JP2005186175A - Carbon nanotube structure - Google Patents
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims description 8
- 239000002105 nanoparticle Substances 0.000 claims description 12
- 239000002041 carbon nanotube Substances 0.000 claims description 10
- 239000007772 electrode material Substances 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 229910001285 shape-memory alloy Inorganic materials 0.000 claims description 4
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 3
- 229910001000 nickel titanium Inorganic materials 0.000 claims 2
- 239000000463 material Substances 0.000 abstract description 19
- 239000000758 substrate Substances 0.000 abstract description 4
- PENWAFASUFITRC-UHFFFAOYSA-N 2-(4-chlorophenyl)imidazo[2,1-a]isoquinoline Chemical group C1=CC(Cl)=CC=C1C1=CN(C=CC=2C3=CC=CC=2)C3=N1 PENWAFASUFITRC-UHFFFAOYSA-N 0.000 abstract 1
- 229910010380 TiNi Inorganic materials 0.000 abstract 1
- 239000000523 sample Substances 0.000 description 10
- 238000000034 method Methods 0.000 description 8
- 230000005540 biological transmission Effects 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- 238000002844 melting Methods 0.000 description 7
- 238000010894 electron beam technology Methods 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 6
- 229910052721 tungsten Inorganic materials 0.000 description 6
- 239000010937 tungsten Substances 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 238000009429 electrical wiring Methods 0.000 description 5
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 230000005684 electric field Effects 0.000 description 4
- 239000013078 crystal Substances 0.000 description 3
- 238000011161 development Methods 0.000 description 3
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
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- 230000005533 two-dimensional electron gas Effects 0.000 description 2
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- 230000004075 alteration Effects 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000012620 biological material Substances 0.000 description 1
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- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
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- 230000005669 field effect Effects 0.000 description 1
- 239000003574 free electron Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
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Abstract
Description
本願発明は、カーボンナノチューブ（以下「ＣＮＴ」という。）の低抵抗電極に関するものである。 The present invention relates to a low resistance electrode of a carbon nanotube (hereinafter referred to as “CNT”).
電気配線の重要な要素は、電気伝導度であり、その電気伝導度は、ドゥルーデの式によるとσ＝ne2τ／m*（ｎは電子密度、ｍ＊は電子の有効質量、τは散乱によって電子の運動量が乱される平均時間）、又は、σ＝neμ（μ＝eτ／m*は移動度）で表現される。電気伝導度を向上させるためには、電子の散乱を減少させることが一つの方法であり、そのために使用する材料の結晶性を向上させ、τを大きくする技術、および電子や正孔の有効質量の小さい材料の選択及びそれを実現する新しい材料の開発が進められている。 An important element of electrical wiring is electrical conductivity. According to the Drude equation, σ = ne 2 τ / m * (n is the electron density, m * is the effective mass of the electron, and τ is the scattering. Is represented by σ = neμ (μ = eτ / m * is mobility). In order to improve electrical conductivity, one method is to reduce the scattering of electrons. For this purpose, a technique for improving the crystallinity of the material used, increasing τ, and the effective mass of electrons and holes. The selection of small materials and the development of new materials that achieve this are underway.
一つの例として、散乱をほとんど受けない伝導であるバリスティック伝導特性を有するＣＮＴを素子間の配線に用いたものが知られている（下記特許文献１参照）。その場合、ＣＮＴの電極としては、導電性の金属あるいはカーボンが用いられているが、配線自体は、バリスティック伝導特性を有していても、それと接続する電極が上記のものでは、全体として低抵抗になっていない。 As one example, there is known one using CNTs having ballistic conduction characteristics that are hardly subjected to scattering for wiring between elements (see Patent Document 1 below). In that case, conductive metal or carbon is used as the CNT electrode. However, even if the wiring itself has ballistic conduction characteristics, the electrode connected to it is low as a whole. There is no resistance.
