阅读说明：本技术 一种悬空横向双异质结光探测器及其制作方法 (Suspended transverse double-heterojunction optical detector and manufacturing method thereof ) 是由 彭铭曾 郑新和 卫会云 于 2020-05-09 设计创作，主要内容包括：本发明提供一种悬空横向双异质结光探测器及其制作方法,该悬空横向双异质结光探测器包括：绝缘基底、支撑结构、第一电极、第二电极和由二维材料制成的二维结构；其中,支撑结构设置在绝缘基底上,第一电极和第二电极设置在支撑结构上；二维结构附着于支撑结构材料之上,按照二维结构与支撑结构的接触情况,分为第一接触区、第二接触区和悬空区；其中,在第一接触区和第二接触区处形成异质结。本发明利用悬空横向双异质结对光的吸收与光电转换特性进行光探测应用,制作方法简单易行,无需在二维材料表面上制作电极；一方面降低了高精度光刻的对准难度和制作成本；另一方面也避免了电极工艺对二维材料表面的污染和损伤,恶化器件的电学接触性能。(The invention provides a suspended transverse double-heterojunction optical detector and a manufacturing method thereof, wherein the suspended transverse double-heterojunction optical detector comprises: an insulating substrate, a support structure, a first electrode, a second electrode and a two-dimensional structure made of a two-dimensional material; wherein the support structure is disposed on the insulating substrate, and the first electrode and the second electrode are disposed on the support structure; the two-dimensional structure is attached to the supporting structure material and is divided into a first contact area, a second contact area and a suspended area according to the contact condition of the two-dimensional structure and the supporting structure; wherein a heterojunction is formed at the first contact region and the second contact region. The invention utilizes the absorption and photoelectric conversion characteristics of the suspended transverse double heterojunction to carry out optical detection application, the manufacturing method is simple and easy, and electrodes do not need to be manufactured on the surface of the two-dimensional material; on one hand, the alignment difficulty and the manufacturing cost of high-precision photoetching are reduced; on the other hand, the pollution and damage of the electrode process to the surface of the two-dimensional material are avoided, and the electrical contact performance of the device is deteriorated.)

1. A suspended lateral double-heterojunction photodetector, comprising: an insulating substrate, a support structure, a first electrode, a second electrode, and a two-dimensional structure made of a two-dimensional material; wherein the content of the first and second substances,

the support structure is disposed on the insulating substrate, and the first electrode and the second electrode are disposed on the support structure; the two-dimensional structure is attached to the supporting structure and is divided into a first contact area, a second contact area and a suspended area according to the contact condition between the two-dimensional structure and the supporting structure; wherein heterojunctions are formed at the first contact region and the second contact region, respectively.

2. The suspended lateral double heterojunction photodetector of claim 1, wherein the insulating substrate is made of any one of sapphire, silicon carbide, aluminum nitride, gallium nitride, indium phosphide, gallium arsenide, silicon oxide, silicon, or diamond.

3. The suspended lateral double-heterojunction photodetector of claim 1, wherein the material of the supporting structure is GaN-based, GaP-based, GaAs-based binary, ternary, quaternary or multi-element material, or ZnO-based, ZnS-based, ZnSe-based binary, ternary, quaternary or multi-element material, or any one of CdS-based, CdSe-based, CdTe-based binary, ternary, quaternary or multi-element material; the doping type of the supporting structure is n-type doping or p-type doping, and the supporting structure is a non-flat layer material with a micro-nano structure.

4. The suspended lateral double-heterojunction photodetector of claim 1, wherein the two-dimensional material is any one of transition metal chalcogenide, black phosphorus, graphene, group IV elemental two-dimensional material, group V elemental two-dimensional material, group III-V two-dimensional material, group III-VI two-dimensional material, or group IV-VI two-dimensional material.

5. The suspended lateral double-heterojunction photodetector of claim 1, wherein the heterojunction formed by said first contact region and said second contact region is an nn and pp homotype heterojunction or an np and pn inversion heterojunction.

