Selenium-doped indium sulfide thin film and preparation method and application thereof

Abstract

The invention discloses a selenium-doped indium sulfide film and a preparation method and application thereof, and belongs to the technical field of preparation of two-dimensional semiconductor materials. The preparation method of the selenium-doped indium sulfide thin film comprises the following steps that sulfur serves as a doping source, In2Se3 and In2S3 serve as growth sources, deposition is conducted on a substrate through a chemical vapor deposition method, and the selenium-doped indium sulfide thin film is obtained. The selenium-doped indium sulfide thin film (Se-In2S3 thin film) prepared by the method is moderate in size, uniform in thickness and regular in shape, has good photoelectric response performance, is a good semiconductor material, and is suitable for optical communication devices, thermal imaging devices and the like from a visible light wave band to a near-infrared wave band.

Description

Technical Field

[0001] The present invention relates to the technical field of two-dimensional semiconductor material preparation, and particularly to a selenium-doped indium sulfide thin film, a preparation method thereof, and an application thereof. Background Art

[0002] Two-dimensional materials refer to new materials with atomic-level thickness, usually monolayer or few-layer, and infinitely extending in two dimensions in the plane direction. Their structural feature is that atoms within the layer are bonded by strong chemical bonds, while layers are bonded by weak van der Waals forces. By controlling the number of layers, properties can be adjusted. For example, monolayer MoS2 is a direct-bandgap semiconductor, and it becomes an indirect-bandgap when it is multilayered. Vertically stacking with other materials can form heterojunctions to achieve multifunctional integration. However, it is difficult to prepare high-quality single-crystal materials on a large scale, and it is difficult to ensure the control of the number of layers and uniformity, which will generate defects such as vacancies and grain boundaries. The existence of defects affects the recombination process of photo-generated carriers, and further affects the optoelectronic properties of two-dimensional semiconductor materials in different wavelength bands, restricting the application of these materials in semiconductor devices. And how to achieve the large-scale preparation of two-dimensional materials and broaden the response of two-dimensional materials in different wavelength bands has become a technical problem to be solved by those skilled in the art. Summary of the Invention

[0003] The purpose of the present invention is to provide a selenium-doped indium sulfide thin film, a preparation method thereof, and an application thereof to solve the problems existing in the above-mentioned prior art.

[0004] To achieve the above purpose, the present invention provides the following solutions:

[0005] One of the technical solutions of the present invention: A preparation method of a selenium-doped indium sulfide thin film, comprising the following steps: using sulfur as a doping source, using In2Se3 and In2S3 as growth sources, and depositing on a substrate by chemical vapor deposition to obtain the selenium-doped indium sulfide thin film.

[0006] Preferably, the preparation method of the selenium-doped indium sulfide thin film comprises the following steps:

[0007] Placing the doping source at a position 29.5 cm from the center of the first heating zone and close to the second heating zone, placing the growth source at the center of the second heating zone, placing the substrate above the growth source, evacuating and then introducing an inert gas, heating the first heating zone with a heating source, then raising the temperature of the first heating zone to the deposition temperature, and then quickly moving the heating source to the second heating zone to raise the temperature of the second heating zone to the deposition temperature, keeping warm and then removing the heating source, and cooling to obtain the selenium-doped indium sulfide thin film;

[0008] Wherein, the first heating zone and the second heating zone are horizontally arranged;

[0009] The inert gas first passes through the first heating zone and then through the second heating zone;

[0010] The heating source covers the first heating zone or the second heating zone.

[0011] Preferably, heating the first heating zone using the heating source includes: heating the temperature of the first heating zone to 790 - 820 °C at a heating rate of 25 °C / min.

[0012] Preferably, raising the temperature of the first heating zone to the deposition temperature includes: raising the temperature of the first heating zone to 845 - 910 °C at a heating rate of 9 - 11 °C / min.

