CN218215330U

CN218215330U - MoS 2/AlN-based deep ultraviolet photoelectric detector

Info

Publication number: CN218215330U
Application number: CN202222134042.7U
Authority: CN
Inventors: 唐鑫; 李国强; 郑昱林
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2022-08-15
Filing date: 2022-08-15
Publication date: 2023-01-03
Anticipated expiration: 2032-08-15

Abstract

The utility model discloses a MoS2 AlN base deep ultraviolet photoelectric detector, by supreme silicon substrate, silica layer, two dimension MoS2 material layer and the low AlN material layer of maintaining of including in proper order down, two dimension MoS2 material layer is equipped with first metal electrode, the low AlN material layer of maintaining is equipped with second metal electrode, two dimension MoS2 material layer and low AlN material layer of maintaining constitute high schottky barrier, form built-in electric field. The utility model discloses realize that two dimension MoS2 goes up low dimension AlN and grows, constructed the knot type heterojunction, demonstrate from power supply effect and very high deep ultraviolet responsivity, quick response ability.

Description

MoS 2/AlN-based deep ultraviolet photoelectric detector

Technical Field

The utility model relates to the field of semiconductor technology, concretely relates to MoS2 AlN base deep ultraviolet photoelectric detector.

Background

In recent years, low dimensional materials have proven to have great potential in the application of a new generation of optoelectronic devices. Due to the unique physical and chemical properties of low dimensional materials at the nanometer level, the low dimensional materials have become a popular target for research in the scientific research community and the industrial community. The AlN material has a direct band gap of 6.2eV, has good physical and chemical stability, high electron mobility and high thermal conductivity, and is one of the preferred materials for preparing the deep ultraviolet detector. At present, the AlN block material has proved to have good deep ultraviolet selectivity when applied to a photoelectric detector. When the AlN has the thickness of only a few nanometers, a structure similar to two-dimensional graphene can be formed, and as photogenerated carriers are limited in a low-dimensional space, the deep ultraviolet detection performance is more excellent.

At present, two-dimensional heterojunctions are a new research direction, and the photovoltaics effect among the heterojunctions materials is utilized, so that photocurrent can be generated under the condition of no external power supply. Molybdenum disulfide (MoS 2), the hottest two-dimensional material, with a direct band gap of 1.6eV, has demonstrated excellent performance in photodetection. If the MoS2 and AlN type detectors are successfully prepared, the method has a huge development prospect and is expected to be applied to the extreme fields of space communication, deep sea detection, geological detection and the like in the future. Nevertheless, alN material is easily grown in c-axis orientation, has a large lattice mismatch with the substrate, and easily forms a three-dimensional island structure, which is considered to be a worldwide problem.

SUMMERY OF THE UTILITY MODEL

In order to overcome not to have MoS2 and AlN type detector and AlN material and substrate to form the defect of three-dimensional island structure easily among the prior art, the utility model provides a MoS2/AlN base deep ultraviolet photoelectric detector.

The utility model discloses realized the growth of low dimension AlN material on two dimension MoS2, further provided one kind and had and improved low dimension AlN/MoS ₂ The deep ultraviolet photoelectric detector of the Schottky heterojunction can work without an external power supply, the problem that a complex filtering system needs to be additionally installed in a commercial deep ultraviolet detector is solved, meanwhile, the whole preparation process does not have complex operation, harmful byproducts are not generated, and an effective scheme is provided for a next-generation self-powered and high-performance deep ultraviolet photoelectric detector.

The utility model adopts the following technical scheme:

a low-dimensional AlN/MoS2 Schottky type deep ultraviolet photoelectric detector sequentially comprises a silicon substrate, a silicon dioxide layer, a two-dimensional MoS2 material layer and a low-dimensional AlN material layer from bottom to top, wherein the two-dimensional MoS2 material layer is provided with a first metal electrode, the low-dimensional AlN material layer is provided with a second metal electrode, and the two-dimensional MoS2 material layer and the low-dimensional AlN material layer form a high Schottky barrier to form a built-in electric field.

Further, the thickness of the silicon substrate is 300 to 400 μm, the crystal plane is (101), and the resistance is 0.01 to 0.1 Ω.

Further, the low-dimensional AlN material layer covers three quarters of the two-dimensional MoS2 material layer, and the coverage area is adjusted according to actual conditions according to actual processing requirements.

Further, the thickness of the silicon dioxide is 150-200 nm.

Further, the thickness of the low-dimensional AlN material layer is 5-15 nm.

Further, the thickness of the MoS2 material layer is 1-5 nm.

Further, the first metal electrode and the second metal electrode are respectively a Ti metal layer and an Au metal layer which are sequentially laminated from bottom to top; the thicknesses of the Ti metal layer and the Au metal layer are respectively 40-80 nm and 80-110 nm.

Further, the thickness of the Al layer is 3-12 nm.

