用いる場合（各波長光の光電流の割合の和は1にならない場合）は、あらかじめFnを求めておく必要がある。補正係数の求め方は２つある。１つ目は、各光量、各光電流の比率に対するFnの値を光電変換効率より計算する方法である。2つ目は、各光量、各光電流の比率に対するFnの値を実験より求める方法、すなわち、予め上記電圧V0,Vn毎に理論値と実測値との差に基づいて求めたものである。   Here, the correction coefficient Fn is normally 1. However, when using a device whose photoelectric conversion efficiency varies with the amount of light (when the sum of the ratios of photocurrents of light of different wavelengths is not 1), it is necessary to obtain Fn in advance. There are two ways to obtain the correction coefficient. The first is a method of calculating the value of Fn with respect to the ratio of each light quantity and each photocurrent from the photoelectric conversion efficiency. The second method is to obtain the value of Fn with respect to the ratio of each light quantity and each photocurrent by experiment, that is, based on the difference between the theoretical value and the actual measurement value for each of the voltages V0 and Vn in advance.

本発明にかかるフォトダイオードを用いた波長スペクトル検出方法によれば、低電圧動作の検出装置が実現可能となる。   According to the wavelength spectrum detection method using the photodiode according to the present invention, it is possible to realize a detection device that operates at a low voltage.

フォトダイオード（アモルファスシリコンフォトダイオード）の入射光の波長と光電流値の依存特性を示すグラフである。It is a graph which shows the dependence characteristic of the wavelength of incident light of a photodiode (amorphous silicon photodiode), and a photocurrent value. フォトダイオード（アモルファスシリコンフォトダイオード）の構造を示す断面図である。It is sectional drawing which shows the structure of a photodiode (amorphous silicon photodiode). フォトダイオード（アモルファスシリコンフォトダイオード）への印加電圧を変化させた場合の入射光の波長と光電流値の依存特性を示すグラフである。It is a graph which shows the dependence characteristic of the wavelength and photocurrent value of incident light at the time of changing the applied voltage to a photodiode (amorphous silicon photodiode). 波長a[nm]とb[nm]の光を入射した場合のI（光電流）-V（印加電圧）特性のイメージを示すグラフである。It is a graph which shows the image of I (photocurrent) -V (applied voltage) characteristic at the time of entering the light of wavelength a [nm] and b [nm]. 波長a[nm]とb[nm]の光と混合光を入射した場合のI（光電流）-V（印加電圧）特性のイメージを示すグラフである。It is a graph which shows the image of I (photocurrent) -V (applied voltage) characteristic at the time of entering the light of wavelength a [nm] and b [nm], and mixed light. 自作したa-Si:H PDの暗電流特性を示すグラフである。It is a graph which shows the dark current characteristic of self-made a-Si: HPD. 自作したa-Si:H PDの波長依存特性（波長[nm]-光電流[A]特性）を示すグラフである。It is a graph which shows the wavelength dependence characteristic (wavelength [nm] -photocurrent [A] characteristic) of self-made a-Si: HPD. 測定系（等価回路）を示す回路図である。It is a circuit diagram which shows a measurement system (equivalent circuit). 測定冶具の概観を示す写真である。It is a photograph which shows the outline of a measurement jig. 本実験の条件を対応させたI-V特性を示すグラフである。It is a graph which shows the IV characteristic which matched the conditions of this experiment. 測定より得られた各波長光のI-V特性を示すグラフである。It is a graph which shows the IV characteristic of each wavelength light obtained from the measurement. 測定より得られた混合光のI-V特性を示すグラフである。It is a graph which shows the IV characteristic of the mixed light obtained from the measurement.

フォトダイオード（例えば、アモルファスシリコンフォトダイオード）（以下、単にa-Si PDと称する場合がある）は入射光の波長により光電流値が変化する特徴を持っている。   A photodiode (for example, an amorphous silicon photodiode) (hereinafter sometimes simply referred to as a-Si PD) has a feature that the photocurrent value changes depending on the wavelength of incident light.

図1にフォトダイオード（実際にはアモルファスシリコンフォトダイオード）の入射光の波長と光電流値の依存特性を示す。このときのバイアス電圧は３Ｖである。   Fig. 1 shows the dependence of the incident light wavelength and photocurrent on the photodiode (actually an amorphous silicon photodiode). The bias voltage at this time is 3V.

フォトダイオード（アモルファスシリコンフォトダイオード）にはpin構造を用いる。この構造により、光電流に波長依存特性を持ったフォトダイオード（アモルファスシリコンフォトダイオード）となる。   A pin structure is used for the photodiode (amorphous silicon photodiode). With this structure, a photodiode (amorphous silicon photodiode) having a wavelength dependent characteristic in photocurrent is obtained.

図２にフォトダイオード（アモルファスシリコンフォトダイオード）の具体例を示す。
（詳細は「特開平１１−１０３０８９」を参照。） FIG. 2 shows a specific example of a photodiode (amorphous silicon photodiode).
(For details, see "Japanese Patent Laid-Open No. 11-103089")

フォトダイオード（アモルファスシリコンフォトダイオード）１の構造は、基板用電極２、正孔注入阻止層３、光吸収層４、電子注入阻止層５および透明電極６をこの順序に積層した光電変換素子となる。図２で光入射側は透明電極６側で、この実施例では印加電界は透明電極６側が負で基板用電極２側が正である。   The structure of the photodiode (amorphous silicon photodiode) 1 is a photoelectric conversion element in which a substrate electrode 2, a hole injection blocking layer 3, a light absorption layer 4, an electron injection blocking layer 5 and a transparent electrode 6 are stacked in this order. . In FIG. 2, the light incident side is the transparent electrode 6 side. In this embodiment, the applied electric field is negative on the transparent electrode 6 side and positive on the substrate electrode 2 side.

以下各層の構成作用を順次に説明するが、基板用電極２は、その上の正孔注入阻止層３と電気的に良好な接触（オーミックコンタクト）をする金属電極である。   Hereinafter, the constituent actions of each layer will be described in sequence. The substrate electrode 2 is a metal electrode that makes good electrical contact (ohmic contact) with the hole injection blocking layer 3 thereon.

正孔注入阻止層３は、基板用電極からの光吸収層への正孔の注入を阻止し、この変換装置の暗電流の低減化をはかり、光吸収層に加わる電界を高める作用を有し、具体的にはｎ型の単結晶シリコン層を使用し、さらに特別にはその不純物濃度を１０16〜１０17ｃｍ-3として光吸収層への基板用電極側からの正孔の注入を抑え、低暗電流で波長依存特性のある構造となっている。 The hole injection blocking layer 3 has the function of blocking the injection of holes from the substrate electrode into the light absorption layer, reducing the dark current of the conversion device, and increasing the electric field applied to the light absorption layer. Specifically, an n-type single crystal silicon layer is used, and more specifically, the impurity concentration is set to 10 16 to 10 17 cm −3 to suppress injection of holes from the substrate electrode side into the light absorption layer. It has a structure with low dark current and wavelength-dependent characteristics.

また、光吸収層４は、効率良く光を電荷に変換させるため、膜内の欠陥密度が低く抵抗が高いノンドープ（不純物 が添加されていない）または微量に不純物を導入した水素化非晶質シリコン（ａ‐Ｓｉ：Ｈ）層で構成されている。   In addition, the light absorption layer 4 is non-doped (no impurities are added) with low defect density and high resistance in the film in order to efficiently convert light into electric charges, or hydrogenated amorphous silicon into which impurities are introduced in a trace amount. It is composed of an (a-Si: H) layer.