また、携帯電話や衛星放送は、ギガヘルツ域の高周波が用いられているため、それらの心臓部分は、高速で動作するトランジスターが使われている。その代表的なものにＧａＡｓをベースにしたＨＥＭＴという素子がある。構造は、ＧａＡｓと（Ｇａ，Ａｌ）Ａｓのヘテロ界面からなる。その界面に形成された２次元自由電子気体を利用した電界効果トランジスタ（ＦＥＴ）がＨＥＭＴである。GaAs/(Ga,Al)As−HEMTが高速動作するのは、電子の移動度が高いことにある。GaAsの電子の有効質量は、m*=0.0067ｍ０（ｍ０は電子の質量）と極めて軽く高移動度の要因となっている。また試料の作成技術の進歩により低温で高移動度を達成できるようになった。ＨＥＭＴで利用しているヘテロ界面による２次元電子気体に代わりバリスティック伝導体を利用すると電子の高速移動が可能になり一層の高速素子の実現につながるものである。 In addition, since mobile phones and satellite broadcasting use high frequencies in the gigahertz range, transistors that operate at high speed are used at the heart of these cellular phones and satellite broadcasts. A typical example is an element called HEMT based on GaAs. The structure consists of a heterointerface of GaAs and (Ga, Al) As. A field effect transistor (FET) using a two-dimensional free electron gas formed at the interface is a HEMT. GaAs / (Ga, Al) As-HEMT operates at high speed because of its high electron mobility. Effective mass of GaAs of electrons, m * = 0.0067m 0 (m 0 is the electron mass) is a factor of very lightly high mobility. In addition, high mobility can be achieved at low temperatures due to advances in sample preparation technology. If a ballistic conductor is used instead of the two-dimensional electron gas at the hetero interface used in HEMT, electrons can move at high speed, leading to the realization of a further high-speed device.
また、走査型電子顕微鏡や透過型電子顕微鏡は、電子を試料に当てて物質の構造を観察する顕微鏡である。また電子線回折装置は、試料に電子線を当ててその回折パターンを解析し結晶構造について情報を得る装置である。従ってこれらの顕微鏡及び回折装置には、電子銃（電子放出源）が内蔵されている。 A scanning electron microscope or a transmission electron microscope is a microscope that observes the structure of a substance by applying electrons to a sample. The electron beam diffractometer is an apparatus that obtains information on the crystal structure by applying an electron beam to a sample and analyzing the diffraction pattern. Therefore, an electron gun (electron emission source) is built in these microscopes and diffraction devices.
電子銃には、熱電子放出型と電界放出型の二つのタイプがある。熱電子放出型としては、ＬａＢ６を陰極とするが、該陰極は、ＬaB6単結晶より針状に切り出し、その先端の曲率半径が１０μmになるまで研磨する。これを通電加熱し熱電子を発生させ陽極に向かう電子線として利用する。電子放出中の真空度は、１０−５Ｐａより真空でなければならない。その際、材料に求められる条件は、材料の融点が高い、高温で化学的に安定である、微細加工しやすい、物質の仕事関数が小さい等の条件である。LaB6は、仕事関数が小さいことで注目され走査型電子顕微鏡には、１９７０年代から利用され透過型電子顕微鏡には、１９８０年代から装着されるようになった。 There are two types of electron guns: thermionic emission type and field emission type. As a thermionic emission type, LaB 6 is used as a cathode, and the cathode is cut out in a needle shape from a LaB 6 single crystal and polished until the radius of curvature of its tip becomes 10 μm. This is energized and heated to generate thermoelectrons and use them as an electron beam toward the anode. The degree of vacuum during electron emission must be vacuum from 10 −5 Pa. At that time, conditions required for the material are conditions such as a high melting point of the material, chemical stability at a high temperature, easy microfabrication, and a small work function of the substance. LaB 6 has been attracting attention because of its small work function, and has been used in scanning electron microscopes since the 1970s, and has been attached to transmission electron microscopes since the 1980s.
