阅读说明：本技术 一种硅纳米晶/石墨烯宽光谱光电探测器及其制备方法 (Silicon nanocrystal/graphene wide-spectrum photoelectric detector and preparation method thereof ) 是由 王东辰 徐鹏霄 王艳 唐光华 陈鑫龙 戴丽英 杨杰 于 2019-08-30 设计创作，主要内容包括：本发明公开了一种硅纳米晶/石墨烯宽光谱光电探测器及其制备方法,其结构从下到上依次包括背面电极、衬底、硅纳米晶层、石墨烯层和正面电极；背面电极为Ti/Au/Ti电极；衬底为n型Si重掺杂；硅纳米晶层使用氢硅倍半环氧乙烷旋涂并高温退火后得到；石墨烯层为单层石墨烯,蒸镀Au转移获得；正面电极为Ti/Au电极。本发明的光电探测器能够对紫外、可见及近红外光学频谱范围进行响应,经硅纳米晶层与石墨烯层间的光致开关效应实现信号倍增,制备工艺简便,与CMOS工艺兼容。(The invention discloses a silicon nanocrystal/graphene wide-spectrum photoelectric detector and a preparation method thereof, and the structure of the photoelectric detector sequentially comprises a back electrode, a substrate, a silicon nanocrystal layer, a graphene layer and a front electrode from bottom to top; the back electrode is a Ti/Au/Ti electrode; the substrate is heavily doped with n-type Si; the silicon nanocrystalline layer is obtained by using hydrogen silsesquioxane ethylene oxide to spin and anneal at high temperature; the graphene layer is single-layer graphene and is obtained by evaporation Au transfer; the front electrode is a Ti/Au electrode. The photoelectric detector can respond to ultraviolet, visible and near-infrared optical spectrum ranges, realizes signal multiplication through a photoinduced switching effect between the silicon nanocrystalline layer and the graphene layer, and is simple and convenient in preparation process and compatible with a CMOS (complementary metal oxide semiconductor) process.)

1. A silicon nanocrystalline/graphene wide-spectrum photoelectric detector is characterized in that a silicon nanocrystalline layer (3), a graphene layer (2) and a front electrode (1) are sequentially arranged on an n-type Si substrate (4), and a back electrode (5) is arranged below the n-type Si substrate (4);

the resistivity of the n-type Si substrate (4) is 1-10 omega/cm;

the silicon nanocrystalline layer (3) is obtained by spin coating of hydrogen silsesquioxane and high-temperature annealing, and the thickness is 0.5-0.8 mu m;

the front electrode (1) is a Ti/Au electrode and is in contact with the graphene layer (2);

the back electrode (5) is a Ti/Au/Ti electrode and is in contact with the Si substrate (4).

2. The silicon nanocrystal/graphene broad spectrum photodetector as claimed in claim 1, wherein the graphene layer (2) is a single layer structure, a 30-50nm thick gold layer is evaporated on the surface of graphene, and the graphene and gold layer are simultaneously transferred from the copper foil to the silicon nanocrystal layer (3).

3. The silicon nanocrystal/graphene broad spectrum photodetector as claimed in claim 1, wherein the silicon nanocrystal layer (3) is spin-coated with hydrogen silsesquioxane and treated at high temperature, the annealing temperature being 900-.

4. The silicon nanocrystal/graphene broad spectrum photodetector of claim 1, wherein the graphene layer (2) and the silicon nanocrystal layer (3) are contacted with each other and irradiated by an ultraviolet lamp for 1 hour or more.

5. The silicon nanocrystal/graphene broad spectrum photodetector of claim 1, wherein the thickness of Ti/Au/Ti in the back electrode (5) is 20nm/180nm/20nm, respectively.

6. The silicon nanocrystal/graphene broad spectrum photodetector of claim 1, wherein the thickness of Ti/Au in the front electrode (1) is 20nm/300nm, respectively.

