CN116705890A - Self-powered broad-spectrum weak light signal detection photoelectric detection device and preparation method thereof - Google Patents

Abstract

The invention discloses a self-powered broad-spectrum weak light signal detection photoelectric detection device and a preparation method thereof. The method comprises the following steps: si is selected as a substrate; depositing a ZnO film by using a direct current magnetron sputtering technology; depositing an ITO electrode layer on the surface of the ZnO film; spin-coating an In electrode on the back surface of the Si substrate; based on the coupling effect of the ZnO nano rod array structure and the pyroelectric semiconductor, the device has obvious self-driven ultrahigh light response to the wavelength range of 405nm-1550nm, and realizes the detection of weak light signals of visible light and near infrared light. The photoelectric detection device has the advantages of high responsivity, high detection rate, high response speed, good cycle stability and the like; the preparation process is simple, nontoxic and pollution-free, has higher product quality, is suitable for large-scale industrial production, and has great application prospect in the field of high-performance weak light photoelectric detection devices.

Description

A self-powered wide-spectrum weak light signal detection photodetector device and its preparation method

technical field

The invention relates to a self-powered wide-spectrum weak light signal detection photodetection device and a preparation method thereof, in particular to a Si/ZnO heterojunction structure photodetection device and a preparation method thereof, belonging to the field of semiconductor optoelectronic devices.

Background technique

In recent years, the self-powered wide-spectrum weak light signal detection photodetection device has attracted widespread attention at home and abroad, because this kind of weak light signal detection requires the device to have higher sensitivity and detection rate, so that the detection device can operate at low power. Work under dense light sources. The self-powered photodetection device reduces energy cost and complexity of circuit design, realizes energy saving and environmental protection, and reduces environmental pollution. In addition, wide-spectrum detection realizes the detection of optical signals in multiple bands, which improves the selectivity of the device for optical transmission and reception.

But at present, the existing semiconductor photodetectors have too high background carrier density, large dark current, and low detection rate, which limit the detection of weak light signals. Moreover, due to the influence of the bandgap width of the material itself, the response range Relatively single, the response speed is relatively slow, which reduces the photoelectric conversion efficiency and limits the application range of the device.

For example:

Chinese patent application CN114671626A discloses a ZnO quantum dot/magnetron sputtering ZnO homojunction ultraviolet photodetector and its preparation method.

Chinese patent application CN113299537B discloses an integrated narrow-frame photodetector and a manufacturing method thereof. The method adopts a CVD method to improve detection efficiency and response rate of the device.

Chinese patent application CN115332385A discloses an infrared avalanche photodetector based on a macro-assembled graphene/epitaxial silicon Schottky junction and its preparation method, which realizes sensitive detection of weak light signals.

However, most of the ZnO-based photodetection devices disclosed above have a photoresponse function to ultraviolet light, cannot realize photodetection in a wide range of ultraviolet-visible-near-infrared bands, and are weak in detecting weak light signals.

How to develop a semiconductor material with a wide-band photoresponse, and on this basis, further develop a self-powered photodetector that detects weak light signals has become an urgent need for technicians in the field of semiconductor materials and devices. Solved technical problems.

Contents of the invention

One of the objectives of the present invention is to provide a self-powered broadband Si/ZnO heterojunction photodetection device for weak optical signal detection.

The technical problem that the present invention needs to solve in order to achieve the above object is how to improve the internal structure of the material used in the photodetector device, break through the limitation of the band gap of the semiconductor material, and broaden the photoresponse band from ultraviolet to near infrared; that is, by preparing ZnO nanorod arrays to form ITO -ZnO/Si-In device structure, using the nanorod array mechanism to achieve high light absorption of the device; using the unique pyroelectric effect of ZnO material to form a high-efficiency conversion of light-heat-electricity-multi-physics field coupling, generating temperature in the device The difference changes, so that the current in the device changes accordingly, and the device detects light; the dark current of the heterojunction is suppressed by using the barrier interface coupled with Si, and the device detects the weak light signal.