さらにまた、電子注入阻止層５は、透明電極からの光吸収層への電子の注入を阻止し、この変換装置の暗電流の低減化をはかり、光吸収層に加わる電界を高める 作用を有し、具体的にはｐ型の水素化非結晶材料層（ａ‐ＳｉＣ：Ｈ）を用いている。   Furthermore, the electron injection blocking layer 5 has the function of blocking the injection of electrons from the transparent electrode into the light absorption layer, reducing the dark current of the conversion device, and increasing the electric field applied to the light absorption layer. Specifically, a p-type hydrogenated amorphous material layer (a-SiC: H) is used.

さらにまた、透明電極６は光を透過させる必要があるため、酸化インジウム・錫（ＩＴＯ），ＺｎＯ，ＳｎＯ2 や半透明金属電極を用いる。またさらに暗電流を低減させるために電子注入阻止層に対してショットキ接触となる材料が選択して使用される。 Furthermore, since the transparent electrode 6 needs to transmit light, indium oxide / tin (ITO), ZnO, SnO 2 or a translucent metal electrode is used. In order to further reduce the dark current, a material that makes a Schottky contact with the electron injection blocking layer is selected and used.

ここで、任意の光（波長スペクトルを求めたい光）がフォトダイオード（アモルファスシリコンフォトダイオード）に入射した場合の電流値は、数式５のように定義される。
Here, a current value when arbitrary light (light whose wavelength spectrum is desired to be obtained) is incident on a photodiode (amorphous silicon photodiode) is defined as Equation 5.

また、フォトダイオード（アモルファスシリコンフォトダイオード）は印加電圧によっても電流値が変化する特徴を持っている。図３にフォトダイオード（アモルファスシリコンフォトダイオード）への印加電圧を変化させた場合の入射光の波長と電流値の依存特性を示す。   In addition, a photodiode (amorphous silicon photodiode) has a feature that the current value changes depending on the applied voltage. FIG. 3 shows the dependence characteristics of the wavelength and current value of incident light when the voltage applied to the photodiode (amorphous silicon photodiode) is changed.

ここで、印加電圧をV1からVnに変化させた場合において、任意の光（波長スペクトルを求めたい光）がフォトダイオード（アモルファスシリコンフォトダイオード）に入射した場合の光電流値は、数式６のように表される。
Here, when the applied voltage is changed from V1 to Vn, the photocurrent value when arbitrary light (light whose wavelength spectrum is to be obtained) is incident on the photodiode (amorphous silicon photodiode) is as shown in Equation 6. It is expressed in

数式６を行列に書き換えると数式７のようになる。
When Formula 6 is rewritten into a matrix, Formula 7 is obtained.

ここで、Anは各波長光の光電流の割合の和が１に成るとした定義しているので数式８が成り立つ。
Here, since An defines that the sum of the ratios of the photocurrents of the respective wavelength lights is 1, Equation 8 is established.

数式７のn列目の式を数式８と置き換え整理すると数式９となる。
When the formula in the nth column of Formula 7 is replaced with Formula 8, Formula 9 is obtained.

数式９を波長スペクトル（A1からAn）を求める形に変形すると数式１０（数式３）のようになる。なお、数式７についても数式１０と同様の形式に変換すると、上記の数式２となる。
When Formula 9 is transformed to obtain the wavelength spectrum (A 1 to An ), Formula 10 (Formula 3) is obtained. Note that Equation 7 is also converted to Equation 2 when converted into the same format as Equation 10.

このように、各波長の光による光電流の割合は、数式２若しくは数式１０より求めることができる。ここで、Anは波長λnの光による光電流値の比率（含有率）を示している。また、I[λn，Vn]はフォトダイオード（アモルファスシリコンフォトダイオード）に逆バイアス電圧Vnを印加し、波長λnの光を入れた場合の電流値を表している。またImix(Vn)はフォトダイオード（アモルファスシリコンフォトダイオード）に逆バイアス電圧Vnを印加し、任意の光（波長スペクトルを求めたい光）を入れた場合の電流値を表している。この式より、I[λn，Vn]を予め測定して置けば、「任意の光」の電流値Imix(V1)からImix(Vn)を求めることで、数式２又は数式１０により光電流の混合比（A1からAn）が求められる。この混合比は上記任意の光の波長スペクトルに対応している。ただし、数式１０を用いる場合において光電流比率の誤差を直すには後述する補正係数が必要となる。   Thus, the ratio of the photocurrent by the light of each wavelength can be obtained from Equation 2 or Equation 10. Here, An indicates the ratio (content ratio) of the photocurrent value due to light of wavelength λn. I [λn, Vn] represents a current value when a reverse bias voltage Vn is applied to a photodiode (amorphous silicon photodiode) and light of wavelength λn is applied. Imix (Vn) represents a current value when a reverse bias voltage Vn is applied to a photodiode (amorphous silicon photodiode) and arbitrary light (light whose wavelength spectrum is to be obtained) is input. From this equation, if I [λn, Vn] is measured in advance, the current value Imix (V1) of “arbitrary light” is obtained from the current value Imix (Vn). The ratio (A1 to An) is determined. This mixing ratio corresponds to the wavelength spectrum of the arbitrary light. However, in the case of using Equation 10, a correction coefficient described later is required to correct the error in the photocurrent ratio.

数式２および数式１０が正しいことを確認した実験を報告する。実験ではアモルファスシリコンフォトダイオードを用いた。アモルファスシリコンフォトダイオードは豊橋技術科学大学の成膜装置により作製した素子である。ここでは、2つの波長に限定して実験を行う。   We report an experiment confirming that Equation 2 and Equation 10 are correct. In the experiment, an amorphous silicon photodiode was used. An amorphous silicon photodiode is an element produced by a film forming apparatus of Toyohashi University of Technology. Here, the experiment is limited to two wavelengths.

［実験］
［a-Si PDを用いた分光方法］
アモルファスシリコンフォトダイオード（a-Si PD）は波長依存特性を有しているため、任意の印加電圧値における入射光の光電流への変換率は波長毎に異なる。即ち、a-Si PDから得られる光電流特性から分光が可能であると考えられる。 [Experiment]
[Spectroscopic method using a-Si PD]
Since the amorphous silicon photodiode (a-Si PD) has wavelength-dependent characteristics, the conversion rate of incident light into photocurrent at an arbitrary applied voltage value varies depending on the wavelength. That is, it is considered that spectroscopy is possible from the photocurrent characteristics obtained from a-Si PD.

2波長（a[nm]とb[nm]）光から成る混合光における各波長光の光電流の割合をそれぞれXa，Xbとする。ここで、a-Si PDを用いた場合、混合光から得られる光電流の値は、2つの波長光を単波長で用いた場合に得られる光電流値の和と等しくならない（即ち、各波長光の光電流の割合の和は1にならない）。本分光方法では、数式１０において各波長光の光電流の割合の和が1に成ると定義して計算から分光結果を求める。故に、各波長光の光電流の混合割合の和が1になると定義された各波長光の光電流の割合をそれぞれAa，Abとすると、次式が成り立つ。
2 Wavelength (a [nm] and b [nm]), respectively the ratio of the photocurrent of each wavelength light in the mixed light comprising light X a, and X b. Here, when a-Si PD is used, the value of the photocurrent obtained from the mixed light is not equal to the sum of the photocurrent values obtained when two wavelengths of light are used at a single wavelength (ie, each wavelength). The sum of the photocurrents of light is not 1). In this spectroscopic method, it is defined that the sum of the photocurrent ratios of light of each wavelength is 1 in Formula 10, and the spectroscopic result is obtained by calculation. Therefore, when the ratio of the photocurrent of each wavelength light, which is defined as the sum of the mixing ratio of the photocurrent of each wavelength light, becomes 1, A a and A b respectively, the following equations are established.