[0013] Preferably, the flow rate of the inert gas when heating the first heating zone using the heating source is 150 - 200 sccm;

[0014] The flow rate of the inert gas during heat preservation is 70 - 80 sccm;

[0015] The flow rate of the inert gas during cooling is 150 - 200 sccm.

[0016] Preferably, the heat preservation time is 3 min 30 s - 5 min 30 s.

[0017] Preferably, the mass ratio of In2Se3 to In2S3 is 9:1 - 1:8.

[0018] Preferably, the horizontal distance between the doping source and the growth source is 28 - 32 cm;

[0019] The maximum vertical distance between the substrate and the growth source is 5 - 20 mm.

[0020] Two-dimensional indium sulfide (In2S3) has a relatively wide bandgap (about 2.0 - 2.4 eV), mainly absorbs ultraviolet-visible light, but has weak absorption ability for near-infrared light, and the wide bandgap will cause large carrier thermal relaxation losses, and photo-generated electron-hole pairs are easily recombined, unable to generate a response in the infrared band, which limits its application in near-infrared band optical communication devices (such as solar cells).

[0021] Indium selenide (InSe) has a relatively narrow bandgap (about 1.3 - 1.5 eV), suitable for infrared light absorption, but has low efficiency in high-energy photon (such as ultraviolet light) scenarios.

[0022] The van der Waals layered structure of two-dimensional indium sulfide and indium selenide results in low mechanical strength, easy peeling or fracture, affecting device stability. The Schottky barriers between them and the metal electrodes are relatively high, resulting in large contact resistance, especially significant in thin-film devices.

[0023] In the present invention, selenium (Se) is incorporated into the In2S3 lattice by chemical vapor deposition to form a Se-In2S3 thin film, which can combine the advantages of the two materials and regulate the performance: there is a band gap difference between In2Se3 and In2S3, and continuous band gap regulation can be achieved by adjusting the Se / S ratio, covering the visible light to near-infrared spectrum, and meeting the requirements of optoelectronic devices in the visible light band to near-infrared band. Moreover, doping selenium (Se) in In2S3 can improve the charge transport performance of photo-generated carriers in In2S3, reduce the density of deep-level defect states, enhance the photocurrent response, and expand the light absorption range, making it suitable for near-infrared photodetectors.

[0024] The second technical solution of the present invention: a selenium-doped indium sulfide thin film prepared by the above preparation method.

[0025] The third technical solution of the present invention: an application of the above selenium-doped indium sulfide thin film in semiconductor devices.

[0026] Preferably, the semiconductor devices include two-dimensional semiconductor photodetectors, optical communication devices in the near-infrared band, and thermal imaging devices.

[0027] The present invention discloses the following technical effects:

[0028] (1) The selenium-doped indium sulfide thin film (Se-In2S3 thin film) prepared by the present invention has a moderate size (the maximum size can reach 713.63 μm 2 ), uniform thickness, and regular shape (showing a regular triangular distribution in a large area), has good optoelectronic response performance, is a good semiconductor material, and is suitable for optical communication devices, thermal imaging devices, etc. in the visible light band to near-infrared band.

[0029] (2) By adjusting the ratio of In2Se3 and In2S3, the doping amount of selenium (Se) in Se-In2S3 can be changed, and the light wavelength can be broadened.

[0030] (3) The preparation method of the present invention is simple to operate, the reaction equipment used has a high safety factor, the reaction conditions are easy to control, and the influence coefficient of external conditions during the preparation process is small; in addition, the items involved in the preparation process are non-toxic or have low toxicity. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0032] Figure 1It is a physical picture of the placement method of the substrate on the quartz boat in the embodiment;

[0033] Figure 2 It is a schematic structural diagram of the experimental device adopted in the embodiment;

[0034] Figure 3 It is an optical micrograph of the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) prepared in Example 1;

[0035] Figure 4 It is a Raman diagram of the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) prepared in Example 1;

[0036] Figure 5 It is an optical micrograph of the electrode built with the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) prepared in Example 1;

