Heterojunction photoelectric detector based on interface defect regulation and preparation method thereof

Abstract

The invention belongs to the field of semiconductors, and particularly discloses a heterojunction photoelectric detector based on interface defect regulation and control and a preparation method thereof, and the heterojunction photoelectric detector based on interface defect regulation and control sequentially comprises a flexible substrate, a perovskite single crystal thin film layer, an artificial defect trapping layer, an indium gallium zinc oxide thin film and a metal electrode from bottom to top. According to the invention, artificial defects are introduced at a perovskite interface, and the concentration of indium gallium zinc oxide carriers is regulated and controlled by utilizing electrons captured by a heterojunction interface through a capacitive coupling effect, so that the contradiction that the response speed and the responsivity cannot coexist in a grating effect gain mechanism of a photoelectric detector is successfully solved, and the response speed and the light current of the device are effectively improved. The device is simple in structure, excellent in performance and wide in application range.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a heterojunction photoelectric detector based on interface defect regulation and a preparation method thereof. Background Art

[0002] With the continuous development of technologies such as 5G, cloud computing, and the Internet of Things, the demand for high-speed, high-sensitivity, and large-capacity photodetectors is growing. In the construction of national information infrastructure, the research of photodetectors is a key link to ensure excellent performance of communication systems and reliable data transmission. At present, many semiconductor materials have been used in photodetectors, including silicon, carbon nanotubes, III-V compounds, and quantum dots, and significant progress has been made in improving light detection performance and device structure design. However, in actual semiconductor devices or materials, due to the limitations of growth, preparation, and processing, interface defects will exist. Interface defects can capture and release electrons and holes, thereby affecting carrier concentration and mobility, resulting in non-ideal transmission of electrons and holes, which will greatly affect the sensitivity and response speed of photodetectors.

[0003] In the field of optoelectronic devices, defect capture can prolong carrier lifetimes, and such devices can exhibit ultra-high responsiveness. However, the photogenerated carriers circulate multiple times in the device channel full of traps before recombination occurs, which inevitably leads to a slow response speed of the device. Although increasing the channel mobility and reducing the carrier transit time can increase the optical gain and responsiveness, the higher carrier concentration will cause the dark current of the device to be too large, resulting in an increase in the static power consumption of the device. Therefore, solving the contradiction between the responsiveness and response speed of optoelectronic devices is a key breakthrough in achieving high-performance photoelectric detection devices.

[0004] Many studies on interface defects have been reported. For example, Jiawen Guo et al. published a WS2 / Ge heterojunction photoelectric device that effectively narrowed the band gap of WS2 and achieved broadband spectral response by regulating sulfur vacancy defects in the paper "Ultrabroadband and High-Detectivity Photodetector Based on WS2 / GeHeterojunction through Defect Engineering and Interface Passivation" (Acs Nano15.10119-10129 (2021)). The responsivity and detectivity of the device were 634.5 mA / W and 4.3×10 11Jones. Although the team regulated the separation, transport and recombination of photogenerated carriers through interface defects, there are still common problems such as low responsiveness, poor sensitivity, complex device structure design and lack of optical gain mechanism. Summary of the invention

[0005] In view of the above-mentioned shortcomings, the present invention provides a heterojunction photodetector based on interface defect regulation and a preparation method thereof. The present invention can circumvent the problem that response speed and responsiveness cannot coexist in the grating gain mechanism of traditional detectors, achieve high sensitivity and rapid detection function, and can be used in many fields such as environmental monitoring and space communication.

[0006] In order to achieve the above-mentioned object, the present invention provides a heterojunction photodetector based on interface defect regulation, which comprises, from bottom to top, a flexible substrate, a perovskite single crystal thin film layer, an artificial defect capture layer, an indium gallium zinc oxygen thin film and a metal electrode.

[0007] According to one aspect of the present invention, the artificial defect trapping layer is introduced on the surface of the perovskite by plasma etching.