数式１１においてF１，F2は各波長光の光電流の混合割合の和が1になると定義して計算を行った際に生じると考えられる誤差を補正するための係数である。即ち、F１，F2を用いて計算を行うことで、混合光における各波長光の光電流値を割合として表現することが可能となる。補正係数の値については［実験結果］にて述べる。以下ではAa ，Abの求め方について説明する。 In Formula 11, F 1 and F 2 are coefficients for correcting an error that is considered to occur when calculation is performed by defining that the sum of the mixing ratios of the photocurrents of the respective wavelength lights is 1. That is, by performing calculation using F 1 and F 2 , it is possible to express the photocurrent value of each wavelength light in the mixed light as a ratio. The value of the correction coefficient will be described in [Experimental results]. In the following, how to obtain A a and A b will be described.

Aa，Abを求める方法には、大きく分けて3つの工程（Step1〜3）がある。 The method for obtaining A a and A b is roughly divided into three steps (Steps 1 to 3).

Step1：図４に示すように、適当な印加電圧値V1（上記のV0に相当する。以下同様。）において（波長a[nm]とb[nm]の光から得られる）光電流Ia，Ibの値が一致するI-V特性をあらかじめ測定する。この時に、もう一つの任意の印加電圧値V2（上記のVnに相当する。以下同様。）における光電流Ia(V2)とIb(V2)の値を保管する。   Step 1: As shown in FIG. 4, photocurrents Ia and Ib (obtained from light of wavelengths a [nm] and b [nm]) at an appropriate applied voltage value V1 (corresponding to V0 described above, and so on). Measure IV characteristics with the same value in advance. At this time, the values of the photocurrents Ia (V2) and Ib (V2) at another arbitrary applied voltage value V2 (corresponding to Vn described above, the same applies hereinafter) are stored.

Step2：図５に示すように、混合光のI-V特性は、Ia，IbのI-V特性の間に収束することが分かっている。そこで、V1における混合光の光電流Imix(V1)の値から、Ia(V2)とIb(V2)の値を（保管してあるデータから）参照する。 Step 2: As shown in FIG. 5, it is known that the IV characteristics of the mixed light converge between the IV characteristics of I a and I b . Therefore, the values of Ia (V2) and Ib (V2) are referred to (from the stored data) from the value of the photocurrent Imix (V1) of the mixed light at V1.

Step3：ここで、数式１２を定義する。
Step 3: Here, Formula 12 is defined.

Imix(V2) ，Ia(V2) ，Ib(V2)の値を用いて、数式１２より次の方程式が成り立つ。
Using the values of Imix (V2), Ia (V2), and Ib (V2), the following equation is established from Equation 12.

また、先に述べたように、数式１０を用いる本分光方法では各波長光の光電流の割合の和が1に成ると定義して計算をする。よって次式が成り立つ。
Further, as described above, in the present spectroscopic method using Equation 10, the calculation is performed by defining that the sum of the ratios of the photocurrents of the respective wavelength lights is 1. Therefore, the following equation holds.

よって、数式１３と数式１４よりAaとAbを算出できる。 Therefore, A a and A b can be calculated from Equation 13 and Equation 14.

［a-Si PDを用いた2波長光の分光実験］
2波長光の分光実験を行った。実験は主に以下の2項目を行った。
・I-V特性の測定（Imix(V2) ，Ia(V2) ，Ib(V2)の測定）
・（Imix(V2) ，Ia(V2) ，Ib(V2)の測定結果より）混合割合Aa ，Abの算出
以下に実験の方法について述べる。 [Spectroscopic experiment of two-wavelength light using a-Si PD]
A two-wavelength light spectroscopic experiment was conducted. The experiment mainly performed the following two items.
・ Measurement of IV characteristics (measurement of Imix (V2), Ia (V2), Ib (V2))
· (Imix (V2), Ia (V2), from the measurement results of Ib (V2)) the mixing ratio A a, describes a method of experiments in the following calculation of the A b.

本実験では、自作の（PIN構造）水素化アモルファスシリコンPD（以降a-Si:H PD）を用いて実験を行っているため、まず、実験に使用したa-Si:H PDの構造及び構成作用について述べる。a-Si:H PDの構造は、基板用電極、正孔注入阻止層、光吸収層、電子注入阻止層、及び透明電極をこの順序に積層した構造となる。次に各層の構成作用を順次に述べる。   In this experiment, since the experiment was performed using a self-made (PIN structure) hydrogenated amorphous silicon PD (hereinafter a-Si: H PD), the structure and configuration of the a-Si: H PD used in the experiment was first used. The action will be described. The structure of a-Si: HPD is a structure in which a substrate electrode, a hole injection blocking layer, a light absorption layer, an electron injection blocking layer, and a transparent electrode are stacked in this order. Next, the configuration and operation of each layer will be described sequentially.

基板用電極は、その上の正孔注入阻止層と電気的に良好な接触をする金属電極である。正孔注入阻止層は、基板用電極からの光吸収層への正孔の注入を阻止し、暗電流の低減を図っている。具体的には、n型の単結晶シリコン層を使用し、さらに不純物濃度を1016〜1017[cm-3]として光吸収層への基板用電極側からの正孔の注入を抑え、低暗電流で波長依存特性のある構造となっている。光吸収層は、効率良く光を電荷に変換させるために、薄膜内の欠陥密度が低く、抵抗が高いほとんど不純物がドープされていない水素化アモルファスシリコン（a-Si : H）層で構成されている。電子注入阻止層は、透明電極からの光吸収層への電子の注入を阻止し、暗電流の低減を図っている。具体的には、p型の水素化アモルファス材料層（a-SiC : H）を用いている。透明電極は、光を透過させる必要があるため、酸化インジウム・錫や半透明金属電極を用いる。また、暗電流を低減させるために、電子注入阻止層に対して、ショットキ接触となる材料が使用されている。 The substrate electrode is a metal electrode that makes good electrical contact with the hole injection blocking layer thereon. The hole injection blocking layer blocks injection of holes from the substrate electrode into the light absorption layer, thereby reducing dark current. Specifically, an n-type single crystal silicon layer is used, and an impurity concentration of 10 16 to 10 17 [cm −3 ] is used to suppress injection of holes from the substrate electrode side into the light absorption layer, thereby reducing It has a wavelength dependent characteristic with dark current. The light-absorbing layer is composed of a hydrogenated amorphous silicon (a-Si: H) layer that has a low defect density in the thin film and has a high resistance and is hardly doped with impurities in order to efficiently convert light into charges. Yes. The electron injection blocking layer blocks the injection of electrons from the transparent electrode into the light absorption layer, thereby reducing the dark current. Specifically, a p-type hydrogenated amorphous material layer (a-SiC: H) is used. Since the transparent electrode needs to transmit light, indium oxide / tin oxide or a translucent metal electrode is used. In order to reduce the dark current, a material that makes a Schottky contact with the electron injection blocking layer is used.

