BiSe-based flexible detector and preparation method thereof

Abstract

The invention provides a preparation method of a flexible detector based on BiSe. The preparation method comprises the following steps: firstly, manufacturing an interdigital electrode serving as a growth substrate; taking Bi2Se3 powder as a growth source, and placing the Bi2Se3 powder in chemical vapor deposition equipment; the interdigital electrode is placed in chemical vapor deposition equipment, and metal on the interdigital electrode is covered and protected; and finally, growing a BiSe thin film on the flexible substrate through a chemical vapor deposition method to obtain the BiSe flexible detector. The method is simple in step, easy to operate and popularize, high in product purity, capable of achieving rapid and large-scale preparation and small in environmental pollution.

Description

Technical Field

[0001] The present invention relates to the field of preparation of infrared detection devices. Background Art

[0002] Traditional inorganic photodetectors (PDs) are mechanically rigid sensors, usually limited by mechanical rigidity, small area, weak absorption efficiency, and fixed bandgap, and are difficult to be applied to scenarios such as wearable devices that require flexible devices.

[0003] Flexible infrared detectors have broad application prospects in wearable devices, biomedicine, and automatic control processes due to their special conformal attachment characteristics. However, the existing flexible infrared detectors have the following problems:

[0004] 1. Preparation cost and process complexity: Although two-dimensional material-based flexible short-wave infrared detectors have excellent optoelectronic properties and mechanical flexibility, their preparation cost is relatively high, and the device performance is restricted by problems such as the intrinsic defects of the materials and contact resistance.

[0005] 2. Limitations of organic semiconductor material properties: Organic semiconductor materials have the advantages of solution processability, low cost, and large-area preparation, but their carrier mobility and light absorption ability are usually low, which limits the device performance.

[0006] 3. Stability and preparation challenges of detectors: Quantum dot (CQD) detectors have advantages such as tunable bandgap, high absorption coefficient, and solution processability, but usually require complex ligand exchange and passivation treatments to improve the device performance and stability.

[0007] 4. Challenges in flexible transformation of traditional semiconductor materials: Transferring traditional long-wave infrared detector materials onto flexible substrates is difficult to ensure the reliability and stability of the devices.

[0008] 5. Problem of balancing performance and stability: While improving the device performance, how to ensure its long-term stability under mechanical deformations such as bending and stretching is still a difficult problem to be solved.

[0009] 6. Dark current and noise problems: InGaAs / InP APDs have problems such as large dark counts, afterpulses, and noise, and the large photosensitive area is an important factor affecting the device performance. How to solve the problem of reducing the photosensitive area of the device without reducing the quantum efficiency is the key to improving the device performance. Summary of the Invention

[0010] The object of the present invention is to provide a preparation method based on a BiSe flexible detector, which is characterized by including the following steps:

[0011] 1) Fabricate interdigital electrodes as the growth substrate;

[0012] 2) Place the Bi2Se3 powder as the growth source in a chemical vapor deposition device; place the interdigital electrodes in the chemical vapor deposition device;

[0013] 3) Grow a BiSe thin film on a flexible substrate by chemical vapor deposition to obtain a flexible BiSe infrared detector.

[0014] Further, in step 1), use polyimide, i.e., PI, as the flexible insulating substrate of the interdigital electrodes, and fabricate Au electrodes on the flexible substrate to form the interdigital electrodes.

[0015] Further, in step 2), place the Bi2Se3 powder in a tube furnace, and the substrate growth position is at the end of the gas flow direction.

[0016] Further, in step 2), during deposition, protect the electrode contacts. Further, place a quartz sheet with a thickness of 1 mm to cover the bottom square electrode where needles need to be inserted during testing, and do not cover the other Au electrodes. During the deposition process, BiSe is deposited not only in the grooves between the Au electrodes but also on the upper surface of the cross electrodes to form a thin film.

[0017] Further, in step 3), after evacuating the inside of the quartz tube, introduce the carrier gas Ar, regulate the gas flow rate and the internal pressure, heat until the reaction is completed, and take out the BiSe detector based on the interdigital electrodes after cooling.

[0018] The technical effects of the present invention are beyond doubt: The BiSe thin film Darwin process is grown on a flexible substrate by chemical vapor deposition. The steps are simple, easy to operate and promote, the product purity is high, it can be prepared quickly and in large quantities, and the environmental pollution is small. Therefore, it has important research value and broad application prospects. Brief Description of the Drawings

[0019] Figure 1 It is an electron microscope image with a magnification of 10000× of the product of the present invention;

[0020] Figure 2 The test result of EDS for the prepared BiSe detector;

[0021] Figure 3 Microscopic schematic diagram of the device structure;

[0022] Figure 4 Growth schematic diagram;

[0023] Figure 5 Physical diagram of the interdigital electrodes;

[0024] Figure 6 XRD characterization of the prepared BiSe detector.

[0025] Figure 7TEM characterization;

[0026] Figure 8 BiSe detector IT. Detailed implementation manners

[0027] The present invention will be further described below in conjunction with embodiments, but it should not be understood that the above-mentioned subject matter scope of the present invention is limited to the following embodiments. Without departing from the above technical idea of the present invention, various substitutions and changes made according to common general technical knowledge and conventional means in the art shall be included within the protection scope of the present invention.