The technical solution adopted by the present invention to achieve the above object is a self-powered wide-spectrum weak light signal detection photodetection device, which is characterized in that it includes an In bottom electrode layer, a Si single crystal substrate, and a ZnO thin film from bottom to top. layer and ITO upper electrode layer; where:

The Si single crystal substrate is the base, and its thickness is 0.2mm;

The ZnO thin film layer is deposited on the surface of the substrate by DC magnetron sputtering technology, which has a nanorod structure and a thickness of 400-450nm;

The ITO upper electrode layer is deposited on the surface of the above-mentioned ZnO thin film layer by DC magnetron sputtering technology, and its thickness is 50-100nm;

The In bottom electrode layer is hot-melt spin-coated on the back of the Si substrate, and its thickness is 0.1-0.5mm;

The technical effect directly brought by the above technical solution is to start from the two aspects of preparation materials and structure, that is, by forming a unique pyroelectric effect in the ZnO film that is different from traditional semiconductors, and realize the coupled conversion of light-heat-electricity multi-physics field , this effect does not depend on the bandgap range of semiconductor materials, making breakthroughs in photodetectors in different wavelength ranges from ultraviolet to near infrared;

After testing, the ITO-ZnO/Si-In photodetector device of the above-mentioned technical scheme has a strong light detection capability in the ultra-wide wavelength range of 405nm-1550nm, and when λ=405nm and P=500nW/ ^cm2 , the responsivity is 550.6mA/W, the response speed is 0.13ms;

Moreover, unlike traditional semiconductor photodetection devices, the photodetection process of this device does not require any external bias voltage to drive the operation, and it has a self-powered effect under zero bias voltage. Reduce energy costs to a great extent, enhance the simplification of circuit design, and improve the integration of devices;

In addition, the photodetector device has a relatively high detectivity of 7.7×10 ¹² Jones and realizes the detection of 1 μW/cm ² weak light signals of 405nm visible light and 980nm near-infrared light.

In order to better understand the above technical solution, the principle is explained in detail:

1. The technical effect achieved by the use of ZnO semiconductor thin film layer has three aspects: (1) has the structural characteristics of specific surface area, which enhances the interaction between light and matter; (2) has a unique pyroelectric effect, which can enhance photoelectric detection Light-heat-electric conversion of the device; (3) a large number of grain boundaries between nanorods suppress the thermal diffusion in the plane, increase the transient temperature gradient, and enhance the pyroelectric effect in the ZnO film; (4) the interface potential The formation of the barrier effectively reduces the dark current and improves the device's ability to detect low laser power; (5) as an oxide semiconductor device, it can work effectively in the air environment for a long time, and is durable and stable.

2. In the above technical solution, the main reasons for using 50-100nm ITO conductive glass as the upper electrode are: (1) ITO conductive glass has strong electrical and thermal conductivity and ultra-high transmittance, and can maintain a relatively high temperature in the air environment. Good electron collection ability and strong light transmission and thermal conductivity; (2) The ohmic contact is formed between the ITO conductive glass and the film to promote the transportation of photogenerated carriers.

Experiments have proved that the self-powered wide-spectrum weak light signal detection photodetector device of the above technical scheme has the advantages of self-driving, wide light response band, high responsivity, fast response speed, high low-light signal detection rate, and high stability.

The second object of the present invention is to provide a method for preparing the above-mentioned self-powered wide-spectrum weak light signal detection photodetector device, which has a simple process, high yield, energy saving and environmental protection, and meets the needs of wide-spectrum weak light signal detection. Suitable for large-scale industrial production.

The technical solution adopted by the present invention to achieve the above object is a preparation method of a self-powered wide-spectrum weak light signal detection photodetector device, which is characterized in that it includes the following steps:

The first step, pretreatment steps of Si single crystal substrate:

The Si single crystal substrate was ultrasonically cleaned in alcohol, acetone and alcohol for 3 minutes in sequence; after taking it out, it was blown dry with high-purity nitrogen.

The second step, the deposition step of ZnO thin film layer:

Put the above-mentioned pretreated Si single crystal substrate into the tray, and put it into the vacuum chamber, pump the vacuum chamber to the first high vacuum, adjust the mixed pressure of argon and oxygen to the first pressure of 0.1-1.0Pa, The ratio of argon to oxygen is 20:5, the Si single crystal substrate is adjusted to the first temperature of 500-550°C, and the radio frequency magnetron sputtering technology is used to bombard the ZnO target with ionized particles, and the Si single crystal substrate A thin layer of ZnO is deposited on the surface.