実験に使用した、自作a-Si:H PDの暗電流特性を図６に示す。また、波長依存特性（波長[nm]-光電流[A]特性）を図７に示す。図７に示すように、a-Si:H PDには、印加電圧値毎に波長依存特性が変化する（光電流への変換効率が変化する）性質がある。この性質は、a-Si:H PD特有の性質であり、結晶Si PDには無い性質である。この性質は、波長依存特性と同様に、本分光方法における重要な要素である。即ち、各波長光から得られる光電流値が印加電圧値毎にどの様に変化するのかがあらかじめ分かっていれば、計算に用いる印加電圧値を複数設ける（3波長光の分光であれば、数式１３に加え、もう一つの印加電圧値V3における光電流値から新たに式が成り立つ）ことで、複数波長光の分光に対応することが可能となる。   FIG. 6 shows the dark current characteristics of self-made a-Si: HPD used in the experiment. FIG. 7 shows wavelength dependency characteristics (wavelength [nm] -photocurrent [A] characteristics). As shown in FIG. 7, the a-Si: HPD has a property that the wavelength-dependent characteristic changes for each applied voltage value (the conversion efficiency to photocurrent changes). This property is a property peculiar to a-Si: H PD and is not a property of crystalline Si PD. This property is an important factor in the present spectroscopic method as well as the wavelength-dependent characteristic. That is, if it is known in advance how the photocurrent value obtained from each wavelength light changes for each applied voltage value, a plurality of applied voltage values used for calculation are provided (if the spectrum of three-wavelength light is 13), a new equation is established from the photocurrent value at the other applied voltage value V3), and thus it is possible to deal with the spectrum of light having a plurality of wavelengths.

ただし、この性質は印加電圧値毎に光電流への変換効率が変化することを表すため、光量一定下でも計算に扱う各印加電圧値の光電流値毎に混合割合の計算結果が異なってしまうことになる。故に、印加電圧値毎に補正係数Fの値を変えて計算することで、計算結果が変化しないようにする必要がある。
次に、光源及び測定冶具を含む測定系について述べる。 However, since this property indicates that the conversion efficiency to photocurrent changes for each applied voltage value, the calculation result of the mixing ratio differs for each photocurrent value of each applied voltage value handled in the calculation even when the light amount is constant. It will be. Therefore, it is necessary to prevent the calculation result from changing by changing the value of the correction coefficient F for each applied voltage value.
Next, a measurement system including a light source and a measurement jig will be described.

図８に測定系（等価回路）を、図９に測定冶具の概観を示す。   FIG. 8 shows a measurement system (equivalent circuit), and FIG. 9 shows an overview of the measurement jig.

本実験では、光源には473[nm]の単色光を照射するレイザーダイオード（以下LD）と532[nm]の単色光を照射するLDを用いた。これらのLDはそれぞれ出力が調節可能である。   In this experiment, a laser diode (hereinafter referred to as LD) that emits 473 [nm] monochromatic light and an LD that emits 532 [nm] monochromatic light were used as the light source. Each of these LDs has an adjustable output.

2つのLDから出力された光をフィルタ等の光学機器を用いて集光し、a-Si PDに照射する。
・I-V特性の測定（Imix(V2) ，Ia(V2) ，Ib(V2)の測定） The light output from the two LDs is collected using an optical device such as a filter and applied to the a-Si PD.
・ Measurement of IV characteristics (measurement of Imix (V2), Ia (V2), Ib (V2))

a-Si PDにLDの光を照射した状態で、逆方向電圧を印加し、光電流値を測定した。ただし、光電流値の測定中は、LDの光量を一定とした。印加電圧値及び光電流値はケースレイ社製の半導体パラメータアナライザ4200SCSを用いて測定した。
・（Imix(V2) ，Ia(V2) ，Ib(V2)の測定結果より）混合割合Aa ，Abの算出
I-V特性の測定より得られた値（Imix(V2) ，Ia(V2) ，Ib(V2）を用いて、数式１３と数式１４より混合割合Aa ，Abを算出した。 A reverse voltage was applied to the a-Si PD irradiated with LD light, and the photocurrent value was measured. However, during measurement of the photocurrent value, the light amount of the LD was kept constant. The applied voltage value and the photocurrent value were measured using a semiconductor parameter analyzer 4200SCS manufactured by Caseley.
・ Calculation of mixing ratios A a and A b (from measurement results of Imix (V2), Ia (V2) and Ib (V2))
Using the values (Imix (V2), Ia (V2), and Ib (V2)) obtained from the measurement of IV characteristics, the mixing ratios A a and Ab were calculated from Equations 13 and 14.

ここで、以降では473[nm]光から得られる光電流をI473，532[nm]光から得られる光電流をI532とする。同様に、混合光中の各波長光から得られる光電流の混合割合をそれぞれA473 ，A532とする。 Hereafter, the photocurrent obtained from 473 [nm] light is I 473 , and the photocurrent obtained from 532 [nm] light is I 532 . Similarly, the mixing ratio of the photocurrent obtained from each wavelength light in the mixed light is A 473 and A 532 , respectively.

［実験条件］
表1に本実験の条件を示す。
[Experimental conditions]
Table 1 shows the conditions for this experiment.

ここで、V1，V2，Imix(V1)は、図４及び図５において示した印加電圧値及び光電流値に対応している。   Here, V1, V2, and Imix (V1) correspond to the applied voltage value and the photocurrent value shown in FIGS.

図４及び図５に基づいて本実験の条件を対応させた図（I-V特性）を図１０に示す。   FIG. 10 is a diagram (I-V characteristics) corresponding to the conditions of this experiment based on FIG. 4 and FIG.

本実験では、印加電圧値11[V]において、二種の光が入射したときの光電流I473とI532の値が一致するI-V特性をあらかじめ測定し、この二種の光が入射した時の印加電圧値6[V]における光電流I473(6V)とI532(6V)の値を予め（データベースとして）保管する。 In this experiment, at an applied voltage value of 11 [V], we measured in advance the IV characteristics where the values of photocurrents I 473 and I 532 when two types of light were incident, and when these two types of light were incident The values of the photocurrents I 473 (6V) and I 532 (6V) at an applied voltage value of 6 [V] are stored in advance (as a database).

また、印加電圧値11[V]においてI473とI532の値が一致したときにとりうる光電流値は上記二種の光の光量によって上記の例に限らずいくつか存在するが、本実験では6.0×10-9[A]であった場合について検討する。 In addition, there are several photocurrent values that can be taken when the values of I 473 and I 532 coincide with each other at an applied voltage value of 11 [V], depending on the light quantity of the two types of light. Consider the case of 6.0 × 10 -9 [A].

［実験結果］
次に、［a-Si PDを用いた分光方法］で説明した分光方法を用いて行った2波長光の分光実験の実験結果について述べる。また、最後に補正係数の算出についても述べる。
・I-V特性の測定（Imix(V2) ，I473(V2) ，I532(V2)の測定） [Experimental result]
Next, the experimental results of the two-wavelength light spectroscopic experiment performed using the spectroscopic method described in [Spectroscopic method using a-Si PD] will be described. Finally, the calculation of the correction coefficient is also described.
・ Measurement of IV characteristics (Imix (V2), I473 (V2), I532 (V2) measurement)

本実験項目では，具体的に2つのI-V特性を測定している。   In this experimental item, two IV characteristics are measured specifically.

1つ目は表1に示した条件の下に得られる、保管（データベース）用のI-V特性の測定である。このI-V特性の測定では、あらかじめ2つのLDをそれぞれ単体で用いて、印加電圧値11[V]において光電流値が6.0×10-9[A]となるようにLDの出力を調節の上、印加電圧値6[V]における光電流I473(6V) ，I532(6V) の値を測定するという方法により行った。 The first is the measurement of IV characteristics for storage (database) obtained under the conditions shown in Table 1. In the measurement of this IV characteristic, using two LDs alone in advance, after adjusting the output of the LD so that the photocurrent value becomes 6.0 × 10 -9 [A] at an applied voltage value of 11 [V], The measurement was performed by measuring the values of photocurrents I 473 (6V) and I 532 (6V) at an applied voltage value of 6 [V].