[0028] A preparation method of a BiSe flexible detector, characterized by comprising the following steps:

[0029] 1) Fabricate interdigital electrodes as a growth substrate; in this embodiment, interdigital electrodes with a 100-μm pitch metal electrode are used as the growth substrate, the substrate material is PI, and the metal material is Au.

[0030] 2) Place Bi2Se3 powder as a growth source in a chemical vapor deposition device (the commonly used device model in the embodiment is BTF-1200C, Anhui Beike Co., Ltd., the maximum temperature is 1200 °C, the working temperature is 1100 °C, and the rated power is 3 KW); place the interdigital electrodes in the chemical vapor deposition device.

[0031] In the embodiment, the diameter of the quartz tube of the tube furnace is 100 mm; weigh 30 mg of Bi2Se3 powder in a quartz boat as the growth source, and at the same time place the substrate on a quartz plate with a width of 80 mm. Starting from the left edge of the quartz plate, place 1 substrate at each 1-cm horizontal position along the horizontal direction of the electrode, with a total of 10 columns. In order to prevent the material from covering the electrode and affecting the test results on each substrate, use a quartz sheet with a size of 0.7 cm × 1 cm × 0.1 cm to cover the electrode on the substrate. After placing the quartz boat in the marked central position in the upper quartz tube of the tube furnace, place the quartz plate at a distance of 29 cm, and the substrate is 30 - 39 cm away from the heating center (30, 31, 32, 33, 34, 35, 36, 37, 38, 39 cm)

[0032] 3) The BiSe thin film was grown on a flexible substrate by chemical vapor deposition to obtain a BiSe flexible infrared detector. In the embodiment, the mechanical pump was turned on to evacuate the inside of the quartz tube to a vacuum state. While the mechanical pump was kept on, the carrier gas Ar was introduced, and the gas flow rate was regulated to 500 sccm. After the first introduction of Ar for 30 s, the gas was turned off. After waiting for the inside to reach a vacuum, the gas was turned on again for 10 s. After repeating this twice, the gas was kept flowing, and the internal pressure was controlled to be about 360 Pa under this condition. The temperature and time during the growth process were set. The heating-up time was set to 60 min, and after heating to 700 °C, the temperature of 700 °C was maintained for growth for 30 min. Then, it was naturally cooled to room temperature. After turning off the heating switch, the gas cylinder valve was first closed. After pumping for 1 min, the device gas was turned off, and the sample was taken out. A BiSe detector based on interdigital electrodes was prepared.

[0033] Test:

[0034] The prepared BiSe detector was tested by SEM and EDS, and the results showed that the relative atomic percentage content ratio of Bi:Se was At% = 49.98:50.02, which could prove that the grown material was BiSe with an atomic ratio of 1:1. Figure 7 It was found that the crystal zone axis direction of the grown BiSe was

[100] , the observation direction was (010), and the atomic spacing was 0.4 nm, which was a layered crystal structure.

[0035] The BiSe flexible infrared detector obtained by growth was tested under a bias voltage of 0.1 V at a light power of 52 mW at 8 μm. During the test, a pulsed optical signal with a period of 10 s was used. The test results are as Figure 8 shown. Among them, the abscissa is time, and the ordinate is the test current of the device. As the optical signal makes a periodic switching action over time, the device current changes accordingly. The responsivity calculation formula is: change in current / (device area × optical power density). In this device, since the spot area is smaller than the device area and is the inscribed circle of a square device, the actual optical power measured is used for calculation. The spot is approximately a circle with a radius of 0.5 cm, and the final responsivity obtained is 9.988E-04 A / W.

Claims

1. A method for preparing a BiSe-based flexible detector, characterized in that: The following steps are involved: 1) manufacturing the interdigital electrode as a growth substrate; 2) placing Bi2Se3 powder as a growth source in a chemical vapor deposition device; placing an interdigitated electrode in a chemical vapor deposition device; 3) BiSe thin film is grown on a flexible substrate by chemical vapor deposition to obtain a BiSe flexible infrared detector.

2. The method for preparing a BiSe-based flexible detector according to claim 1, characterized in that: In step 1), polyimide (PI) is used as a flexible insulating substrate for the interdigital electrodes, and Au electrodes are fabricated on the flexible substrate to form the interdigital electrodes.

3. The method for preparing a BiSe-based flexible detector according to claim 1, characterized in that: In step 2), Bi2Se3 powder is placed in a tube furnace, and the substrate growth position is at the end of the air flow direction.

4. The method for preparing a BiSe-based flexible detector according to claim 1, characterized in that: In step 2), during deposition, the electrode contacts are protected.

5. The method for preparing a BiSe-based flexible detector according to claim 1, characterized in that: In step 3), after the inside of the quartz tube is evacuated, carrier gas Ar is introduced, the gas flow rate and the internal pressure are adjusted, and heating is performed until the reaction is completed. After cooling, the BiSe detector based on the interdigital electrode is taken out.

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