The thickness of the Al layer directly determines the thickness of a subsequent AlN layer, if the Al layer is too thick, alN prepared subsequently is also very thick, and if the Al layer is too thin, alN material is discontinuous, so that the Al layer is not suitable for preparing devices.

Furthermore, the lengths of the first metal electrode and the second metal electrode are both 140-170 μm, and the widths of the first metal electrode and the second metal electrode are both 110-130 μm; the distance between the first metal electrode and the second metal electrode is 90-110 mu m.

A method for preparing the MoS 2/AlN-based deep ultraviolet photoelectric detector comprises the following steps:

after cleaning the silicon dioxide layer and the silicon substrate, preparing two-dimensional MoS2 material layers with different thicknesses by a chemical vapor deposition method to obtain MoS2/SiO2/Si;

transferring MoS2/SiO2/Si to electron beam evaporation to prepare Al layers with different thicknesses for evaporation so as to obtain Al/MoS2/SiO2/Si;

transferring the Al/MoS2/SiO2/Si into plasma chemical vapor deposition (PECVD), introducing nitrogen and ammonia, and turning on plasma radio frequency to realize the growth of low-dimensional AlN material layers with different thicknesses;

preparing Ti/Au electrodes with different thicknesses;

and placing the structure with the Ti/Au electrode in an annealing furnace for annealing treatment at different temperatures, so that ohmic contact is formed between the metal and the low-dimensional AlN material layer and the two-dimensional MoS2 material layer.

Further, two-dimensional MoS2 material layers with different thicknesses are prepared by a chemical vapor deposition method to obtain Al/MoS2/SiO2/Si, and the method specifically comprises the following steps:

taking 0.03-0.06 g of molybdenum oxide powder and 0.1-0.15 g of sulfur powder, wherein the growth distance is 15-20 cm, the air pressure is maintained at atmospheric pressure, the growth time is 10-15 minutes, and the growth temperature is 700-750 ℃.

Further, during the growth process of the AlN material layer: the ammonia gas/nitrogen gas is 50scmm/100sccm, the growth temperature is 800-900 ℃, the plasma intensity is 100-150W, the growth pressure is 10-100 kp, and the growth time is 20-30 minutes.

Preferably, the substrate is cleaned in step S1, including ultrasonic cleaning with water, acetone and ethanol for 5 to 10 minutes in sequence, and then dried with high-purity dry nitrogen.

Preferably, the growth process of MoS2 is specifically as follows, taking 0.03-0.06 g of molybdenum oxide powder and 0.1-0.15 g of sulfur powder, the growth distance is 15-20 cm, the air pressure is maintained at atmospheric pressure, the growth time is 10-15 minutes, and the growth temperature is 700-750 ℃;

in addition, the growth temperature and the plasma intensity of the plasma chemical vapor deposition directly determine the quality and the thickness of the AlN material layer; growth gas pressure affects the growth rate of the AlN material, and therefore, affects the thickness of the AlN material;

therefore, the ammonia gas/nitrogen gas is 50scmm/100sccm, the growth temperature is 800-900 ℃, the plasma intensity is 100-150W, the growth pressure is 10-100 kp, and the growth time is 20-30 minutes.

Further, the electrode preparation process is as follows: firstly, spin-coating positive photoresist for 50-60 s by a spin coater at the rotating speed of 4600-5000 rpm, carrying out prebaking (the temperature is 75-95 ℃ and the heating treatment is carried out for 4-5 min), exposing by a deep ultraviolet light source for 15-20 s, developing (the time is 60-65 s), carrying out reactive ion etching treatment by adopting plasma for 3-5 min, drying by hot nitrogen for 4-6 min, evaporating an electrode, and then carrying out ultrasonic oscillation in hot acetone for 8-10 min to remove the electrode in a photoresist area.

The annealing temperature is too high, which easily causes oxidation of MoS2 and affects device performance, and too low, which cannot realize good ohmic contact, and is preferably set to 550-600 ℃.

The utility model has the advantages that:

(1) The utility model discloses need not external power source and can work, the device demonstrates very high deep ultraviolet detection performance, mainly because the high schottky barrier between AlN and the MoS2 has formed powerful built-in electric field.

(2) A two-dimensional heterojunction structure of a low-dimensional material AlN and two-dimensional MoS2 is constructed, and the huge specific surface area, quantum confinement effect and high carrier mobility of the two-dimensional material are utilized. Meanwhile, no complex operation and other harmful byproducts are generated in the preparation process, and an effective scheme is provided for the next generation of self-powered and high-performance deep ultraviolet photoelectric detector.

(3) The utility model discloses the low knot type deep ultraviolet photoelectric detector of maintaining AlN material and two dimension MoS2 of preparation, the stable performance can be applied to extreme fields such as space communication, deep sea detection and geological survey, and economic benefits is considerable.