この測定より得られた各波長光のI-V特性を図１１に示す。図１１に示すI-V特性より、I473(6V)=3.06×10-9[A]，I532(6V)=4.94×10-9[A]という結果を得た。また、これらの値を（データベースとして）保管した。 The IV characteristics of each wavelength light obtained from this measurement are shown in FIG. From the IV characteristics shown in FIG. 11, the following results were obtained: I 473 (6V) = 3.06 × 10 −9 [A], I 532 (6V) = 4.94 × 10 −9 [A]. These values were also stored (as a database).

2つ目は、Imix(11V)=6.0×10-9[A]となる混合光のI-V特性の測定である。2つのLDから得られる混合光は、印加電圧値11[V]において光電流値が6.0×10-9[A]となるように出力を調節して用いた。なお、この例では混合光の光量を印加電圧値１１Vにおいて上記光電流値となるように調節しているが、これはあくまでも本方式が実現可能であることを示すためのものにすぎない。一般的には、任意の混合光に対応できるように、例えば、予め二種の光の光量と印加電圧を共に変化させたときの光電流値のデータベースを作成しておく。そして、当該データベースのうち、その場で測定された混合光の印加電圧値と光電流値の依存性に応じて、上記二種の光の光電流値が一致する印加電圧のうち、さらに混合光の光電流値とも一致する印加電圧を選択して上記の電圧V1とし、このときの光量を有する上記二種の光に対応する上記電圧V2（V2<V1）のときの光電流値を上記データベース中から参照する。また、以下のように混合光の上記電圧V2のときの光電流値はその場で測定する。 The second is measurement of the IV characteristics of mixed light with Imix (11V) = 6.0 × 10 −9 [A]. The mixed light obtained from the two LDs was used by adjusting the output so that the photocurrent value was 6.0 × 10 −9 [A] at an applied voltage value of 11 [V]. In this example, the light quantity of the mixed light is adjusted so as to be the above-described photocurrent value at the applied voltage value of 11 V, but this is only to show that this method can be realized. In general, for example, a database of photocurrent values when both the light quantity of two kinds of light and the applied voltage are changed is prepared in advance so as to cope with arbitrary mixed light. Then, in the database, depending on the dependency between the applied voltage value of the mixed light and the photocurrent value measured in situ, the mixed light is further selected from the applied voltages at which the photocurrent values of the two types of light match. The applied voltage that matches the photocurrent value of the above is selected as the above voltage V1, and the photocurrent value at the time of the voltage V2 (V2 <V1) corresponding to the two types of light having the light quantity at this time is stored in the database. Browse from inside. Further, the photocurrent value of the mixed light at the voltage V2 is measured on the spot as follows.

この測定より得られた混合光のI-V特性を図１２に示す。図１２に示すI-V特性より、印加電圧値6[V]における光電流Imix(6V)の値が、3.19×10-9[A]となることが分かった。 FIG. 12 shows the IV characteristics of the mixed light obtained from this measurement. From the IV characteristics shown in FIG. 12, it was found that the value of the photocurrent Imix (6V) at the applied voltage value 6 [V] was 3.19 × 10 −9 [A].

上記の2つのI-V特性の測定より、混合割合A473 ，A532の算出に必要となる光電流I473(6V) ，I532(6V) ，Imix(6V)の値として、I473(6V)=3.06×10-9[A]，I532(6V)=4.94×10-9[A]， Imix(6V)=3.19×10-9[A]が得られた。
・（Imix(V2) ，I473(V2) ，I532(V2)の測定結果より）混合割合A473 ，A532の算出 From the measurement of the above two IV characteristics, the values of the photocurrents I 473 (6V), I 532 (6V), and Imix (6V) required to calculate the mixing ratios A 473 and A 532 are I 473 (6V). = 3.06 × 10 -9 [A], I 532 (6V) = 4.94 × 10 -9 [A], Imix (6V) = 3.19 × 10 -9 [A].
・ Calculation of mixing ratios A 473 and A 532 (from Imix (V2), I 473 (V2), and I 532 (V2) measurement results)

次に、測定より得られたI473(6V) ，I532(6V) ，IMIX(6V)の値を式（3）に代入し、混合割合A473 ，A532を算出した。 Next, the values of I 473 (6V), I 532 (6V), and I MIX (6V) obtained from the measurement were substituted into Equation (3), and the mixing ratios A 473 and A 532 were calculated.

数式１３、数式１４より、次式が成り立つ。
From Expressions 13 and 14, the following expression is established.

この数式１５より逆行列を求めると数式１６が得られる。
When an inverse matrix is obtained from Equation 15, Equation 16 is obtained.

ここで、数式１６に実測値I473(V2)=I473(6V)=3.06×10-9[A]，I532(V2)=I532(6V)=4.94×10-9[A]，Imix(6V) =Imix(11V)=3.19×10-9[A]を代入すると数式１７が得られる。
Here, the measured value I 473 (V2) = I 473 (6V) = 3.06 × 10 −9 [A], I 532 (V2) = I 532 (6V) = 4.94 × 10 −9 [A], When Imix (6V) = Imix (11V) = 3.19 × 10 −9 [A] is substituted, Equation 17 is obtained.

数式１７を計算した結果、次の解が得られた。
As a result of calculating Expression 17, the following solution was obtained.

次に、補正係数の値について検討する。数式１１の説明で述べたように、a-Si:H PDの性質上、混合光から得られる光電流値は、（混合光の生成に用いた）2つの波長光を単波長で用いた場合に得られる光電流値の和と等しくならない（即ち、各波長光の光電流の割合の和は1にならない）。故に、数式１４に示す定義の下に計算を行っている。しかし、数式１４を用いて計算した場合、a-Si:H PDの性質を無視した計算結果が得られるため、理論値（実際の光電流の割合）に対し誤差が計算結果に生じると考えられる。そこで、補正係数を用いて誤差を補正（混合割合の和が1になるという計算を実現）する。この補正係数は各波長の光電流の和が１になるのであれば１である。しかし、光量と共に光電変換効率が変化するデバイスを用いる場合（各波長光の光電流の割合の和は1にならない場合）は、あらかじめFnを求めておく必要がある。求め方は２つある。１つ目は、各光量、各光電流の比率に対するFnの値を光電変換効率より計算する方法である。2つ目は、各光量、各光電流の比率に対するFnの値を実験より求める方法である。   Next, the value of the correction coefficient will be examined. As described in Equation 11, due to the nature of a-Si: HPD, the photocurrent value obtained from mixed light is the case where two wavelengths of light (used to generate mixed light) are used at a single wavelength. Is not equal to the sum of the photocurrent values obtained (ie, the sum of the photocurrent ratios of the light of each wavelength is not 1). Therefore, the calculation is performed under the definition shown in Formula 14. However, when the calculation is performed using Expression 14, a calculation result ignoring the properties of a-Si: HPD is obtained, and therefore an error is considered to occur in the calculation result with respect to the theoretical value (actual photocurrent ratio). . Therefore, the error is corrected using a correction coefficient (a calculation that the sum of the mixing ratios is 1 is realized). This correction coefficient is 1 if the sum of the photocurrents of the respective wavelengths is 1. However, when using a device whose photoelectric conversion efficiency varies with the amount of light (when the sum of the ratios of photocurrents of light of different wavelengths is not 1), it is necessary to obtain Fn in advance. There are two ways to find it. The first is a method of calculating the value of Fn with respect to the ratio of each light quantity and each photocurrent from the photoelectric conversion efficiency. The second method is to obtain the value of Fn with respect to the ratio of each light quantity and each photocurrent by experiment.