6. The suspended lateral double-heterojunction photodetector of claim 1, wherein the first and second electrodes are metal electrodes formed by any one or a combination of more of titanium, aluminum, nickel, gold, silver, chromium, platinum and palladium, or ITO or graphene transparent conductive electrodes; and the first electrode and the second electrode are in electrical ohmic contact with the support structure.

7. A method of fabricating a suspended lateral double heterojunction photodetector as claimed in any of claims 1 to 6, wherein said method of fabricating comprises the steps of:

step one, preparing a single-layer complete film on an insulating substrate;

secondly, manufacturing a micro-nano structure graph on the upper surface of the single-layer complete film;

etching the single-layer complete film according to the micro-nano structure graph to obtain a supporting structure;

fourthly, manufacturing an electrode pattern on the supporting structure, and depositing a first electrode and a second electrode;

and fifthly, manufacturing a two-dimensional structure on the support structure with the electrode.

8. The method for fabricating the suspended lateral double-heterojunction photodetector of claim 7, wherein the single-layer complete thin film is grown or deposited by metal-organic chemical vapor deposition, molecular beam epitaxy, chemical vapor deposition, atomic layer deposition, magnetron sputtering.

9. The method for manufacturing the suspended transverse double-heterojunction photodetector as claimed in claim 7, wherein the micro-nano structure pattern and the electrode pattern are manufactured by adopting an optical lithography, an electron beam direct writing lithography or a nanoimprint patterning technology; the etching of the single-layer complete film is dry-method inductively coupled plasma etching, dry-method reactive ion etching or chemical wet etching.

10. The method of claim 7, wherein the two-dimensional structure is transferred from top to bottom to the support structure or epitaxially grown from bottom to top on the support structure.

Technical Field

The invention relates to the technical field of semiconductor heterostructure and optical detection, in particular to a suspended transverse double-heterojunction optical detector and a manufacturing method thereof.

Background

The photodetector is a detector manufactured by utilizing photoconduction, photovoltaic and photothermal effects caused by the absorption of light by semiconductors, and has wide application in various fields of military affairs and national economy. The optical detectors can be classified into ultraviolet, visible and infrared detectors according to different working bands. In the ultraviolet band, the high-voltage corona-free optical fiber is mainly applied to the military and civil dual-purpose fields of missile tracking, non-line-of-sight secret optical communication, marine fog-breaking navigation, high-voltage corona monitoring, fire early warning, biochemical detection, biomedicine and the like, and needs to work under extreme conditions of high temperature, space navigation, military and the like; the infrared radiation sensor is mainly used for ray measurement and detection, industrial automatic control, photometric measurement and the like in visible light or near infrared wave bands; the infrared band is mainly used for missile guidance, infrared thermal imaging, infrared remote sensing and the like.

The semiconductor photoelectric detector is an ideal photoelectric detector due to small volume, light weight, fast response speed and high sensitivity, is easy to integrate with other semiconductor devices, and can be widely applied to optical communication, signal processing, sensing systems and measuring systems. Semiconductor materials have undergone rapid development from first-generation Si-based materials, second-generation III-V group compound semiconductors (GaAs, InP, etc.) to third-generation wide bandgap semiconductor materials (represented by GaN, SiC), and accordingly, the spectral response range of semiconductor photodetectors has been gradually expanded and perfected from infrared, visible, ultraviolet, and deep ultraviolet bands.