電界放出型は、純粋な電界放出と、熱電界放出型がある。非常に強い電界下では、電子は、物質表面におけるショットキー障壁を通過して真空中にしみだし（トンネル効果）、陰極と陽極間に印加された電圧により、電子線を発生させる。陰極材料の多くは、タングステン単結晶であり、通常、＜３１０＞方位が先端方向に向けられる。電界放出は、超高真空（１０−８Pa）下において安定して使用可能である。しかし、超高真空下においても電圧印加初期においては、電子流は、安定しない。 The field emission type includes a pure field emission type and a thermal field emission type. Under a very strong electric field, electrons pass through the Schottky barrier on the surface of the material and penetrate into the vacuum (tunnel effect), and an electron beam is generated by a voltage applied between the cathode and the anode. Many of the cathode materials are tungsten single crystals, and the <310> orientation is usually oriented in the tip direction. Field emission can be used stably under ultra-high vacuum (10 −8 Pa). However, even under an ultra-high vacuum, the electron current is not stable at the initial stage of voltage application.
熱電界放出型においては、電界下で陰極が加熱されると、電子は、ポテンシャルの障壁を越えやすくなる。したがって、温度が高ければ、たとえ電界が弱くても、又は、温度がそれほど高くなくても電界が強ければ電子放出を行うことができる。熱電界放出は、通常後者の場合を指す。純粋な電界放出の場合に比べると電子の運動エネルギーのばらつきは、大きいが、陰極表面の吸着ガスの脱離やイオン衝撃による表面のあれの復元が早急に起こるので、少々低い真空度（１０−６Pa）下においても放出電子量を多くとることができる。この場合には、タングステンは、＜３１０＞方位ばかりでなく＜１００＞方位も用いられる。針に２０００Kで数キロボルトの正電位をかけると電子移動が起こり、（３１０）面又は（１００）面が再構築(Build-up)し、この面は、長時間安定になる。タングステン（１００）表面にZrOで表面処理すると仕事関数が著しく減少するため、走査型電子顕微鏡に広く利用されている。 In the thermal field emission type, when the cathode is heated under an electric field, electrons tend to cross the potential barrier. Therefore, if the electric field is weak if the temperature is high, or if the electric field is strong even if the temperature is not so high, electron emission can be performed. Thermal field emission usually refers to the latter case. Compared to the case of pure field emission, the variation in kinetic energy of electrons is large, but the desorption of the adsorbed gas on the cathode surface and the restoration of that surface due to ion bombardment occur quickly, so the degree of vacuum (10 − Even under 6 Pa), a large amount of emitted electrons can be obtained. In this case, tungsten uses not only the <310> orientation but also the <100> orientation. When a positive potential of several kilovolts is applied to the needle at 2000 K, electron transfer occurs and the (310) or (100) plane is built-up, and this plane becomes stable for a long time. Since the work function is remarkably reduced when the surface of tungsten (100) is treated with ZrO, it is widely used in scanning electron microscopes.
これに対して、ＣＮＴを探針として用いた走査型トンネル顕微鏡が知られている（下記特許文献２参照）。しかし、ここにおいてもＣＮＴの電極材料としては、磁性材料であるＦｅ，Ｃｏ，Ｎｉ，Ｃｒ，Ｍｎ，若しくはこれらの少なくとも一つを含む合金、又は化合物が用いられているが、磁性材料に限定される点、また、伝導特性の観点からも十分ではなかった。
電気配線の材料には、電線材料自身の発熱による電力損失の低減、結晶性の向上による散乱の抑制を目指して、アルミニウム又は銅配線が用いられている。しかしながら、室温で電子の散乱を十分に抑制できず拡散的伝導現象を利用した配線に留まっている。これを克服するには、試料の端から端まで散乱されずに電子が運動する必要がある。そのような伝導現象は、バリスティック伝導と呼ばれる。（それと対比する意味で電子が頻繁に散乱されながら試料中を運動する状況を拡散的伝導と呼ぶ。）これまでは、バリスティック伝導は、微細加工技術を駆使し、結晶性を良くし、さらに試料を低温にすることで初めて実現されていた。そのバリステリック伝導を室温以上で示す可能性のある材料がＣＮＴである。しかしながら、このＣＮＴの素晴らしい特性を生かす電極材料が未知であった。 As the material for the electrical wiring, aluminum or copper wiring is used for the purpose of reducing the power loss due to the heat generation of the wire material itself and suppressing the scattering by improving the crystallinity. However, the scattering of electrons cannot be sufficiently suppressed at room temperature, and the wiring remains using a diffusion conduction phenomenon. In order to overcome this, electrons need to move without being scattered from end to end of the sample. Such a conduction phenomenon is called ballistic conduction. (In contrast, the situation in which electrons move frequently in a sample while being scattered frequently is called diffusive conduction.) Until now, ballistic conduction has made use of microfabrication technology to improve crystallinity, This was realized for the first time by lowering the temperature of the sample. CNT is a material that can exhibit the varistic conduction at room temperature or higher. However, an electrode material that takes advantage of the excellent properties of this CNT has not been known.