[0037] Figure 6 It is the light response curves of the thin film (1S9Se-845℃) prepared in Example 1 at 405nm, 532nm, 635nm, and 808nm;

[0038] Figure 7 It is the light response curves of the thin film (2S1Se-880℃) prepared in Example 2 at 405nm, 532nm, 635nm, and 808nm;

[0039] Figure 8 It is the light response curves of the thin film (4S1Se-880℃) prepared in Example 3 at 405nm, 532nm, 635nm, and 808nm;

[0040] Figure 9 It is the light response curves of the thin film (6S1Se-880℃) prepared in Example 4 at 405nm, 532nm, 635nm, and 808nm;

[0041] Figure 10 It is the light response curves of the thin film (8S1Se-880℃) prepared in Example 5 at 405nm, 532nm, 635nm, and 808nm;

[0042] Figure 11 It is the light response curves of the thin film (2S1Se-890℃) prepared in Example 6 at 405nm, 532nm, 635nm, and 808nm;

[0043] Figure 12 It is the light response curves of the thin film (4S1Se-890℃) prepared in Example 7 at 405nm, 532nm, 635nm, and 808nm;

[0044] Figure 13 Photoresponse curves of the thin film prepared in Example 8 (6S1Se - 890 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0045] Figure 14 Photoresponse curves of the thin film prepared in Example 9 (8S1Se - 890 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0046] Figure 15 Photoresponse curves of the thin film prepared in Example 10 (2S1Se - 900 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0047] Figure 16 Photoresponse curves of the thin film prepared in Example 11 (4S1Se - 900 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0048] Figure 17 Photoresponse curves of the thin film prepared in Example 12 (6S1Se - 900 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0049] Figure 18 Photoresponse curves of the thin film prepared in Example 13 (8S1Se - 900 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0050] Figure 19 Photoresponse curves of the thin film prepared in Comparative Example 1 (In2S3 - 910 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0051] Figure 20 Photoresponse curves of the thin film prepared in Comparative Example 2 (In2Se3 - 845 °C) at 405 nm, 532 nm, 635 nm, and 808 nm;

[0052] Figure 21 PL curves of the thin film prepared in Comparative Example 1 (In2S3 - 910 °C), the thin film prepared in Example 10 (2S1Se - 900 °C), the thin film prepared in Example 11 (4S1Se - 900 °C), the thin film prepared in Example 12 (6S1Se - 900 °C), and the thin film prepared in Example 13 (8S1Se - 900 °C);

[0053] Figure 22PL curves of the thin films prepared in Example 6 (2S1Se - 890 °C), Example 7 (4S1Se - 890 °C), Example 8 (6S1Se - 890 °C), and Example 9 (8S1Se - 890 °C);

[0054] Figure 23 PL curves of the thin films prepared in Example 1 (1S9Se - 845 °C), Example 2 (2S1Se - 880 °C), Example 3 (4S1Se - 880 °C), Example 4 (6S1Se - 880 °C), Example 5 (8S1Se - 880 °C), and the thin film prepared in Comparative Example 2 (In2Se3 - 845 °C). Detailed implementation manners

[0055] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0056] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0057] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0058] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are only exemplary.

[0059] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open - ended terms, meaning including but not limited to.

[0060] It should be noted that the aspects not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0061] In the following examples, "parts" all refer to "parts by mass".

[0062] The first aspect of the present invention: provides a method for preparing a selenium-doped indium sulfide thin film, comprising the following steps: using sulfur as a doping source, using In2Se3 and In2S3 as growth sources, and depositing on a substrate by chemical vapor deposition to obtain the selenium-doped indium sulfide thin film.

[0063] Further, the method for preparing the selenium-doped indium sulfide thin film comprises the following steps:

[0064] (1) Cut the substrate to obtain a substrate with a fresh surface.

[0065] (2) Place the growth source on a quartz boat, place the fresh surface of the substrate downward and obliquely in the quartz boat, and place the doping source on another quartz boat.

