阅读说明：本技术 一种异质结紫外探测器及其制备方法 (Heterojunction ultraviolet detector and preparation method thereof ) 是由 刘可为 张超 陈星� 申德振 李炳辉 艾秋 张振中 于 2020-12-29 设计创作，主要内容包括：本发明提供一种异质结紫外探测器,包括：衬底、制备于衬底上的ZnO薄膜层、制备于ZnO薄膜层上的非晶Ga-2O-3薄膜层以及分别制备于非晶Ga-2O-3层和ZnO薄膜层上的接触电极；ZnO薄膜层与非晶Ga-2O-3薄膜层接触面形成ZnO/非晶Ga-2O-3异质结；所述ZnO薄膜层的厚度为50～200nm；所述非晶Ga-2O-3薄膜层的厚度为100～300nm。本发明制得的异质结紫外探测器,低温生长可以改善异质结界面缺陷所带来的性能不理想问题,具备良好的载流子调控特性、响应度和稳定性,并具有自供能特性,表现出出色的紫外探测性能。整个薄膜型异质结器件制造工艺简单,所用材料容易获得,具有广阔的发展前景。(The invention provides a heterojunction ultraviolet detector, comprising: substrate, ZnO thin film layer prepared on substrate and amorphous Ga prepared on ZnO thin film layer 2 O 3 Thin film layer and method for preparing same from amorphous Ga 2 O 3 Contact electrodes on the layer and the ZnO thin film layer; ZnO thin film layer and amorphous Ga 2 O 3 Forming ZnO/amorphous Ga on the contact surface of the thin film layer 2 O 3 A heterojunction; the thickness of the ZnO film layer is 50-200 nm; the amorphous Ga 2 O 3 The thickness of the thin film layer is 100-300 nm. The heterojunction ultraviolet detector prepared by the invention can solve the problem of non-ideal performance caused by heterojunction interface defects due to low-temperature growth, has good carrier regulation and control characteristics, responsivity and stability, has self-energy supply characteristics, and shows excellent ultraviolet detection performance. Machine for finishingThe manufacturing process of the thin film type heterojunction device is simple, and the used materials are easy to obtain and have wide development prospect.)

1. A heterojunction ultraviolet detector, comprising: a substrate (1), a ZnO film layer (2) prepared on the substrate (1), and amorphous Ga prepared on the ZnO film layer (2)₂O₃Film layer(3) Respectively prepared from amorphous Ga₂O₃A contact electrode (4) on the thin film layer (3) and the ZnO thin film layer (2); the ZnO film layer (2) and amorphous Ga₂O₃ZnO/amorphous Ga is formed on the contact surface of the thin film layer (3)₂O₃A heterojunction; the thickness of the ZnO film layer (2) is 100-180 nm; the amorphous Ga₂O₃The thickness of the thin film layer (3) is 150-210 nm.

2. A heterojunction ultraviolet detector according to claim 1, characterized in that said substrate (1) is a sapphire substrate.

3. Heterojunction ultraviolet detector according to claim 1, characterized in that said amorphous Ga₂O₃The area of the thin film layer (3) is smaller than that of the ZnO thin film layer (2).

4. A heterojunction uv detector according to claim 1, wherein the contact electrode (4) layer material is Au; the negative electrode is prepared from amorphous Ga₂O₃The anode is prepared on the ZnO thin film layer (2) on the thin film layer (3); the shape is circular, and the thickness is 10-20 nm.

5. A method for preparing a heterojunction ultraviolet detector is characterized in that,

s1: preparing a sapphire substrate, and growing a ZnO thin film layer (2) on the surface of the substrate (1);

s2: amorphous Ga grows on the surface of the ZnO film layer (2)₂O₃A thin film layer (3), a ZnO thin film layer (2) and amorphous Ga₂O₃The contact surface of the thin film layer (3) forms a heterojunction structure;

s3: in the amorphous Ga₂O₃A contact electrode (4) is formed on the thin film layer (3) and the ZnO thin film layer (2).

6. The method for preparing a heterojunction ultraviolet detector as claimed in claim 5, wherein in step S1, the ZnO thin film layer (2) is prepared by molecular epitaxy technique.

7. The method of claim 5, wherein the amorphous Ga is in step S2₂O₃The preparation method of the thin film layer (3) is a magnetron sputtering technology.