また、高移動度を実現するには、これまでは、試料及び電子デバイス自身を低温にする必要があった。また、HEMT等の電子デバイスは、界面に２次元電子気体を実現し高速デバイスの実現を果たしたが、さらに低次元電子デバイスとして１次元電子気体を用いた電子デバイスや超高速なデバイスの開発がさまざまな情報通信機器の発展に伴い要求されている。その高速デバイス実現にバリスィック伝導を用いたデバイスがひとつの候補であり、その材料がＣＮＴである。しかしながら、ここでも、ＣＮＴの素晴らしい特性を生かす電極材料が未知であった。 In order to achieve high mobility, it has been necessary to lower the temperature of the sample and the electronic device itself. In addition, electronic devices such as HEMT have achieved high-speed devices by generating a two-dimensional electron gas at the interface. However, development of electronic devices using one-dimensional electron gas and ultra-high-speed devices as low-dimensional electronic devices has been achieved. It is required with the development of various information communication equipment. A device using ballistic conduction is one candidate for realizing the high-speed device, and the material is CNT. However, here too, the electrode material that takes advantage of the excellent properties of CNTs was unknown.
さらに、安定に動作する電子放出源には、針形状の作製、高温、高電圧、超高真空が要求される。これらの制約に束縛されることなく、さらに微小領域からの電子線発生、高輝度化、低真空動作することで、今まで走査型電子顕微鏡や透過型電子顕微鏡で不可能な試料（生体物質等を生きた状態で観察）を観察する、単純なレンズシステムによる顕微鏡構成および電子顕微鏡の超小型化の可能性が広がる。これを実現する電子源材料のひとつにＣＮＴがあるが、その特性を生かすＣＮＴに接合する材料が未知であった。 Furthermore, a stable electron emission source is required to have a needle shape, high temperature, high voltage, and ultra-high vacuum. Without being constrained by these restrictions, the generation of electron beams from minute areas, high brightness, and low vacuum operation have made it impossible to use a sample (biological material, etc.) that has been impossible with a scanning electron microscope or transmission electron microscope. The microscope configuration with a simple lens system and the possibility of ultra miniaturization of the electron microscope are widened. There is CNT as one of electron source materials for realizing this, but the material to be bonded to CNT that makes use of the characteristics has not been known.
以上のように、電気配線、電子デバイス、電子放出源においてＣＮＴを利用するためには、電極や基板とＣＮＴとの接合を改善し、理想的低抵抗状態であるバリスティック伝導になるようにしなければならないが、今までのところ、どのような接合材料にすれば、バリスティック伝導になるのかわかっていない状態である。 As described above, in order to use CNTs in electrical wiring, electronic devices, and electron emission sources, it is necessary to improve the bonding between electrodes and substrates and CNTs so as to achieve ideal low resistance state ballistic conduction. However, until now, it has not been understood what kind of bonding material is used for ballistic conduction.