7. A preparation method of a silicon nanocrystal/graphene wide spectrum photoelectric detector is characterized by comprising the following steps:

step 1, cleaning an n-type Si substrate;

step 2, preparing a silicon nanocrystalline layer, spin-coating HSQ photoresist with the thickness of 0.5-0.8 μm, and putting the photoresist into a quartz annealing furnace in a nitrogen atmosphere for annealing;

step 3, carrying out first-step photoetching to obtain a silicon nanocrystalline mesa graph, and etching by using ICP (inductively coupled plasma) to obtain a silicon nanocrystalline mesa;

step 4, manufacturing a back electrode layer, and evaporating Ti/Au/Ti by using an electron beam;

step 5, manufacturing a graphene layer, evaporating a 30-50nm Au layer on the graphene layer, and preparing a copper foil corrosive liquid;

step 6, graphene layer transfer, namely, using a Si substrate slice to lift and transfer graphene plated with an Au layer into clear water for soaking, and transferring the graphene to a Si substrate spin-coated with a silicon nanocrystalline layer;

step 7, carrying out secondary photoetching, aligning with the alignment of the mesa graph of the silicon nanocrystalline layer, and photoetching to obtain a graphene mesa graph;

8, corroding the Au layer by using a gold corrosive liquid, and etching by using oxygen plasma to obtain a graphene table top pattern;

step 9, carrying out third photoetching to obtain a front electrode pattern, evaporating the Ti/Au electrode, and soaking and stripping with acetone;

step 10, corroding the table top gold layer by using gold corrosive liquid;

and 11, scribing the Si sheet, and packaging on the tube shell to finish the preparation work of the device.

8. The method for preparing a silicon nanocrystal/graphene wide-spectrum photodetector as claimed in claim 7, wherein the substrate sheet is ultrasonically cleaned by acetone and alcohol in step 1, and dried by nitrogen.

9. The method for preparing a silicon nanocrystal/graphene wide spectrum photodetector as claimed in claim 7, wherein the thickness of Ti/Au/Ti in step 4 is 20nm/180nm/20nm, respectively.

10. The method for preparing a silicon nanocrystal/graphene wide spectrum photodetector as claimed in claim 7, wherein the thickness of the evaporation electrode Ti/Au in step 9 is 20nm/300nm, respectively.

Technical Field

The invention relates to a photoelectric detection technology, in particular to a silicon nanocrystal/graphene wide-spectrum photoelectric detector and a preparation method thereof.

Background

Widening the optical spectrum response range of the photoelectric detector is the most direct and effective way for improving the acquisition and identification capability of detection information, and the traditional method is to simply add the photoelectric detectors responding in different wave bands or extend the spectrum response of the photoelectric devices responding in a certain wave band to two sides, so that the spectrum expansion effect is limited, the requirements on detection component volume and signal processing are greatly increased, and the miniaturization and high-density integration of a system are not facilitated. The wide-spectrum photoelectric detector manufactured by utilizing the characteristic of zero band gap of the graphene material can effectively expand the spectrum range and reduce the volume of a detection assembly, can realize heterogeneous integration of a silicon-based substrate, and is manufactured by utilizing a mature CMOS (complementary metal oxide semiconductor) process.

The light absorption of graphene is weak due to the thickness of the monoatomic layer, so that the detection sensitivity of the device is generally low. In semiconductor quantum dot materials, silicon nanocrystals have the natural advantages of easy silicon-based integration, and the characteristics of low cost, no toxicity, high gain and the like. The prepared photoelectric detector has the advantages of high responsivity, high response speed, ultraviolet, visible and near infrared spectrum response coverage and easiness in silicon-based integration by combining the graphene with the silicon nanocrystals and utilizing the characteristics of extremely high carrier transmission capability of the graphene and higher light absorption efficiency of the silicon nanocrystals.