In recent years, information functional materials have also been developed from three-dimensional (3D) bulk materials to thin, ultra-thin, and even two-dimensional (2D) monoatomic layer materials. Emerging two-dimensional materials provide new supports and supplements for optical detection applications. As a typical representative of two-dimensional materials, Graphene (Graphene) has extremely high light transmittance, and single-layer Graphene has an absorption efficiency of only 2.3%, and is easily saturated in light absorption, but absorbs light in a wide wavelength range, and can cover visible light and infrared light. Secondly, the two-dimensional transition metal chalcogenide (TMDCs) family is rich in materials and adjustable in forbidden bandwidth, wherein MoS₂As a kind ofUltra-thin two-dimensional semiconductor with high carrier mobility (410 cm)²V^-1s^-1) And an optical band gap (single layer 1.8eV) adjustable with the layer thickness, which is an ideal material for preparing visible light and even near infrared photoelectric detectors; PtSe₂From a single layer of PtSe due to its tunable band gap₂Bulk PtSe with (1.2eV) transition to zero bandgap₂The response wave band is from near infrared wave band to middle infrared wave band. In addition, the two-dimensional black phosphorus also has the characteristics of controllable band gap (0.3eV-2.0eV) and high carrier mobility (10 eV)³cm²V^-1s^-1) High current on-off ratio (10)⁴-10⁵) And anisotropy, etc., make it an important candidate material for photoelectric detectors. In general, photodetectors based on two-dimensional materials have exhibited the advantages of broadband response and high sensitivity, and their operating bands are mainly focused in the visible, near-infrared to far-infrared regions.

Due to the demand of ultra-high speed optical communication, signal processing, measurement and sensing systems, ultra-high speed and high sensitivity semiconductor photodetectors are required, and the next generation of photodetectors is developing towards room temperature, multi-band, high integration, high performance, low power consumption and low cost. The integration design and heterogeneous construction of emerging two-dimensional semiconductor materials and traditional advanced semiconductor materials provide new opportunities for the development and application of future optical detection technologies.

At present, the existing optical detector is to manufacture electrodes on the surface of a two-dimensional material, so that the manufacturing cost is high, the process is complex, and the electrode process can cause pollution and damage to the surface of the two-dimensional material, thereby deteriorating the electrical contact performance of the device.

Disclosure of Invention

The invention aims to solve the technical problem of providing a suspended transverse double-heterojunction photodetector and a manufacturing method thereof, and aims to solve the problem of performance complementation of the conventional discrete 3D and 2D material photodetectors on the one hand, and eliminate the influence of the substrate action by the suspended transverse structure in the invention on the other hand, so that the surface damage and pollution of a two-dimensional material are avoided, a high-performance self-supporting two-dimensional material can be obtained, the manufacturing method is simplified, and the manufacturing cost is reduced.

In order to solve the technical problems, the invention provides the following technical scheme:

a suspended lateral double heterojunction photodetector, comprising: an insulating substrate, a support structure, a first electrode, a second electrode, and a two-dimensional structure made of a two-dimensional material; wherein the content of the first and second substances,

the support structure is disposed on the insulating substrate, and the first electrode and the second electrode are disposed on the support structure; the two-dimensional structure is attached to the supporting structure and is divided into a first contact area, a second contact area and a suspended area according to the contact condition between the two-dimensional structure and the supporting structure; wherein heterojunctions are formed at the first contact region and the second contact region, respectively.

Further, the insulating substrate is made of any one of sapphire, silicon carbide, aluminum nitride, gallium nitride, indium phosphide, gallium arsenide, silicon oxide, silicon and diamond.

Furthermore, the material of the support structure is GaN-based, GaP-based, GaAs-based binary, ternary, quaternary or multi-component material, or ZnO-based, ZnS-based, ZnSe-based binary, ternary, quaternary or multi-component material, or any one of CdS-based, CdSe-based, CdTe-based binary, ternary, quaternary or multi-component material; the doping type of the supporting structure is n-type doping or p-type doping, and the supporting structure is a non-flat layer material with a micro-nano structure.

Further, the two-dimensional material is any one of transition metal chalcogenide, black phosphorus, graphene, group IV simple substance two-dimensional material, group V simple substance two-dimensional material, group III-V two-dimensional material, group III-VI two-dimensional material or group IV-VI two-dimensional material.

Further, the heterojunction formed by the first contact region and the second contact region is an nn and pp homotype heterojunction or an np and pn inversion heterojunction.