8. The method for preparing a heterojunction ultraviolet detector as claimed in claim 5, wherein the material of the contact electrode (4) layer in step S3 is Au; the negative electrode is prepared from amorphous Ga₂O₃The anode is prepared on the ZnO thin film layer (2) on the thin film layer (3); the shape is round; the preparation method is a magnetron sputtering technology.

Technical Field

The invention relates to the technical field of ultraviolet detection, in particular to a heterojunction ultraviolet detector and a preparation method thereof.

Background

Following laser detection and infrared detection techniques, ultraviolet detection techniques are gradually developed as a new dual-purpose technology for military and civilian use. Ultraviolet detection technology plays an important role in various fields, such as missile early warning, space detection, combustion engineering, ultraviolet monitoring and the like. The wide-forbidden-band semiconductor ultraviolet detector is considered to be a third-generation ultraviolet detector capable of replacing a vacuum photomultiplier and a Si-based photomultiplier due to the advantages of small volume, light weight, no need of an optical filter during working, no need of refrigeration and the like.

Among a plurality of wide bandgap semiconductor materials, a ZnO material as a typical representative has the advantages of rich raw materials, low price, safety, environmental protection and the like. Ga₂O₃The material has ultraviolet light absorption characteristics, and is widely researched in the field of ultraviolet detection due to the appropriate band gap width of the material. ZnO and Ga₂O₃The material can be wide and narrow, so that the material is very suitable for constructing a heterojunction. At present, based on Ga₂O₃The research on the heterojunction type ultraviolet detection of the thin film is mainly crystal Ga grown under the high-temperature condition₂O₃The film is high in growth temperature, the growth quality is influenced by various factors, and the cost is relatively high. The interface of the heterojunction has many problems such as interface defects and unclear interface due to high temperature.

Disclosure of Invention

Aiming at the problems, the invention provides a heterojunction ultraviolet detector and a preparation method thereof. Amorphous Ga₂O₃The material has the advantages of good uniformity, low preparation temperature, easy large-area film formation and the like, so the material has certain application in electricity and optics, and the ZnO/amorphous Ga is constructed by citing the properties of the material₂O₃The heterojunction is favorable for improving the problem of a heterojunction interface of two materials, and further the application prospect of the heterojunction ultraviolet photoelectric detector is researched.

The invention provides a heterojunction ultraviolet detector, comprising: substrate, ZnO thin film layer prepared on substrate and amorphous Ga prepared on ZnO thin film layer₂O₃Thin film layer prepared from amorphous Ga₂O₃Contact electrodes on the thin film layer and the ZnO thin film layer; the thickness of the ZnO film layer is 100-180 nm; the amorphous Ga₂O₃The thickness of the thin film layer is 150-210 nm.

Preferably, the substrate is a sapphire substrate.

Preferably, the amorphous Ga₂O₃The thin film layer covers half of the surface of the ZnO thin film layer.

Preferably, the contact electrode layer material is Au; the negative electrode is prepared from amorphous Ga₂O₃On the layer, the anode is prepared on the ZnO film layer; the shape is circular, and the thickness is 10-20 nm.

The invention also provides a preparation method of the heterojunction ultraviolet detector, which is characterized in that,

s1: preparing a sapphire substrate, and growing a ZnO thin film layer on the surface of the substrate;

s2: growing amorphous Ga on the surface of the ZnO film layer₂O₃The contact surface of the ZnO thin film layer and the amorphous Ga2O3 thin film layer forms a heterojunction structure;

s3: in the amorphous Ga₂O₃And forming a contact electrode on the thin film layer and the ZnO thin film layer.

Preferably, in step S1, the preparation method of the ZnO thin film layer is a molecular epitaxy technique.

Preferably, in step S2,the amorphous Ga₂O₃The preparation method of the thin film layer is a magnetron sputtering technology.

Preferably, the contact electrode layer material in step S3 is Au; the negative electrode is prepared from amorphous Ga₂O₃On the film layer, the anode is prepared on the ZnO film layer; the shape is round, and the preparation method is a magnetron sputtering technology.

The invention can obtain the following beneficial effects:

1. strong process controllability, easy operation and low manufacturing cost.

2. The heterojunction ultraviolet detector prepared by the invention can solve the problem of non-ideal performance caused by heterojunction interface defects due to low-temperature growth, has good carrier regulation and control characteristics, responsivity and stability, has self-energy supply characteristics, and shows excellent ultraviolet detection performance.