Drawings

FIG. 1 is a schematic sectional view of the structure of the present invention;

FIG. 2 is a diagram of a MoS2 thin film OM on SiO2/Si according to the present invention;

FIG. 3 is a schematic view of the present invention showing a layer of low-dimensional AlN material grown on a MoS2 thin film;

fig. 4 is an I-V performance diagram of an AlN/MoS2 schottky type deep ultraviolet photodetector under 280nm ultraviolet light according to an embodiment of the present invention;

fig. 5 is the I-T performance diagram of an AlN/MoS2 schottky deep ultraviolet photodetector under 280nm ultraviolet light.

Detailed Description

The present invention will be described in further detail with reference to the following examples and drawings, but the present invention is not limited thereto.

Examples

A MoS 2/AlN-based deep ultraviolet photodetector is shown in figures 1-3 and comprises a silicon substrate 1, a silicon dioxide layer 2, a two-dimensional MoS2 material layer 3 and a low-dimensional AlN material layer 4, wherein the two-dimensional MoS2 material layer is provided with a first metal electrode 5, the low-dimensional AlN material layer is provided with a second metal electrode 6, and the two-dimensional MoS2 material layer and the low-dimensional AlN material layer form a high Schottky barrier to form a built-in electric field.

The method comprises the following steps:

step 1, cleaning 200nm SiO2/(101) Si, and taking 0.03g of molybdenum oxide powder and 0.1g of sulfur powder by a Chemical Vapor Deposition (CVD) method, wherein the growth distance is 15cm, the air pressure is maintained at atmospheric pressure, the growth time is 10 minutes, the growth temperature is 700 ℃, and MoS2/SiO2/Si is obtained;

step 2, transferring the MoS2/SiO2/Si obtained in the step 1 to electron beam evaporation, and realizing 3nm Al layer evaporation by adopting a common process method to obtain Al/MoS2/SiO2/Si;

and 3, transferring the Al/MoS2/SiO2/Si obtained in the step 2 into plasma chemical vapor deposition (PECVD), introducing ammonia gas/nitrogen gas at 50scmm/100sccm, wherein the growth temperature is 800-900 ℃, the plasma intensity is 100W, the growth pressure is 10kpa, the growth time is 20 minutes, and the growth of low-dimensional AlN material layers with different thicknesses is realized.

And 4, spin-coating the positive photoresist for 50s by using a spin coater at the rotating speed of 4600rpm, carrying out prebaking (the temperature is 75 ℃ and the heating treatment is carried out for 4 min), exposing by using a deep ultraviolet light source for 15s, developing (the time is 60 s), carrying out reactive ion etching treatment by using plasma for 3min, drying by using hot nitrogen for 4min, evaporating an electrode, and then carrying out ultrasonic oscillation in hot acetone for 8 min to remove the electrode in the photoresist area.

And 5, putting the sample into an annealing furnace, setting the annealing temperature to be 550 ℃ and the annealing time to be 10 minutes, and obtaining the detector.

As shown in FIG. 4 and FIG. 5, the AlN/MoS2 Schottky type deep ultraviolet photoelectric detector prepared by the embodiment of the utility model shows a performance diagram under 280nm ultraviolet light, self-powered effect and very high deep ultraviolet responsivity and quick response capability.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be equivalent replacement modes, and all are included in the scope of the present invention.

Claims

1. The MoS 2/AlN-based deep ultraviolet photoelectric detector is characterized by sequentially comprising a silicon substrate, a silicon dioxide layer, a two-dimensional MoS2 material layer and a low-dimensional AlN material layer from bottom to top, wherein the two-dimensional MoS2 material layer is provided with a first metal electrode, the low-dimensional AlN material layer is provided with a second metal electrode, and the two-dimensional MoS2 material layer and the low-dimensional AlN material layer form a high Schottky barrier to form a built-in electric field.

2. The MoS 2/AlN-based deep ultraviolet photodetector of claim 1, wherein the layer of low-dimensional AlN material covers three-quarters of the two-dimensional MoS2 material layer.

3. The MoS 2/AlN-based deep ultraviolet photodetector of claim 1, wherein the silica has a thickness of 150 to 200nm.

4. The MoS 2/AlN-based deep ultraviolet photodetector of claim 1, wherein the low dimensional AlN material layer is 5-15 nm thick.

5. The MoS 2/AlN-based deep ultraviolet photodetector of claim 1, wherein the thickness of the two-dimensional MoS2 material layer is between 1 and 5nm.

6. The MoS 2/AlN-based deep ultraviolet photodetector of claim 1, wherein the first metal electrode and the second metal electrode are both a Ti metal layer and an Au metal layer which are sequentially laminated from bottom to top; the thicknesses of the Ti metal layer and the Au metal layer are respectively 40-80 nm and 80-110 nm.

7. The MoS 2/AlN-based deep ultraviolet photodetector of claim 1, wherein the first metal electrode and the second metal electrode both have a length of 140 to 170 μm and a width of 110 to 130 μm; the distance between the first metal electrode and the second metal electrode is 90-110 mu m.