Further, the first electrode and the second electrode are metal electrodes formed by any one or combination of more of titanium, aluminum, nickel, gold, silver, chromium, platinum and palladium, or the first electrode and the second electrode are ITO or graphene transparent conductive electrodes; and the first electrode and the second electrode are in electrical ohmic contact with the support structure.

Accordingly, in order to solve the above technical problems, the present invention further provides the following technical solutions:

a method for manufacturing the suspended lateral double-heterojunction optical detector comprises the following steps:

step one, preparing a single-layer complete film on an insulating substrate;

secondly, manufacturing a micro-nano structure graph on the upper surface of the single-layer complete film;

etching the single-layer complete film according to the micro-nano structure graph to obtain a supporting structure;

fourthly, manufacturing an electrode pattern on the supporting structure, and depositing a first electrode and a second electrode;

and fifthly, manufacturing a two-dimensional structure on the support structure with the electrode.

Further, the single-layer complete film is grown or deposited by adopting a metal organic chemical vapor deposition, molecular beam epitaxy, chemical vapor deposition, atomic layer deposition and magnetron sputtering method.

Further, the micro-nano structure graph and the electrode graph are manufactured by adopting an optical photoetching, electron beam direct writing photoetching or nanoimprint patterning technology; the etching of the single-layer complete film is dry-method inductively coupled plasma etching, dry-method reactive ion etching or chemical wet etching.

Further, the two-dimensional structure is transferred to the support structure from top to bottom or epitaxially grown on the support structure from bottom to top.

The technical scheme of the invention has the following beneficial effects:

1. the suspended transverse double-heterojunction optical detector has a simple structure and strong adjustability, the spectral response wavelength of the optical detector is continuously covered from ultraviolet to infrared, and the optical detector has good semiconductor compatibility and system integration;

2. the suspended transverse double-heterojunction optical detector can eliminate the adverse effect of the substrate on the two-dimensional material, and can fully exert the photoelectric property of the two-dimensional material;

3. the suspended transverse double-heterojunction photodetector has very small background dark current and high sensitivity;

4. the method for manufacturing the suspended transverse double-heterojunction optical detector is simple and easy to implement, and does not need to manufacture electrodes on the surface of a two-dimensional material: on one hand, the alignment difficulty and the manufacturing cost of high-precision photoetching are reduced; on the other hand, the pollution and damage of the electrode process to the surface of the two-dimensional material are avoided, and the electrical contact performance of the device is deteriorated.

Drawings

Fig. 1 is a schematic diagram of a suspended lateral double-heterojunction photodetector according to a first embodiment of the present invention;

fig. 2 is a schematic flow chart of a method for fabricating a suspended lateral double-heterojunction photodetector according to a second embodiment of the present invention;

FIG. 3 is a schematic diagram of a suspended lateral MoS according to a third embodiment of the present invention₂Schematic diagram of/GaN inversion type double heterojunction light detector.

Description of reference numerals:

l1, insulating substrate; l2, support structure; l3, two-dimensional structure; p1, a first electrode;

r1, first contact zone; r2, a suspended area; r3, second contact zone; p2, second electrode.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

First embodiment

Referring to fig. 1, the present embodiment provides a suspended lateral double-heterojunction photodetector, which includes: an insulating substrate L1, a support structure L2, a first electrode P1, a second electrode P2, and a two-dimensional structure L3 made of a two-dimensional material; wherein a support structure L2 is disposed on an insulating substrate L1, and a first electrode P1 and a second electrode P2 are disposed on the support structure L2; the two-dimensional structure L3 is attached to the support structure L2, and is divided into a first contact region R1, a second contact region R3 and a suspended region R2 according to the contact condition between the two-dimensional structure L3 and the support structure L2; wherein heterojunctions are formed at the first contact region R1 and the second contact region R3, respectively.