補正関数の値は、数式１８に示す解と、理論値（実際の光電流の割合）との関係から得る方法が最も信頼できる値を得る方法だと考えられる。ここで、理論値は、混合光の生成に用いた各LDの出力がそれぞれ分かっていることから、次式（数式１９）より得ることができる。
The value of the correction function is considered to be the method of obtaining the most reliable value from the relationship between the solution shown in Equation 18 and the theoretical value (actual photocurrent ratio). Here, the theoretical value can be obtained from the following equation (Equation 19) because the output of each LD used to generate the mixed light is known.

数式１９において、Imix'473(6V)，Imix'532(6V)は，それぞれImix(11V)=6.0×10-9[A]となる混合光を生成する際に用いた、各LDの出力と同じ出力の光を単波長で用いた場合の印加電圧値6[V]における光電流値である（注意：Imix'473(6V) ，Imix'532(6V)はI473(6V)，I532(6V) と同一の光電流ではない）。また、Imix' (6V)は，Imix'473(6V)とImix'532(6V) の和である。 In Equation 19, Imix ' 473 (6V) and Imix' 532 (6V) are the outputs of the LDs used when generating mixed light with Imix (11V) = 6.0 × 10 -9 [A], respectively. This is the photocurrent value at an applied voltage value of 6 [V] when light of the same output is used at a single wavelength (note: Imix ' 473 (6V), Imix' 532 (6V) are I 473 (6V), I 532 (It is not the same photocurrent as (6V)). Imix ' (6V) is the sum of Imix ' 473 (6V) and Imix' 532 (6V).

ここで、Imix'473(6V)=2.54×10-9[A]，Imix'532(6V)=1.21×10-9[A]であることが分かっているため，数式１９より、X473=0.677，X532=0.323が得られた。 Here, since it is known that Imix ' 473 (6V) = 2.54 × 10 -9 [A] and Imix' 532 (6V) = 1.21 × 10 -9 [A], from Equation 19, X 473 = 0.677, X 532 = 0.323 was obtained.

先に述べたように、補正係数の値は、実測値であるA473 ，A532の値と，理論値であるX473，X532の値との関係より算出する方法が適当だと考えられる。故に、次式より、A473 ，A532に対する補正係数F473，F532の値を算出した。
As described above, it is considered that the correction coefficient value is calculated from the relationship between the actual measurement values of A 473 and A 532 and the theoretical values of X 473 and X 532. . Therefore, the values of correction coefficients F 473 and F 532 for A 473 and A 532 were calculated from the following equations.

数式２０より、F473=0.73，F532=4.67が得られた。よって補正係数の値F473=0.73，F532=4.67を保管しておくことにより、数式１１を用いてX473，X532の値を本分光方法から得ることができる。ただし、ここで算出した補正係数の値は、基準電圧V2=6[V]における光電流値から算出した混合割合A473 ，A532に対する補正係数である。故に、基準電圧V2を他の電圧値にした場合には用いることができない。これは、先に述べたように、a-Si:H PDの波長依存特性が印加電圧値毎に異なる（波長及び光量一定の下でも印加電圧値毎に光電流への変換効率が異なる）ためである。したがって、補正係数を上記電圧V2ごとに予めデータベースとして保管しておく必要がある。また、上記電圧V1を上述のように選択可能とするためには、補正係数を上記電圧V1ごとに予めデータベースとして保管しておく必要がある。 From Equation 20, F 473 = 0.73 and F 532 = 4.67 were obtained. Therefore, by storing the correction coefficient values F 473 = 0.73 and F 532 = 4.67, the values of X 473 and X 532 can be obtained from this spectroscopic method using Equation 11. However, the value of the correction coefficient calculated here is a correction coefficient for the mixing ratios A 473 and A 532 calculated from the photocurrent value at the reference voltage V2 = 6 [V]. Therefore, it cannot be used when the reference voltage V2 is set to another voltage value. This is because the wavelength-dependent characteristics of a-Si: HPD differ for each applied voltage value as described above (the conversion efficiency to photocurrent varies for each applied voltage value even under a fixed wavelength and light amount). It is. Therefore, it is necessary to store the correction coefficient in advance as a database for each voltage V2. Further, in order to make the voltage V1 selectable as described above, it is necessary to store the correction coefficient as a database in advance for each voltage V1.

［実験結果の考察］
以上の実験結果をまとめると、以下のようになる。
[Consideration of experimental results]
The above experimental results are summarized as follows.

上記表2において、光量の混合割合とは、光量計を用いて測定した実際のLDからの各波長光の光量の混合割合（理論値）と、本実験より得られた光電流の混合割合を用いて算出した光量の混合割合（実測値）との比較である。   In Table 2 above, the mixing ratio of the light quantity is the mixing ratio (theoretical value) of the light quantity of each wavelength light from the actual LD measured using a light meter and the mixing ratio of the photocurrent obtained from this experiment. It is a comparison with the mixing ratio (actually measured value) of the light quantity calculated by using.

ここでは、分光の結果として光量の混合割合を得ることが最終的な目的ではないが、本分光方法を用いることで得られた実験結果の妥当性を確認するために光量の混合割合についても理論値と実測値を比較検討した。   Here, the final goal is to obtain the light intensity mixing ratio as a result of spectroscopy, but the light intensity mixing ratio is also theoretically used to confirm the validity of the experimental results obtained by using this spectroscopy method. The value and the measured value were compared.

光量の混合割合について実測値の算出方法を以下に示す。   The calculation method of the actual measurement value for the mixing ratio of the light quantity is shown below.

光量の割合は以下の3つの式より算出できる。   The ratio of the amount of light can be calculated from the following three formulas.

混合光の光量[W]をWMIX ，またa[nm]とb[nm]の波長光の光量をそれぞれWa ，Wbとすると、数式２１が成り立つ。
When the light amount [W] of the mixed light is W MIX , and the light amounts of the wavelength light of a [nm] and b [nm] are respectively W a and W b , Equation 21 is established.

ここで、a[nm]とb[nm]の波長光の光量の混合割合をそれぞれW'a ，W'bとすると、数式２２が成り立つ。
Here, if the mixing ratios of the light amounts of wavelengths a [nm] and b [nm] are W ′ a and W ′ b , Equation 22 is established.

ただし、Wa ，Wbは数式２３より算出される。ここで、ηは各波長光に対するPDの光電変換効率である。
However, W a and W b are calculated from Equation 23. Here, η is the photoelectric conversion efficiency of the PD for each wavelength light.

表2に示すように、光量の混合割合について実測値と理論値が非常に近似した値であることが分かる。故に、本分光方法にて2波長光の分光が実現可能であると考えられる。   As shown in Table 2, it can be seen that the actual measurement value and the theoretical value are very close to each other with respect to the mixing ratio of the light amount. Therefore, it is considered that two-wavelength light spectroscopy can be realized by this spectroscopy method.

以上述べた本実施形態における従来の技術（特開2008-241578）との大きな違いは以下の４点である。   The major differences from the conventional technique (Japanese Patent Laid-Open No. 2008-241578) in the present embodiment described above are the following four points.