[0008] According to one aspect of the present invention, the power of the plasma etching is 5 to 10 W, and the time is 20 to 60 seconds.

[0009] According to one aspect of the present invention, the metal electrode includes a source electrode and a drain electrode.

[0010] According to one aspect of the present invention, the source electrode is a Cr / Au electrode, and the thickness of the Cr / Au electrode is 10-20 / 30-50 nm.

[0011] According to one aspect of the present invention, the thickness of the InGaZnO thin film is 20-30 nm.

[0012] According to one aspect of the present invention, the perovskite single crystal thin film layer is lead organic-inorganic hybrid perovskite, and the thickness of the perovskite single crystal thin film layer is 500-800nm.

[0013] Based on the same inventive concept, the present invention also provides a method for preparing any of the above-mentioned heterojunction photodetectors based on interface defect regulation, comprising the following steps:

[0014] S1. Growing perovskite single crystal thin film layer on flexible substrate using spatial confinement method;

[0015] S2, artificially introducing defects on the upper surface of the perovskite single crystal thin film layer using a plasma etching system;

[0016] S3, using a magnetron sputtering coating system to deposit an indium gallium zinc oxide thin film on the surface of the perovskite after artificially introducing defects;

[0017] S4. Using a metal mask and an electron beam coating system, Cr / Au source and drain electrodes were deposited on the surface of InGaZnO to obtain a heterojunction photodetector based on interface defect regulation.

[0018] According to one aspect of the present invention, the flexible substrate is a polyimide flexible substrate.

[0019] Beneficial effects of the present invention:

[0020] (1) The present invention introduces artificial traps at the perovskite interface and combines them with band matching engineering to effectively increase the channel carrier concentration when illuminated, greatly improving the device's responsiveness. After the illumination is turned off, the electrons captured by the interface traps can quickly enter the depletion region under the action of capacitive coupling, achieving a fast response speed. This invention can solve the problem that response speed and responsiveness cannot coexist in the grating effect mechanism, and effectively improve the performance of the photodetector;

[0021] (2) The large number of electrons captured by the artificial defect capture layer can effectively regulate the InGaZnO channel. There is no need to construct an additional gate electrode to introduce the grating effect mechanism, which simplifies the structure of the grating effect detector and greatly improves the integration of the device. At the same time, the InGaZnO covering the upper layer of the perovskite can also play a role in simple packaging, isolating water and oxygen in the air, making the device more stable in the atmospheric environment. The present invention is simple to operate, low in production cost, superior in performance, and has a wide range of applications;

[0022] (3) In traditional photodetectors, although devices based on the grating effect can provide a higher light response, the response speed is relatively slow. The interface defect-controlled perovskite / indium gallium zinc oxide (IGZO) heterojunction photodetector of the present application can have both high light response and fast response speed. The IGZO film prepared by radio frequency magnetron sputtering in the present application has the advantages of high carrier mobility, good mechanical flexibility, and suitability for large-area preparation, so it can be used as a conductive channel. In addition, due to the difference in Fermi levels, the photogenerated electrons in the perovskite single crystal film will flow to the IGZO film, increasing the carrier density and shortening the carrier transit time. When the light irradiation is removed, the photogenerated electrons captured by the perovskite interface defects can regulate the IGZO channel, allowing the IGZO to quickly enter the depletion region, thereby resulting in a faster response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of a heterojunction photodetector based on interface defect regulation of the present invention;

[0024] Figure 2 It is a schematic diagram of the preparation process of the heterojunction photodetector based on interface defect regulation of the present invention.

[0025] Description of reference numerals:

[0026] 1. Flexible substrate; 2. Perovskite single crystal thin film layer; 3. Artificial defect capture layer; 4. Indium gallium zinc oxide thin film; 5a. Source electrode; 5b. Drain electrode. DETAILED DESCRIPTION

[0027] To make the present invention easier to understand, the present invention is further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professional and technical personnel in the field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by known methods.