The first contact region R1 and the second contact region R3 correspond to a heterojunction formed between the two-dimensional structure L3 and the support structure L2 therebelow, respectively, and the suspended region R2 corresponds to a suspended unsupported structure material below the two-dimensional structure L3, and is in a suspended state. The suspended lateral double-heterojunction photodetector of the embodiment is formed by a first electrode P1, a support structure L2, a first contact region R1, a suspended region R2, a second contact region R3, and support structure materials L2 to a second electrode P2, and the light absorption and photoelectric conversion characteristics of light are utilized by the suspended lateral double-heterojunction for photodetection application, so that the suspended lateral double-heterojunction photodetector is formed.

Among them, the material of the insulating substrate L1 in the present embodiment is preferably the following material: sapphire (Sapphire), silicon carbide (SiC), aluminum nitride (AlN), gallium nitride (GaN), indium phosphide (InP), gallium arsenide (GaAs), silicon oxide (SiO)₂) Silicon (Si), or diamond.

The material of the support structure L2 may be a GaN-based, GaP-based, GaAs-based binary, ternary, quaternary or multi-component material, or a ZnO-based, ZnS-based, ZnSe-based binary, ternary, quaternary or multi-component material, or a CdS-based, CdSe-based, CdTe-based binary, ternary, quaternary or multi-component material. The doping type of the support structure L2 may be n-type doping or p-type doping, and is a non-planar layer material with a micro-nano structure.

The two-dimensional material is preferably transition metal chalcogenide (TMDCs), Black Phosphorus (BP), Graphene (Graphene), group IV elementary substance two-dimensional material, group V elementary substance two-dimensional material, group III-V two-dimensional material, group III-VI two-dimensional material, group IV-VI two-dimensional material.

The heterojunction formed by the first contact region R1 and the second contact region R3 is preferably an nn and pp homotype heterojunction or an np and pn inversion heterojunction.

The first electrode P1 and the second electrode P2 can be metal electrodes formed by any one or combination of titanium, aluminum, nickel, gold, silver, chromium, platinum, palladium and other metals, or ITO, graphene transparent conductive electrodes; the first electrode P1 and the second electrode P2 are in electrical ohmic contact with the support structure L2.

In the embodiment, the light detection application is carried out by utilizing the absorption and photoelectric conversion characteristics of the suspended transverse double-heterojunction light to form the suspended transverse double-heterojunction light detector, the manufacturing method is simple and easy to implement, and electrodes do not need to be manufactured on the surface of a two-dimensional material; on one hand, the alignment difficulty and the manufacturing cost of high-precision photoetching are reduced; on the other hand, the pollution and damage of the electrode process to the surface of the two-dimensional material are avoided, and the electrical contact performance of the device is deteriorated.

Second embodiment

Referring to fig. 2, the present embodiment provides a method for fabricating the above-mentioned suspended lateral double-heterojunction photodetector, which includes the following steps:

s1, preparing a single-layer complete film on an insulating substrate L1;

referring to fig. 1, the above steps are specifically: and growing or depositing a single-layer complete film on the insulating substrate L1 by using a Metal Organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy (MBE), Chemical Vapor Deposition (CVD), Atomic Layer Deposition (ALD) or magnetron sputtering (Magnetronsputtering) method.

S2, manufacturing a micro-nano structure pattern on the upper surface of the single-layer complete film;

referring to fig. 1, the above steps may specifically be: and manufacturing a micro-nano structure graph on the upper surface of the single-layer complete film by utilizing an optical photoetching, electron beam direct writing photoetching or nanoimprint patterning technology.

S3, etching the single-layer complete film to obtain a supporting structure L2;

referring to fig. 1, the above steps are specifically: and etching the single-layer complete film by adopting dry Inductively Coupled Plasma (ICP), dry Reactive Ion Etching (RIE) or chemical wet method to obtain the supporting structure L2.

S4, making an electrode pattern on the support structure L2, and depositing a first electrode P1 and a second electrode P2;

referring to fig. 1, the above steps may specifically be: on the support structure L2, an electrode pattern is made using optical lithography, electron beam direct write lithography, or nanoimprint patterning techniques, and then the first electrode P1 and the second electrode P2 are evaporated or sputtered using an electron beam.