本願発明においては、電極や基板とＣＮＴとの接合にＴｉＮｉを用いる。これにより、理想的低抵抗状態であるバリスティック伝導が達成されることを確認した。電極作製の場合においては、ＴｉＮｉナノ粒子を接合部分に塗布し、そこにＣＮＴを操作し配置する。その後、電極部分を加熱しＴｉＮｉを融解させ、ＣＮＴと既存の電極をＴｉＮｉで電気的機械的に良好な状態で固定する。その良否判断は、ＣＮＴの両端にある電極（ＴｉＮｉ）に電圧を印加しそのコンダクタンスが2e2/hの整数倍になっているかで判断する。 In the present invention, TiNi is used for bonding the electrode or substrate to the CNT. This confirmed that ballistic conduction, which is an ideal low resistance state, was achieved. In the case of electrode preparation, TiNi nanoparticles are applied to the joining portion, and CNTs are manipulated and arranged there. Thereafter, the electrode portion is heated to melt TiNi, and the CNT and the existing electrode are fixed with TiNi in an electromechanically good state. The quality is judged by applying a voltage to the electrodes (TiNi) at both ends of the CNT and determining whether the conductance is an integral multiple of 2e 2 / h.
ナノ粒子のＴｉＮｉを使用することで、バルクの融点よりも低い温度で粒子を融解することができる。それにより、デバイス作製時の他のプロセスとの整合性が増加し、熱過程による表面変質が防止できる。従ってナノ粒子を使用し融点温度を低下させることは、重要な要素の一つである。 By using nano-particle TiNi, the particles can be melted at a temperature lower than the bulk melting point. As a result, consistency with other processes during device fabrication increases, and surface alteration due to thermal processes can be prevented. Therefore, using nanoparticles and lowering the melting temperature is one of the important factors.
今までは、電極金属としては、ＴｉＮｉのみを挙げてきたが、ＴｉＮｉは、形状記憶合金として特に注目されている金属である。そこで、本件の電極としてもＴｉＮｉ以外の形状記憶合金である、ＡｕＣｄ合金あるいはＣｕＡｌＮｉ合金等も本願発明に係る合金であるＴｉＮｉに近い性質を示す可能性がある。 Up to now, only TiNi has been mentioned as the electrode metal, but TiNi is a metal that has attracted particular attention as a shape memory alloy. Therefore, there is a possibility that an AuCd alloy or a CuAlNi alloy, which is a shape memory alloy other than TiNi, also shows properties close to TiNi that is an alloy according to the present invention as the electrode of the present case.
また、本願発明においては、ナノ粒子を用いて融点の降下を行っており、通常の蒸着とは異なる接点形成を行っている。したがって、ＴｉＮｉにとどまらず、蒸着法では良好な電気的接合を行えない材料であっても、例えば、金のナノ粒子、アルミのナノ粒子、銅のナノ粒子等でも本願発明に係る合金であるＴｉＮｉに近い性質を示す可能性がある。 In the present invention, the melting point is lowered using nanoparticles, and contact formation different from normal vapor deposition is performed. Therefore, not only TiNi but also a material that cannot be satisfactorily electrically bonded by the vapor deposition method, for example, gold nanoparticles, aluminum nanoparticles, copper nanoparticles, etc., are TiNi that is an alloy according to the present invention. There is a possibility of exhibiting properties close to.
本願発明により、理想的なバリスティック伝導を実現することができ、電気配線においては、拡散的な伝導による電力損失を軽減でき、電子デバイスの低消費電力化につながる。また、ＣＮＴ自身のバリスティック伝導を利用した超高速デバイスを実現することが可能になり、大量な情報を低消費電力で転送することが可能になる。さらに、電子放出源としては、低真空、低電圧、及び微少領域からの電子放出が可能になり、電子顕微鏡及び電子線回折装置の構造の簡略化、高性能化（微少領域からの電子源を用いることで分解能が向上する）、超小型化が実現できる。 According to the present invention, ideal ballistic conduction can be realized. In electrical wiring, power loss due to diffusive conduction can be reduced, leading to lower power consumption of an electronic device. In addition, it becomes possible to realize an ultrahigh-speed device using the ballistic conduction of the CNT itself, and a large amount of information can be transferred with low power consumption. Furthermore, as an electron emission source, it becomes possible to emit electrons from a low vacuum, a low voltage, and a very small region, and the structure of the electron microscope and the electron beam diffractometer can be simplified and the performance can be improved. By using this, the resolution is improved), and miniaturization can be realized.