１．材料：従来技術ではAPD（アバランシェフォトダイオード）に用いられる材料（Si結晶など）が対象であったが、本技術ではPD（フォトダイオード）に用いられる材料（Si結晶だけでなくアモルファスシリコン（a-Si））までが対象となる。そのため、a-Siの特徴である低温での成膜が可能となり、さまざまなデバイスへの積層化が実現できる。   1. Materials: The materials used in APDs (avalanche photodiodes) (Si crystals, etc.) were the subject of the conventional technology, but the materials used in PDs (photodiodes) were not only Si crystals but also amorphous silicon (a- Up to Si)). Therefore, it is possible to form a film at a low temperature, which is a feature of a-Si, and to realize lamination to various devices.

２．動作電圧：従来技術ではAPDを動作させるために高電圧（100V程度）を印加させる必要があったが、PD動作電圧（5V程度）の低電圧で動作可能となる。   2. Operating voltage: In the prior art, it was necessary to apply a high voltage (about 100V) to operate the APD, but it became possible to operate with a low PD operating voltage (about 5V).

３．光電流比率Anの合計が１となる式（数式１０）を利用する場合には、従来技術と違い、「比率の合計が1と定義する」ことにより、測定回数を減らすことが出来、測定による測定誤差を少なくすることが出来る。また同時に、測定回数を減らすことが出来、高速化が実現できる。   3. When using the formula (Formula 10) in which the sum of the photocurrent ratios An is 1, unlike the conventional technique, the number of measurements can be reduced by “defining the sum of ratios as 1”. Measurement error can be reduced. At the same time, the number of measurements can be reduced, and speeding up can be realized.

４．計算方法２（増倍率でなく電流値で計算）：従来技術では光電流値を測定し、その値を元に増倍率を求めなければ比率計算することができなかったが、本技術では電流値を測定すれば、その値を用いて、比率計算をすることができるため、計算にかかる時間が早くなる。また、増倍率を求めるために余分な回路機構も必要なくなる。   4). Calculation method 2 (calculated with current value instead of multiplication factor): In the prior art, the photocurrent value was measured, and the ratio could not be calculated without obtaining the multiplication factor based on that value. If the value is measured, the ratio can be calculated using the value, so that the time required for the calculation is shortened. Further, no extra circuit mechanism is required to obtain the multiplication factor.

以上本発明につき、好適な実施例を挙げて種々説明したが、本発明はこの実施例に限定されるものではなく、発明の精神を逸脱しない範囲内で多くの改変を施し得るのはもちろんである。   Although the present invention has been described in various manners with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. is there.

１ フォトダイオード（アモルファスシリコンフォトダイオード）
２ 基板用電極
３ 正孔注入素子層
４ 光吸収層
５ 電子注入阻止層
６ 透明電極 1 Photodiode (amorphous silicon photodiode)
2 Electrode for substrate 3 Hole injection element layer 4 Light absorption layer 5 Electron injection blocking layer 6 Transparent electrode

Claims (3)

任意の光の波長スペクトルを検出する方法であって、フォトダイオードに予め波長λnのｎ種の比較用の光を入射させたときの光電流値を検出しておき、フォトダイオードに前記任意の光を入射させたときの光電流値を検出し、以下の数式２４に基づいて、前記任意の光の各波長λnの光電流比率を検出することを特徴とするフォトダイオードを用いた波長スペクトル検出方法。
ここで、ｎは２以上の整数、Anは前記任意の光に含まれる各波長λnの光の光電流比率、Imix(Vn)はフォトダイオードに逆バイアス電圧Vnを印加し、前記任意の光を入射させた場合の光電流値、I[λn，Vn]は、逆バイアス電圧V0（V0はV1からVnより大きい電圧）を印加したときにImix(V0)と同じ光電流値になる光量を有する波長λnの前記比較用の光を入射させた場合において、逆バイアス電圧Vnを印加したときの光電流値である。
A method for detecting a wavelength spectrum of arbitrary light, wherein a photocurrent value when n types of comparative light of wavelength λn are incident on a photodiode in advance is detected, and the arbitrary light is detected on a photodiode. And detecting a photocurrent ratio at each wavelength λn of the arbitrary light based on the following Formula 24, and detecting a wavelength spectrum using a photodiode: .
Here, n is an integer of 2 or more, An is a photocurrent ratio of light of each wavelength λn included in the arbitrary light, Imix (Vn) is a reverse bias voltage Vn applied to the photodiode, and the arbitrary light is The incident photocurrent value, I [λn, Vn], has an amount of light that has the same photocurrent value as Imix (V0) when a reverse bias voltage V0 (V0 is a voltage greater than V1 to Vn) is applied. This is the photocurrent value when the reverse bias voltage Vn is applied when the comparative light of wavelength λn is incident.
任意の光の波長スペクトルを検出する方法であって、フォトダイオードに予め波長λnのｎ種の比較用の光を入射させたときの光電流値を検出しておき、フォトダイオードに前記任意の光を入射させたときの光電流値を検出し、以下の数式２５に基づいて、前記任意の光の各波長λn毎の光電流比率を検出することを特徴とするフォトダイオードを用いた波長スペクトル検出方法。
ここで、ｎは２以上の整数。Anは各波長光の光電流の混合割合の和が1になると仮定したときの前記任意の光に含まれる各波長λnの光の光電流比率、Imix(Vn-1)はフォトダイオードに逆バイアス電圧Vn-1を印加し、前記任意の光を入れた場合の光電流値、I[λn，Vn-1]は逆バイアス電圧V0（V0はV1からVnより大きい電圧）を印加したときにImix(V0)と同じ光電流値になる光量を有する波長λnの前記比較用の光を入射させた場合において、逆バイアス電圧Vn-1を印加したときの光電流値である。
A method for detecting a wavelength spectrum of arbitrary light, wherein a photocurrent value when n types of comparative light of wavelength λn are incident on a photodiode in advance is detected, and the arbitrary light is detected on a photodiode. A wavelength spectrum detection using a photodiode, wherein a photocurrent value at the time of incident light is detected and a photocurrent ratio for each wavelength λn of the arbitrary light is detected based on the following formula 25 Method.
Here, n is an integer of 2 or more. An is the photocurrent ratio of the light of each wavelength λn included in the arbitrary light, assuming that the sum of the mixing ratio of the photocurrent of each wavelength light is 1, and Imix (Vn-1) is the reverse bias to the photodiode When the voltage Vn-1 is applied and the above-mentioned arbitrary light is applied, the photocurrent value, I [λn, Vn-1] is Imix when the reverse bias voltage V0 (V0 is a voltage greater than V1 to Vn) is applied. This is the photocurrent value when the reverse bias voltage Vn-1 is applied in the case where the comparison light having the wavelength λn having the same light amount as that of (V0) is incident.
前記光電流比率Anから以下の数式２６に基づいて前記任意の光の波長λnの補正された光電流比率を求めることを特徴とする請求項２に記載のフォトダイオードを用いた波長スペクトル検出方法。
ここで、Xｎは波長λnの光により発生した補正後の光電流の比率（含有率）、Fnは各波長光の光電流の混合割合の和が１になると定義して計算を行った際に生じる誤差を補正する係数である。
3. The wavelength spectrum detection method using a photodiode according to claim 2, wherein a corrected photocurrent ratio of the wavelength λn of the arbitrary light is obtained from the photocurrent ratio An based on the following equation (26).
Here, Xn is the ratio (content ratio) of the corrected photocurrent generated by the light of wavelength λn, and Fn is calculated when the sum of the photocurrent mixing ratio of each wavelength light is defined as 1. This is a coefficient for correcting an error that occurs.
JP2009069347A 2009-03-23 2009-03-23 Wavelength spectrum detection method Expired - Fee Related JP5445906B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2009069347A JP5445906B2 (en) 2009-03-23 2009-03-23 Wavelength spectrum detection method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2009069347A JP5445906B2 (en) 2009-03-23 2009-03-23 Wavelength spectrum detection method