The third step, the deposition step of the electrode on the ITO:

After the sample is taken out from the vacuum chamber, the surface is covered with a mask sheet having a circular hole structure, and the diameter of the circular hole is 50 μm-0.5 mm. Then place the sample on the tray and put it into the vacuum chamber, and pump the vacuum chamber to the second high vacuum; adjust the temperature of the above-mentioned sample covered with the mask sheet to the second temperature of 200-250 °C, and argon pressure Adjust to the second pressure of 0.1-1.0Pa, adopt DC magnetron sputtering technology, under the condition of constant 20W sputtering power, use ionized ions to bombard the ITO target, and deposit a layer on the surface of the above-mentioned ZnO thin film layer ITO electrode layer.

The fourth step, the spin-coating step of the In bottom electrode:

Heating to 150-200°C with an electric soldering iron, melting metal indium wire, and evenly spin-coating it on the back side of the above-mentioned Si single crystal substrate.

3. The preparation method of self-powered wide-spectrum weak light signal detection photodetection device according to claim 2, characterized in that the purity of the argon gas is above 99.999%;

The film growth substrate is a Si single crystal substrate with (100) crystal plane orientation;

The purity of the ZnO target is 99.9%;

The purity of the ITO target material is 99.99%;

The target base distance of the ZnO target and the ITO target are both 35 mm.

4. The preparation method of self-powered wide-spectrum weak light signal detection photodetection device according to claim 2, characterized in that, the first temperature is 500-550°C, and the first high vacuum is 1×10 ^-4 -5×10 ^-4 Pa, the first pressure is 0.1-1.0 Pa.

5. The preparation method of self-powered wide-spectrum weak light signal detection photodetection device according to claim 2, characterized in that, the second temperature is 200-250°C, and the second high vacuum is 1 ×10 ^-4 -5×10 ^-4 Pa, the second pressure is 0.1-1.0Pa.

Preferably, the purity of the argon is above 99.999%;

The film growth substrate is a Si single crystal substrate with (100) crystal plane orientation;

The purity of the ZnO target is 99.9%;

The purity of the ITO target material is 99.99%;

The target base distance of the ZnO target and the ITO target is 35mm;

The technical effect directly brought by this technical solution is that the distance can not only meet the sufficient collision between the ions and the working gas to reduce the kinetic energy during the movement, but also ensure that the ions have sufficient adhesion during the film formation process;

Further preferably, the first temperature is 550°C, the first high vacuum is 5×10 ^-4 Pa, and the first pressure is 0.6 Pa.

The technical effect directly brought by this technical solution is that it can not only improve the crystal quality and purity of the ZnO thin film, but also satisfy the sufficient adhesion of ions in the film formation process and grow high-quality nanorod structures;

Further preferably, the second temperature is 200°C, the second high vacuum is 5×10 ^-4 Pa, and the second pressure is 1.0 Pa;

The technical effect directly brought by this technical solution is to further improve the film-forming quality of the ITO electrode, increase the crystallinity of the film, and ensure that the ITO has sufficient adhesion during the film-forming process.

The technical effect directly brought by the above technical solution is that the process is simple, the yield is high, and it is suitable for large-scale industrial production, and the above preparation method does not use toxic and harmful raw materials, does not generate toxic and harmful waste or exhaust gas, and the entire process is green and energy-saving. Environmental protection, no pollution.

In summary, compared with the prior art, the present invention has the following beneficial effects:

1. The photodetector device with ITO-ZnO/Si-In structure of the present invention has the advantages of self-driving, wide optical response band, high responsivity, fast response speed, high low-light signal detection rate, high stability, etc., and can be used in wide Spectrum weak light signal detection.

The ITO-ZnO/Si-In photodetector device of the present invention has obvious photoresponse characteristics in the 405nm-1550nm wavelength range under the application of zero bias voltage: wherein, when λ=405nm, P=500nW/ ^cm , The responsivity is 550.6mA/W, the detection rate is as high as 7.7×10 ¹² Jones, and the response speed is 0.13ms.

2. The preparation method of the photodetector device has the characteristics of simple process, convenient parameter control, high yield, suitable for large-scale industrial production, low manufacturing cost, energy saving, green environmental protection, and stable product quality.