以下に、発明を実施するための最良の形態を示す。 The best mode for carrying out the invention will be described below.
ＣＮＴと既存の電極と接合させるのに適した接合材料を選択するには、ナノメートルスケールの直径を持つ一本のＣＮＴを接合材料の適切な位置に配置固定し、その後電気伝導度の測定を実施し、材料の適正比較をしなければならない。そこでナノメートルスケールで試料の操作を行うためには、ナノメートルスケールでの構造観察が可能な走査型電子顕微鏡や走査型透過型電子顕微鏡を使用し、ＣＮＴを操作しつつ架橋構造を作製し、その電気伝導計測を行った。 To select a bonding material suitable for bonding CNT to an existing electrode, a single CNT with a nanometer-scale diameter is placed and fixed at an appropriate position in the bonding material, and then electrical conductivity measurement is performed. Must be implemented and appropriate comparison of materials. Therefore, in order to operate the sample at the nanometer scale, a cross-linked structure is produced while operating the CNT using a scanning electron microscope or a scanning transmission electron microscope capable of observing the structure at the nanometer scale. The electrical conductivity was measured.
これまでの接続方法は、電線ビームを用いた真空中の残留炭素による固定、低融点金属による固定接続を行ってきた。しかし、その抵抗値は、数百キロオームを示し、理想的接続とはいえなかった。本願発明においては、接続できる金属材料の可能性を広げるために、接続部分の温度を１０００℃近くまで加熱できる走査型透過電子顕微鏡用ホルダーを作製し、ＣＮＴの両端を接続した。 Conventional connection methods have been fixed with residual carbon in a vacuum using a wire beam and fixed connection with a low melting point metal. However, the resistance value was several hundred kilohms, which was not an ideal connection. In the present invention, in order to expand the possibilities of metal materials that can be connected, a holder for a scanning transmission electron microscope capable of heating the temperature of the connection portion to near 1000 ° C. was prepared, and both ends of the CNT were connected.
図１を参照して、上記ホルダーについて説明する。電極兼ヒーターとしてタングステンを用いた。該ヒーターは、２本対向しており、１本のヒーターには、接続金属（TiNi）を塗布、もう一本のヒーターには、接続金属（TiNi）とＣＮＴをそれぞれ異なる位置に２箇所塗布する。 The holder will be described with reference to FIG. Tungsten was used as an electrode and heater. The two heaters are opposed to each other, and one heater is coated with a connecting metal (TiNi), and the other heater is coated with two connecting metals (TiNi) and CNT at different positions. .
このTiNiは、ナノ粒子（平均直径１００nm）を用いて、バルクよりは、融点の降下現象を考慮に入れて使用した。融点が高いとデバイス作製との整合性が悪化する。TiNiのナノ粒子を５００℃まで加熱し、その状態の中へＣＮＴの一端を操作して接触させ接合を作製する。すなわち、タングステン−TiNi−ＣＮＴの構造をまず作製する。 This TiNi was used with nanoparticles (average diameter 100 nm) taking into consideration the phenomenon of melting point lower than the bulk. If the melting point is high, the compatibility with device fabrication deteriorates. TiNi nanoparticles are heated to 500 ° C., and one end of the CNT is manipulated and brought into contact with the TiNi nanoparticles to form a bond. That is, a tungsten-TiNi-CNT structure is first prepared.
次にＣＮＴの自由端をもう一方のTiNiが塗布されたタングステン（５００℃に加熱）に接触させ、タングステン−TiNi−ＣＮＴ―TiNi−タングステンからなる架橋構造を作製した（図２参照）。両端の接続材料が同一でありデバイス化が可能である。 Next, the free end of CNT was brought into contact with the other tungsten coated with TiNi (heated to 500 ° C.) to produce a crosslinked structure of tungsten-TiNi-CNT-TiNi-tungsten (see FIG. 2). The connecting material at both ends is the same, and a device can be formed.