However, most of the colloidal quantum dot/graphene photoelectric detectors prepared at home and abroad currently use lead sulfide quantum dots, carbon nanotubes and the like to be combined with graphene, and are essentially different from silicon nanocrystal/graphene wide-spectrum photoelectric detectors in device structure and manufacturing process. The colloidal quantum dots use organic macromolecules as dispersing agents to seriously affect the carrier transmission, and the response time reaches the second level. The silicon nanocrystalline material can form silicon nanocrystals embedded in silicon dioxide after high-temperature annealing, the high-density silicon nanocrystals form a carrier transmission channel, electric signal enhancement is realized through an optical switch effect, and the silicon nanocrystalline material has the characteristics of high response speed and spectral response covering ultraviolet, visible and near infrared rays.

Disclosure of Invention

The invention aims to provide a silicon nanocrystal/graphene wide-spectrum photoelectric detector which is high in detection response rate, high in response speed and capable of covering ultraviolet, visible and near infrared spectral responses and a preparation method thereof.

The technical solution for realizing the purpose of the invention is as follows: a silicon nanocrystalline/graphene wide-spectrum photoelectric detector is characterized in that a silicon nanocrystalline layer, a graphene layer and a front electrode are sequentially arranged on an n-type Si substrate, and a back electrode is arranged below the n-type Si substrate;

the resistivity of the n-type Si substrate is 1-10 omega/cm;

the silicon nanocrystalline layer is obtained by spin coating of hydrogen silicon sesqui-oxirane and high-temperature annealing, and the thickness is 0.5-0.8 mu m;

the front electrode is a Ti/Au electrode and is in contact with the graphene layer;

the back electrode is a Ti/Au/Ti electrode and is in contact with the Si substrate.

A preparation method of a silicon nanocrystal/graphene wide spectrum photoelectric detector comprises the following steps:

step 1, cleaning an n-type Si substrate;

step 2, preparing a silicon nanocrystalline layer, spin-coating HSQ photoresist with the thickness of 0.5-0.8 μm, and putting the photoresist into a quartz annealing furnace in a nitrogen atmosphere for annealing;

step 3, carrying out first-step photoetching to obtain a silicon nanocrystalline mesa graph, and etching by using ICP (inductively coupled plasma) to obtain a silicon nanocrystalline mesa;

step 4, manufacturing a back electrode layer, and evaporating Ti/Au/Ti by using an electron beam;

step 5, manufacturing a graphene layer, evaporating a 30-50nm Au layer on the graphene layer, and preparing a copper foil corrosive liquid;

step 6, graphene layer transfer, namely, using a Si substrate slice to lift and transfer graphene plated with an Au layer into clear water for soaking, and transferring the graphene to a Si substrate spin-coated with a silicon nanocrystalline layer;

step 7, carrying out secondary photoetching, aligning with the alignment of the mesa graph of the silicon nanocrystalline layer, and photoetching to obtain a graphene mesa graph;

8, corroding the Au layer by using a gold corrosive liquid, and etching by using oxygen plasma to obtain a graphene table top pattern;

step 9, carrying out third photoetching to form an upper electrode layer pattern, evaporating the Ti/Au electrode, and soaking and stripping with acetone;

step 10, corroding the table top gold layer by using gold corrosive liquid;

and 11, scribing the Si sheet, and packaging on the tube shell to finish the preparation work of the device.

Compared with the prior art, the invention has the advantages that: (1) the structure device can realize response to ultraviolet, visible and near-infrared incident light, realizes signal amplification through an optical switch effect, has high responsivity and high response speed, has spectral response covering ultraviolet, visible and near-infrared, is easy for silicon-based integration, overcomes the defect that colloidal quantum dot carriers cannot be effectively transmitted, and can be used for preparing wide-spectrum and high-responsivity photoelectric detectors; (2) the detector device structure has universality and low manufacturing cost; (3) the photoelectric detector realizes the conversion and amplification of ultraviolet, visible and near-infrared wave band optical signals through the silicon nanocrystalline layer, carriers are transmitted to the graphene layer, the conductivity change of the graphene layer is measured to obtain electric signal output, and the lower electrode of the Si substrate is electrified to realize grid voltage control.

Drawings

Fig. 1 is a schematic structural diagram of a silicon nanocrystal/graphene wide-spectrum photodetector.

Fig. 2 is a flow chart of the preparation of the silicon nanocrystal/graphene wide spectrum photodetector.