[0066] (3) Place the quartz boat with the doping source at a position 29.5 cm from the center of the first heating zone of the slide rail furnace and close to the second heating zone, and place the quartz boat with the growth source and the substrate at the center of the second heating zone of the slide rail furnace.

[0067] Among them, the first heating zone and the second heating zone are horizontally arranged.

[0068] The inert gas first passes through the first heating zone and then through the second heating zone.

[0069] (4) Close the intake valve and the exhaust valve of the slide rail furnace to ensure the airtightness of the furnace. Open the air pump, evacuate the air pressure in the slide rail furnace to -1 Pa, and then open the intake valve to introduce inert gas to 0 Pa; repeat the above operation more than 3 times to ensure that the air in the slide rail furnace (inside the quartz tube in the slide rail furnace) is fully exhausted.

[0070] (5) Close the air pump, open the intake valve and the exhaust valve, introduce inert gas, turn on the heating source of the slide rail furnace, heat the first heating zone (heat the temperature of the first heating zone to 790 - 820 °C at a heating rate of 25 °C / min), control the flow rate of the inert gas to be 150 - 200 sccm during the heating process; then continue to heat up, raise the temperature of the first heating zone to the deposition temperature, and at this time quickly move the heating source to the second heating zone, raise the temperature of the second heating zone to the deposition temperature and keep it warm, the flow rate of the inert gas during the warming process is 70 - 80 sccm, then move the heating source out of the second heating zone, and adjust the flow rate of the inert gas to 150 - 200 sccm. When the temperature in the furnace cools to below 100 °C, turn off the gas flow to obtain a two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film).

[0071] Among them, the heating source covers the first heating zone or the second heating zone.

[0072] Preferably, in step (1), the substrate is a fluorophlogopite sheet with a specification of 15 mm × 15 mm × 0.2 mm; the substrate with one side being a fresh surface is obtained by cutting a fluorophlogopite sheet with a specification of 15 mm × 15 mm × 0.2 mm into a fluorophlogopite sheet with a specification of 15 mm × 15 mm × 0.1 mm.

[0073] Preferably, in step (2), the growth source is In2Se3 and In2S3 with a mass ratio of 9:1 to 1:8, and the doping source is sulfur powder.

[0074] Preferably, in step (2), the maximum vertical distance between the substrate and the growth source is 5 - 20 mm.

[0075] Preferably, in step (3), the horizontal distance between the doping source and the growth source is 28 - 32 cm, and more preferably 29.5 cm.

[0076] Preferably, in steps (4) and (5), the inert gas is argon.

[0077] Preferably, in step (5), raising the temperature of the second heating zone to the deposition temperature and then holding the temperature includes: raising the temperature at a heating rate of 9 - 11 °C / min to 845 - 910 °C and holding the temperature for 3 min 30 s - 5 min 30 s.

[0078] Preferably, the flow rate of the inert gas during the heating and cooling processes is 180 sccm, and the flow rate of the inert gas during the holding process is 70 sccm.

[0079] Preferably, cotton is stuffed at both ends of the rail furnace to prevent the sample sources (doping source and growth source) in the quartz tube of the rail furnace from being blown into the ventilation pipeline and blocking the ventilation pipeline.

[0080] In the second aspect of the present invention, there is provided a selenium-doped indium sulfide thin film prepared by the above preparation method.

[0081] In the third aspect of the present invention, there is provided an application of the above selenium-doped indium sulfide thin film in semiconductor devices.

[0082] Preferably, the semiconductor devices include two-dimensional semiconductor photodetectors, optical communication devices in the near-infrared band, and thermal imaging devices.

[0083] Example 1

[0084] A preparation method of a selenium-doped indium sulfide thin film:

[0085] (1) Weigh precisely a mixture of In2Se3 and In2S3 with a mass ratio of 9:1 on an electronic balance to obtain the growth source.

[0086] Take a piece of fluorophlogopite mica sheet (with dimensions of 15 mm × 15 mm × 0.2 mm), cut it, and obtain a substrate with a fresh surface (with dimensions of 15 mm × 15 mm × 0.1 mm).