[0028] In order to solve the contradiction between the responsivity and response speed of the photoelectric device, the inventor of the present application provides a heterojunction photodetector based on interface defect regulation, such as Figure 1 As shown, from bottom to top, it includes a flexible substrate 1, a perovskite single crystal thin film layer 2, an artificial defect trapping layer 3, an indium gallium zinc oxygen thin film 4 and a metal electrode, and the metal electrode includes a source electrode 5a and a drain electrode 5b.

[0029] In some embodiments of the present application, the artificial defect trapping layer is introduced on the surface of the perovskite by plasma etching.

[0030] In some embodiments of the present application, the power of the plasma etching is 5 to 10 W, and the time is 20 to 60 s.

[0031] In some embodiments of the present application, the source electrode is a Cr / Au electrode, and the thickness of the Cr / Au electrode is 10 to 20 / 30 to 50 nm.

[0032] In some embodiments of the present application, the thickness of the InGaZnO thin film is 20-30 nm.

[0033] In some embodiments of the present application, the perovskite single crystal thin film layer is lead organic-inorganic hybrid perovskite, and the thickness of the perovskite single crystal thin film layer is 500-800nm.

[0034] It should be noted that the thickness of the above-mentioned perovskite single crystal thin film layer is controlled by adjusting the thickness of the two glass substrates.

[0035] The present invention also provides a method for preparing any of the above-mentioned heterojunction photodetectors based on interface defect regulation, such as Figure 2 As shown, the following steps are included:

[0036] S1. Growing perovskite single crystal thin film layer on flexible substrate using spatial confinement method;

[0037] S2, artificially introducing defects on the upper surface of the perovskite single crystal thin film layer using a plasma etching system;

[0038] S3, using a magnetron sputtering coating system to deposit an indium gallium zinc oxide thin film on the surface of the perovskite after artificially introducing defects;

[0039] S4. Using a metal mask and an electron beam coating system, Cr / Au source and drain electrodes were deposited on the surface of InGaZnO to obtain a heterojunction photodetector based on interface defect regulation.

[0040] In some embodiments of the present application, the flexible substrate is a polyimide flexible substrate.

[0041] The following is further described in conjunction with specific embodiments and comparative examples.

[0042] Example 1

[0043] An embodiment of the present invention provides a method for preparing a heterojunction photodetector based on interface defect regulation, comprising the following steps:

[0044] Step 1: Use the spatial confinement method to grow perovskite single crystals on a polyimide (PI) flexible substrate.

[0045] In this embodiment, the preparation and growth process of the perovskite precursor are carried out in a glove box to prevent adverse factors such as water and oxygen in the atmosphere from interfering with the experimental results. The specific steps are as follows:

[0046] (1) Preparation of precursor solution. In this embodiment, the perovskite type selected is FASnI3, which is dissolved in N-N-dimethylamide solvent according to the principle that the molar ratio of FAI and SnI2 is 1:1, stirred and dissolved at 60°C for 2 hours, and then filtered through a filter sieve with a pore size of 0.5 μm to obtain a clean precursor solution without residue.

[0047] (2) Growth of perovskite single crystal thin film by spatial confinement method. In this embodiment, the PI flexible substrate and the glass plate were first placed in acetone, isopropanol, and deionized water in turn and ultrasonicated for 5 minutes each to remove surface impurities; then, the glass sheet was pressed on the PI, and 50 μl of the precursor solution was sucked by a pipette and dropped into the gap between the glass sheet and the substrate; then, the above sample was placed on a hot plate at 40°C and heated for 24 hours to obtain a perovskite single crystal thin film layer 2.

[0048] Step 2: Use plasma to treat the surface of the perovskite single crystal film to obtain artificial defects.

[0049] Specifically, Ar gas is used as a plasma carrier, the gas flow rate is 5 sccm, the power is 10 W, and the processing time is 30 s to obtain artificial defect capture 3.