Fig. 3 is an optical microscope photograph of a silicon nanocrystal/graphene broad spectrum photodetector.

Detailed Description

The silicon nanocrystal/graphene broad spectrum photoelectric detector capable of detecting ultraviolet waveband to near-infrared waveband provided by the invention sequentially comprises a back electrode 5, an n-type Si substrate 4, a silicon nanocrystal layer 3, a graphene layer 2 and a front electrode 1 from bottom to top.

The n-type Si substrate 4 is sequentially provided with a silicon nanocrystalline layer 3, a graphene layer 2 and a front electrode 1, and a back electrode 5 is arranged below the n-type Si substrate 4;

the resistivity of the n-type Si substrate 4 is 1-10 omega/cm;

the silicon nanocrystalline layer 3 is obtained by spin coating and high-temperature annealing of hydrogen silsesquioxane, and the thickness is 0.5-0.8 μm;

the front electrode 1 is a Ti/Au electrode and is in contact with the graphene layer 2;

the back electrode 5 is a Ti/Au/Ti electrode and is in contact with the Si substrate 4.

The graphene layer 2 is of a single-layer structure, a 30-50nm thick gold layer is evaporated on the surface of the graphene, and the graphene and the gold layer are transferred to the silicon nanocrystalline layer 3 from the copper foil simultaneously.

Further, the silicon nanocrystalline layer 3 is spin-coated with hydrogen silsesquioxane and treated at high temperature, wherein the annealing temperature is 900-.

Further, the graphene layer 2 and the silicon nanocrystalline layer 3 are contacted with each other and are irradiated by an ultraviolet lamp for more than 1 hour.

Further, the thickness of Ti/Au/Ti in the back electrode 5 was 20nm/180nm/20nm, respectively.

Further, the thickness of Ti/Au in the front electrode 1 was 20nm/300nm, respectively.

The invention also provides a preparation method of the silicon nanocrystal/graphene wide-spectrum photoelectric detector, which comprises the following steps:

step 1, cleaning an n-type Si substrate 4;

step 2, preparing a silicon nanocrystalline layer 3, spin-coating HSQ photoresist at a rotating speed of 3000 r/min and a thickness of 0.5-0.8 μm, and annealing in a nitrogen atmosphere of a quartz annealing furnace;

step 3, carrying out first-step photoetching to obtain a silicon nanocrystalline mesa graph, and etching by using ICP (inductively coupled plasma) to obtain a silicon nanocrystalline mesa;

step 4, manufacturing a back electrode layer 5, and evaporating Ti/Au/Ti by using an electron beam;

step 5, manufacturing a graphene layer 2, evaporating a 30-50nm Au layer on the graphene layer, and preparing a copper foil corrosive liquid;

step 6, graphene layer 2 is transferred, the graphene coated with the Au layer is lifted and transferred to clear water by using a Si substrate slice to be soaked, and then the graphene is transferred to a Si substrate coated with a silicon nanocrystalline layer 3 in a spinning mode;

step 7, carrying out secondary photoetching, aligning with the mesa graph of the silicon nanocrystalline layer 3 in an alignment manner, and photoetching to obtain a graphene mesa graph;

8, corroding the Au layer by using a gold corrosive liquid, and etching by using oxygen plasma to obtain a graphene table top pattern;

step 9, carrying out third photoetching to form a pattern of the upper electrode layer 1, evaporating Ti/Au of the electrode, and soaking and stripping with acetone;

step 10, corroding the table top gold layer by using gold corrosive liquid;

and 11, scribing the Si sheet, and packaging on the tube shell to finish the preparation work of the device.

Further, in the step 1, the substrate sheet is ultrasonically cleaned by acetone and alcohol, and is dried by nitrogen.

Further, the thickness of Ti/Au/Ti in step 4 is 20nm/180nm/20nm, respectively.

Further, in step 9, the electrodes Ti/Au were evaporated to a thickness of 20nm/300nm, respectively.

The present invention will be described in detail with reference to examples.