[0087] (2) Place 3 mg of the growth source on a quartz boat, cover the quartz boat with the fresh surface of the substrate facing down obliquely (the maximum vertical distance between the substrate and the growth source is 5 mm), make one side of the substrate contact the bottom of the quartz boat, and the other side rest on the upper part of the quartz boat. Weigh 0.1 g of the doping source (sulfur powder) and place it on another quartz boat.

[0088] The physical diagram of the placement method of the substrate on the quartz boat is shown in Figure 1 .

[0089] (3) Place the quartz boat containing the doping source at a position 29.5 cm from the center of the first heating zone of the quartz tube of the sliding rail furnace and close to the second heating zone. Place the quartz boat containing the growth source and the substrate on the center of the second heating zone of the quartz tube of the sliding rail furnace ( Figure 2 ), and make a mark; among them, the horizontal distance between the doping source and the growth source is 29.5 cm; in addition, place two pieces of cotton at both ends of the sliding rail furnace to prevent the sample source in the quartz tube of the sliding rail furnace from being blown into the ventilation pipeline and causing blockage.

[0090] Among them, the first heating zone and the second heating zone are horizontally arranged. The first heating zone is located on the left side of the quartz tube of the sliding rail furnace, the second heating zone is located on the right side of the quartz tube of the sliding rail furnace, the air inlet is located on the left side of the first heating zone, and the air outlet is located on the right side of the second heating zone.

[0091] (4) Close the intake valve and outlet valve of the sliding rail furnace to ensure the airtightness inside the tube. Turn on the vacuum pump to evacuate the air. After pumping the air pressure inside the tube below -1 Pa, keep it for 50 s; turn off the vacuum pump, turn on the intake valve to introduce argon, and close the intake valve to stop the ventilation after the air pressure inside the tube reaches atmospheric pressure; repeat the above operation more than 3 times to ensure that the impurity gases inside the tube are fully exhausted.

[0092] (5) Open the intake valve and outlet valve of the sliding rail furnace, and introduce argon with a flow rate of 180 sccm into the furnace tube of the sliding rail furnace; move the heating source of the sliding rail furnace to the first heating zone;

[0093] Among them, the heating source covers the first heating zone.

[0094] (6) Turn on the heating source of the sliding rail furnace and heat the temperature of the first heating zone to 800 °C at a heating rate of 25 °C / min. During the heating process, the flow rate of argon gas introduced is maintained at 180 sccm; subsequently, heat the temperature of the first heating zone to the deposition temperature (845 °C) at a heating rate of 9 °C / min. When the temperature is stable, quickly move the sliding rail furnace horizontally to the second heating zone (i.e., the marked area) to heat the temperature of the second heating zone to the deposition temperature (845 °C), keep it warm for 5 min, and maintain the flow rate of argon gas introduced at 80 sccm during the heat preservation process. Deposit a two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) on the fluorophlogopite sheet by chemical vapor deposition method.

[0095] Among them, the heating source covers the second heating zone.

[0096] (7) After the growth is completed, move the heating source of the sliding rail furnace to the first heating zone and adjust the flow rate of argon gas introduced to 180 sccm; subsequently, wait until the temperature inside the sliding rail furnace drops below 100 °C and then close the gas flow.

[0097] (8) After the chemical vapor deposition is completed, open the cavity and take out the fluorophlogopite sheet deposited with the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film); transfer the sample on the fluorophlogopite sheet to Si / SiO2 with polystyrene, place it under an optical microscope for observation, and it can be found that its shape is regular, triangular, and the thickness is uniform, as Figure 3 shown.

[0098] The Raman diagram of the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) prepared in this example is shown in Figure 4 .

[0099] From Figure 4 it can be seen that the Raman peaks of Se element and S element in the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) prepared in this example are consistent with the ideal peaks.