Description of drawings

Fig. 1 is the schematic diagram of the structure of the ITO-ZnO/Si-In photodetector device made;

Fig. 2 is the X-ray diffraction pattern of ZnO film made in the embodiment;

Fig. 3 is the IV curve of the ITO-ZnO/Si-In photodetector device made in the embodiment under 405nm visible light irradiation and dark condition;

Fig. 4 is the dynamic response curve of the ITO-ZnO/Si-In photodetector device made in the embodiment under no bias voltage, 405nm laser 1.0 μm/ ^cm weak light signal irradiation;

Fig. 5 is the dynamic response curve of the ITO-ZnO/Si-In photodetector device made in the embodiment under no bias voltage, 980nm laser 1.0 μm/ ^cm weak light signal irradiation;

Fig. 6 is the dynamic response curve of the ITO-ZnO/Si-In photodetector device prepared in the embodiment under no bias voltage, 355nm, 1550nm laser irradiation.

Detailed ways

The present invention will be described in detail below in conjunction with the embodiments and accompanying drawings.

The preparation method is as follows:

(1) Pretreatment steps of Si substrate:

The Si single crystal substrate was ultrasonically cleaned in alcohol, acetone and alcohol for 3 minutes in sequence; after taking it out, it was blown dry with high-purity nitrogen.

(2) The preparation steps of ZnO film layer:

Put the above-mentioned Si single crystal substrate cleaned and dried by high-purity nitrogen into the tray, and put it into the vacuum chamber, pump the vacuum chamber to 5×10 ^-4 Pa, and adjust the mixed pressure of argon and oxygen to The pressure is 0.6Pa, the argon-oxygen ratio is 20:5, the Si single crystal substrate is adjusted to a temperature of 550°C, and the radio frequency magnetron sputtering technology is used to bombard the ZnO target with ionized particles. On the surface of the sheet, a thin layer of ZnO was deposited.

(3) Deposition steps of the ITO upper electrode:

After the sample is taken out from the vacuum chamber, the surface is covered with a mask sheet having a circular hole structure, and the diameter of the circular hole is 50 μm-0.5 mm. Then place the sample on a tray and put it into a vacuum chamber, and pump the vacuum chamber to 5×10 ^-4 Pa; adjust the temperature of the above-mentioned sample covered with a mask sheet to 200°C, and adjust the argon gas pressure to 1.0 Pa, using DC magnetron sputtering technology, under constant 20W sputtering power conditions, using ionized ions to bombard the ITO target, and deposit an ITO electrode layer on the surface of the above ZnO thin film layer.

(4) Spin coating steps of In bottom electrode:

Heat it to 150-200°C with an electric soldering iron, melt the metal indium wire, apply it evenly on the back of the Si single crystal substrate of the above sample, and use it as the lower electrode.

After testing, the prepared ITO-ZnO/Si-In photodetector device has obvious photoresponse characteristics in the wavelength range of 405nm-1550nm under the application of zero bias voltage: where, at λ=405nm, P=500nW/ At cm ² , the responsivity is 550.6mA/W, the detection rate is as high as 7.7×10 ¹² Jones, and the response speed is 0.13ms.

Below in conjunction with the accompanying drawings, the test results are described in detail as follows:

Fig. 1 is the schematic diagram of the structure of the ITO-ZnO/Si-In photodetector device made;

As shown in the figure, Si is used as a substrate, a ZnO film layer is placed on the surface of the substrate, and ITO is placed on the surface of the ZnO film layer as an upper electrode. In is placed on the lower surface of the Si substrate as a bottom electrode.

Fig. 2 is the X-ray diffraction pattern of ZnO film made in the embodiment;

As shown in the figure, there is only one ZnO(002) crystal plane with a diffraction peak of 34.32°. Therefore, our prepared ZnO has a single crystal structure with a preferred orientation of the C-axis.

Fig. 3 is the IV curve of the ITO-ZnO/Si-In photodetector device made in the embodiment under 405nm visible light irradiation and dark condition;

As shown in the figure, the device has obvious rectification on the surface and has self-powered characteristics.

Fig. 4 is the dynamic response curve of the ITO-ZnO/Si-In photodetector device made in the embodiment under no bias voltage, 405nm laser 1.0 μm/ ^cm weak light signal irradiation;

As shown in the figure, under no external voltage, the photoresponse has the unique four-stage pyroelectric characteristics of ZnO; and the response period is stable, realizing a self-driven fast photoresponse; there is still an obvious response to weak light signals in the visible range feature.