その後、架橋構造の両端に電圧を印加しその間に流れる電流を測定した（図３参照）。架橋直後は、高抵抗状態にあったが、ＣＮＴ間に２Vの電圧を印加すると高抵抗状態から低抵抗状態への遷移が観察された。その後に電圧を再印加すると低抵抗状態を維持して再現性よく動作した。この低抵抗状態の抵抗値を見積もったところ１３KΩであった。この値は、量子化コンダクタンス2e2／h=1／13kΩに対応する。この値が観測されたということは、ＣＮＴ自身が理想的なバリスティック伝導になっていることを示している。従って今回用いた接合法により、理論的に考えられる最良の電気的接触が作成されたといえる。従って、この接合法を配線、電子デバイス、電子放出源に適応すれば、理論的に最良の電気配線、電子デバイス、電子源になりうる。 Thereafter, a voltage was applied to both ends of the crosslinked structure, and the current flowing between them was measured (see FIG. 3). Immediately after cross-linking, it was in a high resistance state, but when a voltage of 2 V was applied between the CNTs, a transition from a high resistance state to a low resistance state was observed. When voltage was reapplied thereafter, the low resistance state was maintained and operation was performed with good reproducibility. The resistance value in this low resistance state was estimated to be 13 KΩ. This value corresponds to a quantized conductance 2e 2 / h = 1/13 kΩ. The observation of this value indicates that the CNT itself has ideal ballistic conduction. Therefore, it can be said that the best electrical contact that can be theoretically considered was created by the joining method used this time. Therefore, if this bonding method is applied to wirings, electronic devices, and electron emission sources, the theoretically best electrical wirings, electronic devices, and electron sources can be obtained.
電子の一次元伝導を利用した電子デバイス、バリスティック伝導を利用した高速電子デバイス、電力損失の少ない微小配線、微小領域からの電子放出源（走査型電子顕微鏡用電子源、透過型電子顕微鏡用電子源、ＣＮＴ電界放射型ディスプレイ）、低電圧印加での電子源、低真空で利用可能な電子源等に利用可能である。 Electron devices using one-dimensional conduction of electrons, high-speed electronic devices using ballistic conduction, minute wiring with low power loss, electron emission source from minute regions (electron source for scanning electron microscope, electron for transmission electron microscope) Source, a CNT field emission display), an electron source applied with a low voltage, an electron source usable in a low vacuum, and the like.
Claims (4)
The method for producing a carbon nanotube structure according to claim 3, wherein the nanoparticles are a nickel-titanium alloy.
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| JP2006051574A (en) * | 2004-08-12 | 2006-02-23 | National Institute Of Advanced Industrial & Technology | Installing method for nanometer-size material |
| WO2011142054A1 (en) * | 2010-05-10 | 2011-11-17 | 電気化学工業株式会社 | Electron source |
| CN114686923A (en) * | 2022-03-15 | 2022-07-01 | 大连交通大学 | Preparation method of intelligent molecular switch |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2006051574A (en) * | 2004-08-12 | 2006-02-23 | National Institute Of Advanced Industrial & Technology | Installing method for nanometer-size material |
| JP4517071B2 (en) * | 2004-08-12 | 2010-08-04 | 独立行政法人産業技術総合研究所 | How to install nano-sized materials |
| WO2011142054A1 (en) * | 2010-05-10 | 2011-11-17 | 電気化学工業株式会社 | Electron source |
| JP2011238459A (en) * | 2010-05-10 | 2011-11-24 | Denki Kagaku Kogyo Kk | Electron source |
| US8593048B2 (en) | 2010-05-10 | 2013-11-26 | Denki Kagaku Kogyo Kabushiki Kaisha | Electron source having a tungsten single crystal electrode |
| TWI489508B (en) * | 2010-05-10 | 2015-06-21 | Denki Kagaku Kogyo Kk | Electron source |
| CN114686923A (en) * | 2022-03-15 | 2022-07-01 | 大连交通大学 | Preparation method of intelligent molecular switch |
| CN114686923B (en) * | 2022-03-15 | 2023-11-10 | 大连交通大学 | Preparation method of intelligent molecular switch |
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