[0100] Adopt this example to prepare the required electrode pattern on the Si / SiO2 substrate containing the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) through maskless lithography and development, then evaporate metal gold on the obtained electrode pattern mask to form an electrode, remove the photoresist with acetone, and perform vacuum high-temperature annealing to obtain a two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) device, that is, a two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) photodetector. The optical micrograph of the two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) photodetector is shown in Figure 5 .

[0101] Example 2

[0102] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:2;

[0103] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 880 °C.

[0104] The obtained two-dimensional selenium-doped indium sulfide film (Se-In2S3 film) has a regular shape and a uniform thickness.

[0105] Example 3

[0106] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:4;

[0107] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 880 °C.

[0108] The obtained two-dimensional selenium-doped indium sulfide film (Se-In2S3 film) has a regular shape and a uniform thickness.

[0109] Example 4

[0110] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:6;

[0111] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 880 °C.

[0112] The obtained two-dimensional selenium-doped indium sulfide film (Se-In2S3 film) has a regular shape and a uniform thickness.

[0113] Example 5

[0114] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:8;

[0115] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 880 °C.

[0116] The obtained two-dimensional selenium-doped indium sulfide film (Se-In2S3 film) has a regular shape and a uniform thickness.

[0117] Example 6

[0118] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:2;

[0119] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 890 °C.

[0120] The obtained two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) has regular shape and uniform thickness.

[0121] Example 7

[0122] Same as Example 1, the only difference is that in step (1), the mass ratio of In2Se3 to In2S3 is 1:4;

[0123] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 890 °C.

[0124] The obtained two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) has regular shape and uniform thickness.

[0125] Example 8

[0126] Same as Example 1, the only difference is that in step (1), the mass ratio of In2Se3 to In2S3 is 1:6;

[0127] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 890 °C.

[0128] The obtained two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) has regular shape and uniform thickness.

[0129] Example 9

[0130] Same as Example 1, the only difference is that in step (1), the mass ratio of In2Se3 to In2S3 is 1:8;

[0131] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 890 °C.

[0132] The obtained two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) has regular shape and uniform thickness.

[0133] Example 10

[0134] Same as Example 1, the only difference is that in step (1), the mass ratio of In2Se3 to In2S3 is 1:2;

[0135] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 900 °C.

[0136] The obtained two-dimensional selenium-doped indium sulfide thin film (Se-In2S3 thin film) has regular shape and uniform thickness.

[0137] Example 11

[0138] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:4;

[0139] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 900 °C.

[0140] The obtained two-dimensional selenium-doped indium sulfide film (Se-In2S3 film) has a regular shape and a uniform thickness.

[0141] Example 12

[0142] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:6;

[0143] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 900 °C.

[0144] The obtained two-dimensional selenium-doped indium sulfide film (Se-In2S3 film) has a regular shape and a uniform thickness.

[0145] Example 13

[0146] Same as Example 1, except that in step (1), the mass ratio of In2Se3 to In2S3 is 1:8;

[0147] In step (6), the heating rate to the deposition temperature is 10 °C / min, and the deposition temperature is 900 °C.

[0148] The obtained two-dimensional selenium-doped indium sulfide film (Se-In2S3 film) has a regular shape and a uniform thickness.

[0149] Comparative Example 1

[0150] Same as Example 1, except that in step (1), In2Se3 and In2S3 are replaced with In2S3.

[0151] In step (6), the heating rate to the deposition temperature is 11 °C / min, and the deposition temperature is 910 °C.

[0152] Comparative Example 2

[0153] Same as Example 1, except that in step (1), In2Se3 and In2S3 are replaced with In2Se3.

[0154] In step (6), the heating rate to the deposition temperature is 9 °C / min, and the deposition temperature is 845 °C.

[0155] Effect Example 1

[0156] Figures 6 - 20Photoresponse curves of the thin films prepared in Examples 1 to 13 and Comparative Examples 1 to 2 at 405 nm, 532 nm, 635 nm, and 808 nm, respectively.