3. The whole thin film type heterojunction device is simple in manufacturing process, and the used materials are easy to obtain, so that the thin film type heterojunction device has a wide development prospect.

Drawings

FIG. 1 is a schematic view of a heterojunction ultraviolet detector structure of a heterojunction ultraviolet detector and a preparation method thereof according to the invention;

FIG. 2 is a graph of spectral response characteristics of example 1 of a heterojunction ultraviolet detector and method of making the same of the present invention;

FIG. 3 is a graph showing a current-voltage (I-V) characteristic curve (dark current) in a dark state and a comparison of photocurrent of a device under ultraviolet light in example 1 of a heterojunction ultraviolet detector and a method for manufacturing the same according to the present invention;

fig. 4 is a time response characteristic curve of a heterojunction ultraviolet detector and a method for manufacturing the same of example 1 of the present invention.

Wherein the reference numerals are:

substrate 1, ZnO thin film layer 2, amorphous Ga₂O₃Thin film layer 3, contact electrode 4.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.

The heterojunction ultraviolet detector and the preparation method thereof provided by the invention will be described in detail with reference to the following embodiments.

Fig. 1 is a schematic structural diagram of a heterojunction ultraviolet detector and a preparation method thereof according to the invention.

As shown in fig. 1, the present invention provides a heterojunction ultraviolet detector comprising: substrate 1, ZnO thin film layer 2 prepared on the substrate, and amorphous Ga prepared on the ZnO thin film layer 2₂O₃Thin film layer 3 prepared from amorphous Ga₂O₃A contact electrode 4 on the thin film layer 3 and the ZnO thin film layer 2; the thickness of the ZnO film layer 2 is 100-180 nm; amorphous Ga₂O₃The thickness of the thin film layer 3 is 150-210 nm.

Wherein, the substrate 1 is a sapphire substrate; amorphous Ga₂O₃The thin film layer 3 covers half of the surface of the ZnO thin film layer 2; the contact electrode 4 layer is made of Au; the negative electrode is prepared from amorphous Ga₂O₃On the film layer 3, the anode is prepared on the ZnO film layer 2; the shape is circular, and the thickness is 10-20 nm.

Example 1

And preparing the ZnO film on the sapphire substrate by adopting a Molecular Beam Epitaxy (MBE) technology. The Zn source temperature is controlled at 230 ℃, the substrate 1 temperature is kept at 450 ℃, and the radio frequency power is 280W, O₂The flow rate is 1.4sccm, the growth time is 40min, and the thickness of the thin film layer is about 100 nm.

After the ZnO film layer 2 on the sapphire substrate is partially shielded, the sapphire substrate is put into a deposition chamber, and amorphous Ga grows on the deposition chamber by adopting a magnetron sputtering method₂O₃Film of Ga₂O₃The purity of the ceramic target material is 99.99 percent, and the specific growth parameters of the magnetron sputtering technology are that the working atmosphere is argon, the working pressure is 2Pa, and the vacuum pressure of the back bottom is less than 1 multiplied by 10^-4Pa, the temperature of the substrate 1 is room temperature, the sputtering power is 60W, the sputtering time is 90min, and the obtained amorphous Ga₂O₃The thickness of the thin film layer 3 is about 150 nm.

Preparing a device electrode: using a mask and adopting a magnetron sputtering technology to form a ZnO film and amorphous Ga₂O₃An Au film is deposited on the film to be used as a measuring electrode. It is characterized in that in the step, the Au film is annealed for 5 minutes in argon atmosphere, the annealing temperature is 300 ℃, and the diameter of the circular electrode is about 1.2mm

As shown in FIG. 1, ZnO/amorphous Ga prepared by the above experimental process₂O₃A heterojunction ultraviolet detector, comprising in sequence sapphire as substrate 1; a ZnO thin film layer 2 provided on the substrate 1; amorphous Ga disposed on the ZnO thin film layer 2₂O₃A thin film layer 3; is arranged on amorphous Ga₂O₃Electrode Au on thin film layer 3. ZnO thin film and amorphous Ga₂O₃Forming ZnO/amorphous Ga on the contact surface of the film₂O₃A heterojunction.