And S5, manufacturing a two-dimensional structure on the support structure with the electrodes.

Referring to fig. 1, the above steps may specifically be: the two-dimensional material is transferred to a support structure L2 with electrodes by a top-down method, or epitaxially grown on a support structure L2 by a bottom-up method to form a two-dimensional structure L3. Finally, the suspended lateral double heterojunction photodetector of the invention is formed.

The method for manufacturing the suspended transverse double-heterojunction optical detector is simple and feasible, and does not need to manufacture electrodes on the surface of a two-dimensional material; on one hand, the alignment difficulty and the manufacturing cost of high-precision photoetching are reduced; on the other hand, the pollution and damage of the electrode process to the surface of the two-dimensional material are avoided, and the electrical contact performance of the device is deteriorated.

Third embodiment

Referring to fig. 3, the present embodiment provides a suspended horizontal MoS₂The manufacturing method of the GaN inversion type double heterojunction photodetector comprises the following steps:

(a) epitaxially growing a 1-micron thick p-type GaN thin film (doped with Mg and p-type doping concentration of 1 x 10) on a c-plane sapphire substrate by MOCVD¹⁸/cm³)；

(b) Utilizing ultraviolet lithography to manufacture a micro-nano grid strip-shaped structure, wherein the length of each grid strip is 10 micrometers, the width of each grid strip is 2 micrometers, and the distance between every two adjacent grid strips is 2 micrometers;

(c) etching the p-type GaN film by a Cl-based ICP dry method to obtain a p-type GaN supporting structure material with a micro-nano grid bar structure;

(d) on a p-type GaN supporting structure material, an electrode pattern is manufactured by utilizing ultraviolet lithography, then 5nm nickel (Ni) and 50nm gold (Au) metal electrodes are deposited by adopting electron beam evaporation, and then good ohmic contact is formed by annealing for 5 minutes at 500 ℃ in an air atmosphere;

(e) adopts a top-down method to form a single-layer MoS₂The dry method was transferred to a p-type GaN support structure material with electrodes to produce the suspended lateral MoS of the present example₂A/GaN inversion type double heterojunction photodetector.

Fourth embodiment

The present embodiment provides a suspended horizontal PtSe₂The manufacturing method of the GaAs homotype double-heterojunction photodetector comprises the following steps:

(a) on the insulating GaAs substrate, an n-type GaAs film (doped with Te and having n-type doping concentration of 3 x 10) with a thickness of 2 μm was epitaxially grown by MBE¹⁸/cm³)；

(b) Utilizing ultraviolet lithography to manufacture a micro-nano grid strip-shaped structure, wherein the length of each grid strip is 10 micrometers, the width of each grid strip is 2 micrometers, and the distance between every two adjacent grid strips is 5 micrometers;

(c) etching the n-type GaAs film by a Cl-based ICP dry method to obtain an n-type GaAs supporting structure material with a micro-nano grid bar structure;

(d) on an n-type GaAs supporting structure material, an electrode pattern is manufactured by utilizing ultraviolet lithography, then a 40nm germanium (Ge) and 80nm gold (Au) metal electrode is deposited by adopting electron beam evaporation, and then annealing is carried out at 350 ℃ in a nitrogen atmosphere for 20 seconds to form good ohmic contact;

(e) by mechanical lift-off from top to bottom, few layers of PtSe are formed₂Dry transfer to n-type GaAs support structure material with electrodes to produce suspended transverse PtSe of the embodiment₂A GaAs homotype double-heterojunction light detector.

Further, it should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

Finally, it should be noted that while the above describes a preferred embodiment of the invention, it will be appreciated by those skilled in the art that, once they have learned the basic inventive concepts of the present invention, numerous modifications and adaptations may be made without departing from the principles of the invention, which are intended to be covered by the claims. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.