Publications (2)

Publication Number Publication Date
JP2010223646A true JP2010223646A (en) 2010-10-07
JP5445906B2 JP5445906B2 (en) 2014-03-19

Family

ID=43041003

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2009069347A Expired - Fee Related JP5445906B2 (en) 2009-03-23 2009-03-23 Wavelength spectrum detection method

Country Status (1)

Country Link
JP (1) JP5445906B2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101189909B1 (en) 2010-12-24 2012-10-10 크로마 에이티이 인코포레이티드 Method of inspecting mixed light state of simulation light emitting diode light source
JP2012207920A (en) * 2011-03-29 2012-10-25 Institute Of National Colleges Of Technology Japan Method for detecting wavelength spectrum
KR20160051471A (en) * 2014-11-03 2016-05-11 삼성전자주식회사 Spectrometer including vetical stack structure and non-invasive biometric sensor including the spectrometer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110501073A (en) * 2019-09-19 2019-11-26 成都维客昕微电子有限公司 Spectral method of detection and device based on single photodiodes

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5243591B2 (en) * 1972-06-14 1977-10-31
JPH08153888A (en) * 1994-09-30 1996-06-11 Kyocera Corp Photoelectric converter and optical sensor employing it
JP2008241578A (en) * 2007-03-28 2008-10-09 Institute Of National Colleges Of Technology Japan Wavelength spectrum detection method using avalanche photodiode

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5243591B2 (en) * 1972-06-14 1977-10-31
JPH08153888A (en) * 1994-09-30 1996-06-11 Kyocera Corp Photoelectric converter and optical sensor employing it
JP2008241578A (en) * 2007-03-28 2008-10-09 Institute Of National Colleges Of Technology Japan Wavelength spectrum detection method using avalanche photodiode

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
CSNC201008140512; 萩原大輔　他: '"ＡＰＤを用いた高精度な混合割合測定を目指した分光方法の提案"' 第５６回応用物理学関係連合講演会　講演予稿集 Ｖｏｌｕｍｅ　３, 20090330, Ｐａｇｅ　１１９０ *
JPN6013016254; ＹＡＮＧ，Ｄ．　他: '"Ｆｏｕｒ-ｃｏｌｏｒ　ｄｉｓｃｒｉｍｉｎａｔｉｎｇ　ｓｅｎｓｏｒ　ｕｓｉｎｇ　ａｍｏｒｐｈｏｕｓ　ｓｉｌｉｃｏｎ　ｄｒｉｆｔ-ｔｙｐｅ　ｐｈｏｔｏｄｉｏｄｅ"' Ｓｅｎｓｏｒｓ　ａｎｄ　Ａｃｔｕａｔｏｒｓ Ｖｏｌｕｍｅ　１４，　Ｉｓｓｕｅ　１, 198805, Ｐａｇｅｓ　６９-７７ *
JPN6013016256; 萩原大輔　他: '"ＡＰＤを用いた高精度な混合割合測定を目指した分光方法の提案"' 第５６回応用物理学関係連合講演会　講演予稿集 Ｖｏｌｕｍｅ　３, 20090330, Ｐａｇｅ　１１９０ *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101189909B1 (en) 2010-12-24 2012-10-10 크로마 에이티이 인코포레이티드 Method of inspecting mixed light state of simulation light emitting diode light source
JP2012207920A (en) * 2011-03-29 2012-10-25 Institute Of National Colleges Of Technology Japan Method for detecting wavelength spectrum
KR20160051471A (en) * 2014-11-03 2016-05-11 삼성전자주식회사 Spectrometer including vetical stack structure and non-invasive biometric sensor including the spectrometer
KR102323208B1 (en) * 2014-11-03 2021-11-08 삼성전자주식회사 Spectrometer including vetical stack structure and non-invasive biometric sensor including the spectrometer

Also Published As

Publication number Publication date
JP5445906B2 (en) 2014-03-19

Similar Documents

Publication Publication Date Title
Ullbrich et al. Emissive and charge-generating donor–acceptor interfaces for organic optoelectronics with low voltage losses
Stolterfoht et al. Visualization and suppression of interfacial recombination for high-efficiency large-area pin perovskite solar cells
Chen et al. Thorough subcells diagnosis in a multi-junction solar cell via absolute electroluminescence-efficiency measurements
Wang et al. High-performance position-sensitive detector based on graphene–silicon heterojunction
Hu et al. High gain Ga 2 O 3 solar-blind photodetectors realized via a carrier multiplication process
Fafard et al. Ultrahigh efficiencies in vertical epitaxial heterostructure architectures
Zheng et al. Vacuum ultraviolet photovoltaic arrays
Sogabe et al. Intermediate-band dynamics of quantum dots solar cell in concentrator photovoltaic modules
Chen et al. Zero-biased deep ultraviolet photodetectors based on graphene/cleaved (100) Ga 2 O 3 heterojunction
Proulx et al. Measurement of strong photon recycling in ultra‐thin GaAs n/p junctions monolithically integrated in high‐photovoltage vertical epitaxial heterostructure architectures with conversion efficiencies exceeding 60%
Cheriton et al. Two-photon photocurrent in InGaN/GaN nanowire intermediate band solar cells
Shu et al. Optical coupling from InGaAs subcell to InGaP subcell in InGaP/InGaAs/Ge multi-junction solar cells
JP5445906B2 (en) Wavelength spectrum detection method
Xie et al. High performance blue light detector based on ZnO nanowire arrays
Zeng et al. High-performance dual-mode ultra-thin broadband CdS/CIGS heterojunction photodetector on steel
Politi et al. Practical PV energy harvesting under real indoor lighting conditions
Tex et al. Charge separation in subcells of triple-junction solar cells revealed by time-resolved photoluminescence spectroscopy
Xie et al. Ultra-low dark current back-illuminated AlGaN-based solar-blind ultraviolet photodetectors with broad spectral response
Dai et al. High-response ultraviolet photodetector based on N, N’-bis (naphthalen-1-yl)-N, N’-bis (phenyl) benzidine and 2-(4-tertbutylphenyl)-5-(4-biphenylyl)-1, 3, 4-oxadiazole
Singh et al. Unveiling the potential of organometal halide perovskite materials in enhancing photodetector performance
Xu et al. UV-VIS-NIR broadband flexible photodetector based on layered lead-free organic-inorganic hybrid perovskite
Lin et al. Preparation and properties of Ni/InGaN/GaN Schottky barrier photovoltaic cells
Nesswetter et al. Determination of subcell IV parameters by a pulsed suns-Voc method including optical coupling
Paduthol et al. Addressing limitations of photoluminescence based external quantum efficiency measurements
Cai et al. Back-illuminated AlGaN heterostructure solar-blind avalanche photodiodes with one-dimensional photonic crystal filter

Legal Events

Date Code Title Description
A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A711

Effective date: 20120117

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A821

Effective date: 20120117

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20120321

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20130311

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20130409

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20130610

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20131008

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20131023

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20131112

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20131212

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

LAPS Cancellation because of no payment of annual fees