FIG. 2 is a graph of spectral response characteristics of the heterojunction UV detector prepared in example 1 of the present invention, and it can be seen that ZnO/amorphous Ga₂O₃The heterojunction is only capable of producing an optical response to 254nm light. The response peak value of the device is 246nm, the responsivity is 0.196A/W, and the solar blind ultraviolet detection device has good solar blind ultraviolet detection performance.

Fig. 3 shows that the heterojunction ultraviolet detector prepared in embodiment 1 of the present invention is used for testing I-V characteristic curve (dark current) in a dark state and photocurrent of a device under 254nm illumination, and it can be seen from fig. 3 that the device prepared in the present invention has a good rectification characteristic and a low dark current. Under the bias of 10V, the current is rapidly increased to 175nA after being irradiated by ultraviolet light with the wavelength of 254nm, and the light-dark ratio I₂₅₄/I_darkIs 1.12X 10⁴The magnitude order shows that the device has better response to 254nm ultraviolet light.

FIG. 4 shows the I-t curve measured by turning the lamp off without turning the lamp on under UV illumination at 254nm at a bias of 0V. The ZnO/amorphous Ga₂O₃The heterojunction ultraviolet detector has the characteristic of self-energizing under 0V bias voltage. In the embodiment, a plurality of cycles are repeated, and the device has good repeatability. In a dark state and after irradiation of ultraviolet light at 254nm, the current rapidly increases, and the light-dark ratio I₂₅₄/I_darkIs 3.64X 10³In order of magnitude.

Example 2

And preparing the ZnO film on the c-plane sapphire substrate by adopting a Molecular Beam Epitaxy (MBE) technology. The Zn source temperature is controlled at 230 ℃, the substrate temperature is kept at 450 ℃, and the radio frequency power is 280W, O₂The flow rate is 1.4sccm, and the thickness of the thin film layer is about 140nm after 60min of growth.

After the ZnO film layer 2 on the sapphire substrate is partially shielded, the sapphire substrate is put into a deposition chamber, and amorphous Ga grows on the deposition chamber by adopting a magnetron sputtering method₂O₃Film of Ga₂O₃The purity of the ceramic target material is 99.99 percent, and the specific growth parameters of the magnetron sputtering technology are that the working atmosphere is argon, the working pressure is 2Pa, and the vacuum pressure of the back bottom is less than 1 multiplied by 10^-4Pa, the temperature of the substrate 1 is room temperature, the sputtering power is 60W, the sputtering time is 110min, and the obtained amorphous Ga₂O₃The thickness of the thin film layer 3 is about 180 nm.

Preparing a device electrode: using a mask and adopting a magnetron sputtering technology to form a ZnO film and amorphous Ga₂O₃An Au film is deposited on the film to be used as a measuring electrode. It is characterized in that in the step, the Au film is annealed for 5 minutes in argon atmosphere, the annealing temperature is 300 ℃, and the diameter of the circular electrode is about 1.2mm

Example 3

And preparing the ZnO film on the c-plane sapphire substrate by adopting a Molecular Beam Epitaxy (MBE) technology. The Zn source temperature is controlled at 230 ℃, the substrate 1 temperature is kept at 450 ℃, and the radio frequency power is 280W, O₂The flow rate is 1.4sccm, and the thickness of the thin film layer is about 180nm after 80min of growth.

After the ZnO film layer 2 on the sapphire substrate is partially shielded, the sapphire substrate is put into a deposition chamber, and amorphous Ga grows on the deposition chamber by adopting a magnetron sputtering method₂O₃Film of Ga₂O₃The purity of the ceramic target material is 99.99 percent, and the specific growth parameters of the magnetron sputtering technology are that the working atmosphere is argon, the working pressure is 2Pa, and the vacuum pressure of the back bottom is less than 1 multiplied by 10^-4Pa, the temperature of the substrate 1 is room temperature, and the sputtering power is 60WThe time is 130min, and the obtained amorphous Ga₂O₃The thickness of the thin film layer 3 is about 210 nm.

Preparing a device electrode: using a mask and adopting a magnetron sputtering technology to form a ZnO film and amorphous Ga₂O₃An Au film is deposited on the film to be used as a measuring electrode. It is characterized in that in the step, the Au film is annealed for 5 minutes in argon atmosphere, the annealing temperature is 300 ℃, and the diameter of the circular electrode is about 1.2mm

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

The above embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.