Fig. 5 is the dynamic response curve of the ITO-ZnO/Si-In photodetector device made in the embodiment under no bias voltage, 980nm laser 1.0 μm/ ^cm weak light signal irradiation;

As shown in the figure, there are still obvious response characteristics to weak light signals in the near-infrared range without an external voltage.

Fig. 6 is the dynamic response curve of the ITO-ZnO/Si-In photodetector device prepared in the embodiment under no bias voltage, 355nm, 1550nm laser irradiation.

As shown in the figure, the device has obvious four-stage rapid and stable photoresponse characteristics for incident light of ultraviolet 355nm and near-infrared 1500nm.

Claims (5)

1. A self-powered wide-spectrum weak light signal detection photodetector device and preparation method thereof, is characterized in that, the longitudinal layered superimposition structure comprises In bottom electrode layer, Si single crystal substrate, ZnO film layer successively from bottom to top and ITO upper electrode layer; where: The Si single crystal substrate is a coating substrate; The ZnO thin film layer is deposited on the surface of the above-mentioned substrate by DC magnetron sputtering technology, and has a nanorod structure with a thickness of ~400-450nm; The ITO upper electrode layer is deposited on the surface of the above-mentioned ZnO thin film layer by DC magnetron sputtering technology; The In bottom electrode layer is spin-coated on the back of the above-mentioned Si substrate by an electric soldering iron. 2. A preparation method of a self-powered wide-spectrum weak light signal detection photodetector device as claimed in claim 1, characterized in that, comprising the following steps: The first step, pretreatment steps of Si single crystal substrate: Put the Si single crystal substrate into alcohol, acetone and alcohol for 3 minutes and ultrasonically clean it; after taking it out, dry it with high-purity nitrogen; The second step, the deposition step of ZnO thin film layer: Put the above-mentioned Si single crystal substrate cleaned and dried by high-purity nitrogen into the tray, and put it into the vacuum chamber, pump the vacuum chamber to the first high vacuum, and adjust the mixed pressure of argon and oxygen to the first The pressure is 0.1-1.0Pa, the argon-oxygen ratio is 20:5, the Si single crystal substrate is adjusted to the first temperature of 500-550°C, and the radio frequency magnetron sputtering technology is used to bombard the ZnO target with ionized particles. On the surface of the Si single crystal substrate, a layer of ZnO film layer is deposited; The third step, the deposition step of the electrode on the ITO: After the sample is taken out from the vacuum chamber, the surface is covered with a mask sheet having a circular hole structure, and the diameter of the circular hole is 50 μm-0.5 mm. Then place the sample on the tray and put it into the vacuum chamber, and pump the vacuum chamber to the second high vacuum; adjust the temperature of the above-mentioned sample covered with the mask sheet to the second temperature of 200-250 °C, and argon pressure Adjust to the second pressure of 0.1-1.0Pa, adopt DC magnetron sputtering technology, under the condition of constant 20W sputtering power, use ionized ions to bombard the ITO target, and deposit a layer on the surface of the above-mentioned ZnO thin film layer ITO electrode layer. The fourth step, the spin-coating step of the In bottom electrode: Use an electric soldering iron to heat to 150-200° C., melt the metal indium wire, and spread it evenly on the back of the Si single crystal substrate of the above sample, to obtain the finished product. 3. The preparation method of self-powered wide-spectrum weak light signal detection photodetector device according to claim 2, characterized in that, the purity of the argon is above 99.999%; The film growth substrate is a Si single crystal substrate with (100) crystal plane orientation; The purity of the ZnO target is 99.9%; The purity of the ITO target material is 99.99%; The target base distance of the ZnO target and the ITO target are both 35 mm. 4. The preparation method of self-powered wide-spectrum weak light signal detection photodetector device according to claim 2, characterized in that, the first temperature is 500-550°C, and the first high vacuum is 1×10 ^-4 -5×10 ^-4 Pa, the first pressure is 0.1-1.0 Pa. 5. The preparation method of the self-powered wide-spectrum weak light signal detection photodetector device according to claim 2, characterized in that, the second temperature is 200-250°C, and the second high vacuum is 1 ×10 ^-4 -5×10 ^-4 Pa, the second pressure is 0.1-1.0Pa.