[0157] It can be seen from Figures 6 - 20 that continuous regulation of the bandgap can be achieved by adjusting the Se / S ratio, covering the visible to near-infrared spectrum and meeting the requirements of optoelectronic devices in the visible to near-infrared wavelength range.

[0158] Effect Example 2

[0159] The PL curves of the thin films prepared in Comparative Example 1 (In2S3 - 910 °C), Example 10 (2S1Se - 900 °C), Example 11 (4S1Se - 900 °C), Example 12 (6S1Se - 900 °C), and Example 13 (8S1Se - 900 °C) are shown in Figure 21 ;

[0160] The PL curves of the thin films prepared in Example 6 (2S1Se - 890 °C), Example 7 (4S1Se - 890 °C), Example 8 (6S1Se - 890 °C), and Example 9 (8S1Se - 890 °C) are shown in Figure 22 ;

[0161] The PL curves of the thin films prepared in Example 1 (1S9Se - 845 °C), Example 2 (2S1Se - 880 °C), Example 3 (4S1Se - 880 °C), Example 4 (6S1Se - 880 °C), Example 5 (8S1Se - 880 °C), and Comparative Example 2 (In2Se3 - 845 °C) are shown in Figure 23 .

[0162] It can be seen from Figures 21 - 23 that as the content of Se in Se-In2S3 increases continuously, the PL curve of Se-In2S3 undergoes a red shift. Compared with elemental In2Se3 and In2S3, continuous regulation of the bandgap can be achieved by adjusting the Se / S ratio, covering the visible to near-infrared spectrum.

[0163] The above-described embodiments are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a selenium-doped indium sulfide thin film, characterized in that: The following steps are involved: Sulfur is used as a doping source, In2Se3 and In2S3 are used as growth sources, and deposition is performed on a substrate by chemical vapor deposition to obtain the selenium-doped indium sulfide film.

2. The preparation method according to claim 1, characterized in that: The method for preparing the selenium-doped indium sulfide film comprises the following steps: The doping source is placed at a position 29.5 cm away from the center of the first heating zone and close to the second heating zone, the growth source is placed at the center of the second heating zone, and the substrate is placed above the growth source. After evacuation, an inert gas is introduced, and the first heating zone is heated by the heating source. Then, the temperature of the first heating zone is increased to the deposition temperature, and then the heating source is quickly moved to the second heating zone to increase the temperature of the second heating zone to the deposition temperature. After heat preservation, the heating source is removed, and the film is cooled to obtain the selenium-doped indium sulfide film. Wherein, the first heating zone and the second heating zone are arranged horizontally; The inert gas first passes through the first heating zone and then passes through the second heating zone; The heating source covers the first heating zone or the second heating zone.

3. The preparation method according to claim 2, characterized in that: The heating of the first heating zone by using a heating source includes: heating the temperature of the first heating zone to 790-820° C. at a heating rate of 25° C. / min.

4. The preparation method according to claim 2, characterized in that: The step of increasing the temperature of the first heating zone to a deposition temperature includes increasing the temperature of the first heating zone to 845-910° C. at a heating rate of 9-11° C. / min.

5. The preparation method according to claim 2, characterized in that: The inert gas flow rate when the first heating zone is heated by the heating source is 150-200 sccm; And / or, the inert gas flow rate during the heat preservation is 70-80 sccm; And / or, the inert gas flow rate during the cooling is 150-200 sccm.

6. The preparation method according to claim 2, characterized in that: The insulation time is 3min30s~5min30s.

7. The preparation method according to claim 2, characterized in that: The mass ratio of In2Se3 to In2S3 is 9:1~1:

8.

8. The preparation method according to claim 2, characterized in that: The horizontal distance between the doping source and the growth source is 28-32 cm; And / or, the maximum vertical distance between the substrate and the growth source is 5 to 20 mm.

9. A selenium-doped indium sulfide thin film prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the selenium-doped indium sulfide film according to claim 9 in a semiconductor device.

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