[0050] Step 3: Deposit an InGaZnO thin film on the surface of the perovskite using magnetron sputtering.

[0051] In this embodiment, when magnetron sputtering is used to prepare InGaZnO, the chamber pressure is 0.75 Pa, the Ar gas flow rate is 12 sccm, the sputtering power is 25 W, the sputtering time is 3 min (the target material is IGZO), and an InGaZnO thin film 4 is obtained.

[0052] Step 4: Use a metal mask to evaporate a metal electrode on top of the InGaZnO film to obtain an electrode layer.

[0053] Comparative Example 1

[0054] The difference between this comparative example and Example 1 is that step 2 is not performed, that is, plasma is not used to treat the surface of the perovskite single crystal film to obtain artificial defects; the other steps and parameters are the same as those in Example 1.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 1 is that step 3 is not performed, that is, magnetron sputtering is not used to deposit an indium gallium zinc oxide thin film layer on the surface of the perovskite; the other steps and parameters are the same as those in Example 1.

[0057] Comparative Example 3

[0058] The difference between this comparative example and Example 1 is that the indium gallium zinc oxide thin film layer in step 3 is replaced by a zinc oxide thin film; the other steps and parameters are the same as those in Example 1.

[0059] Performance testing and result analysis:

[0060] The devices prepared in Example 1 and Comparative Examples 1-3 were tested for photoelectric performance, and the results are shown in Table 1 below:

[0061] Table 1 Comparison of key performance parameters between Example 1 and Comparative Examples 1-3

[0062]

[0063] It can be seen from Table 1 that Example 1 has both a large responsiveness and a fast response speed, which indicates that the interface defect control method of the present application is feasible for controlling the performance of optoelectronic devices.

[0064] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A heterojunction photodetector based on interface defect regulation, It is characterized in that From bottom to top, it includes a flexible substrate, a perovskite single crystal thin film layer, an artificial defect capture layer, an indium gallium zinc oxide thin film and a metal electrode.

2. The heterojunction photodetector based on interface defect regulation according to claim 1, It is characterized in that The artificial defect capture layer is introduced on the surface of the perovskite by plasma etching.

3. The heterojunction photodetector based on interface defect regulation according to claim 2, It is characterized in that The power of the plasma etching is 5 to 10 W, and the time is 20 to 60 seconds.

4. The heterojunction photodetector based on interface defect regulation according to claim 1, It is characterized in that The metal electrodes include a source electrode and a drain electrode.

5. The heterojunction photodetector based on interface defect regulation according to claim 4, It is characterized in that The source electrode is a Cr / Au electrode, and the thickness of the Cr / Au electrode is 10-20 / 30-50 nm.

6. The heterojunction photodetector based on interface defect regulation according to claim 1, It is characterized in that The thickness of the InGaZnO thin film is 20-30 nm.

7. The heterojunction photodetector based on interface defect regulation according to claim 1, It is characterized in that The perovskite single crystal thin film layer is lead organic-inorganic hybrid perovskite, and the thickness of the perovskite single crystal thin film layer is 500-800nm.

8. A method for preparing a heterojunction photodetector based on interface defect regulation according to any one of claims 1 to 7, It is characterized in that The following steps are involved: S1. Growing perovskite single crystal thin film layer on flexible substrate using spatial confinement method; S2, artificially introducing defects on the upper surface of the perovskite single crystal thin film layer using a plasma etching system; S3, using a magnetron sputtering coating system to deposit an indium gallium zinc oxide thin film on the surface of the perovskite after artificially introducing defects; S4. Use a metal mask and electron beam coating system to evaporate Cr / Au source and drain electrodes on the surface of InGaZnO to obtain a heterojunction photodetector based on interface defect regulation.

9. The method for preparing a heterojunction photodetector based on interface defect regulation according to claim 8, It is characterized in that The flexible substrate is a polyimide flexible substrate.

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