CN112376113B

CN112376113B - Antimony selenide crystal, preparation method and application thereof

Info

Publication number: CN112376113B
Application number: CN202011167874.8A
Authority: CN
Inventors: 刘新胜; 刘永军; 刘景玲; 李二浩; 庄玉君; 程轲; 杜祖亮
Original assignee: Henan University
Current assignee: Henan University
Priority date: 2020-10-28
Filing date: 2020-10-28
Publication date: 2022-02-11
Anticipated expiration: 2040-10-28
Also published as: CN112376113A

Abstract

The invention discloses an antimony selenide crystal, a preparation method and application thereof. The invention prepares the antimony selenide amorphous prefabricated layer by a magnetron sputtering method, a selenium source and the prefabricated layer are respectively arranged at two ends of a double-temperature-zone rapid annealing furnace during selenization, the carrier gas flow, the selenization air pressure and the temperature rise programs at the two ends of the double-temperature-zone rapid annealing furnace are adjusted, the selenization air pressure is far lower than the saturated vapor pressure of elemental selenium at the selenium source temperature, the selenium flux during selenization is improved, and a large-grain antimony selenide crystal growing along the (hk 0) orientation is obtained. The antimony selenide crystal prepared by the method grows along the (hk 0) orientation and has larger crystal grains, thereby effectively avoiding the influence of crystal boundaries and suspension bonds on the carrier transmission, improving the carrier transmission rate in a specific direction, effectively improving the photoelectrochemistry hydrogen production efficiency and having wide application in the field of photoelectrochemistry.

Description

Antimony selenide crystal, preparation method and application thereof

Technical Field

The invention belongs to the field of photoelectric material preparation, and particularly relates to an antimony selenide crystal, and a preparation method and application thereof.

Background

Antimony selenide is a binary compound semiconductor, the constituent elements of antimony and selenium are low in toxicity and rich in reserves, the forbidden band width of antimony selenide is proper (-1.1 eV), and the antimony selenide has excellent light absorption performance (the light absorption coefficient is more than 10)⁵cm^-1) In recent years, attention has been paid to the field of optoelectronics. The antimony selenide crystal has a unique quasi-one-dimensional band-shaped crystal structure, in-band atoms are connected through covalent bonds, and the bands are stacked together through Van der Waals force, so that the transmission rate of carriers in the bands is far greater than that between the bands, and therefore, the antimony selenide material has strong anisotropy in optical and electrical properties.

Antimony selenide crystal can form more composite centers at dangling bonds and crystal boundaries due to the crystal structure of the antimony selenide crystal, and the antimony selenide crystal can be used as a trap to capture free carriers, so that the carriers have low mobility (electron transmission rate mu is approximately equal to 15 cm) in different orientations and different crystal grains² V^-1 s ^-1) This limits the use of antimony selenide in the photovoltaic field. At present, the preparation methods of high-quality antimony selenide crystal films include a rapid thermal evaporation method (RTE), a near space sublimation method (CSS), a vapor transport deposition method (VTD), an in-situ heating magnetron sputtering method, a magnetron sputtering post-selenization method and the like, and in order to improve the carrier mobility of the antimony selenide crystal film, growth conditions are controlled to enable the film to be preferentially oriented along (001), crystal grains penetrating through the whole film are obtained, the transmission rate of carriers is improved, and more excellent photoelectric properties are obtained. However, the preparation method of the antimony selenide crystal film still has certain limitationsThe crystal grain size is limited to 1-2 μm, orientation disorder, and (001) orientation specific gravity (peak intensity specific gravity) is low. The research on finding an antimony selenide crystal film with larger grains and more consistent orientation can separate the film to prepare structures such as an antimony selenide single crystal, an antimony selenide layer, an antimony selenide rod and the like, can exert the characteristics of the antimony selenide crystal, and expand the application of antimony selenide materials in the photoelectric field is always a target pursued by researchers in the field.

Disclosure of Invention

The preparation method can prepare the large-grain antimony selenide crystal oriented along the (hk 0), and effectively avoids the defects of mixed orientation and small grains generated in the preparation process of the existing antimony selenide crystal film, thereby improving the photoelectrochemistry hydrogen production efficiency.

Based on the purpose, the invention adopts the following technical scheme:

a preparation method of antimony selenide crystals comprises the following steps:

(1) preparing an amorphous antimony selenide prefabricated layer on a substrate to be prepared into a film by adopting a radio frequency magnetron sputtering process, wherein the thickness of the amorphous antimony selenide prefabricated layer is 500-2000 nm, and the selenium molar content in the amorphous prefabricated layer is 0-45%;

(2) placing the obtained amorphous antimony selenide prefabricated layer at one end of a dual-temperature-zone rapid annealing furnace, placing a selenium source at the other end, and setting a corresponding temperature-raising program, wherein the temperature-raising program at the end of the prefabricated layer is set as follows: the temperature rise rate is 0.1-10 ℃/s, the constant temperature is 350-480 ℃, the time for maintaining the temperature is 300-1300 s, the selenium source is selenium powder or selenium particles, and the temperature rise program of the selenium source end is set as follows: the heating rate is 0.1-12 ℃/s, the constant temperature is 400-700 ℃, and the time for maintaining the temperature is 300-1300 s; and (3) the carrier gas is argon, the flow of the carrier gas is set to be 10 sccm-150 sccm, the pressure of the antimony selenide is set to be 0.1 Torr-20 Torr, after the procedure is completely finished, when the temperature is reduced to 200 ℃, the furnace cover of the rapid annealing furnace is opened, the annealing furnace is continuously cooled, when the temperature of a thermocouple at the end of the antimony selenide film is lower than 100 ℃, the vacuum is broken, and the sample is taken out, so that the antimony selenide film with large grains grown along the (hk 0) orientation is obtained.

Further, the substrate to be made into the film is SLG/Mo, SLG or SLG/FTO.

Further, the temperature raising program of the precast layer end is specifically set as follows: c1: 30, T1: 50, C2: 300, T2: 300, C3: 300, T3: 40, C4: 350-520, T4: 600-900, C5: 350-520, T5: the program was terminated, C denotes temperature in deg.C, T denotes time in seconds.

Further, the temperature range of the selenium source end is set as follows: c1: 30, T1: 50, C2: 400, T2: 300, C3: 400, T3: 40, C4: 400-700, T4: 600-900, C5: 400-700, T5: the program was terminated, C denotes temperature in deg.C, T denotes time in seconds.

Further, the sputtering power for preparing the amorphous antimony selenide prefabricated layer in the step (1) is 80w, and the sputtering time is 50-120 min.

The antimony selenide crystal prepared by the preparation method.

The antimony selenide crystal is applied to photoelectrochemistry hydrogen production.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the amorphous antimony selenide prefabricated layer is prepared on the substrate to be prepared into the film by adopting a radio frequency magnetron sputtering process, and in the selenizing process, the high-flux selenium is reacted with the amorphous antimony selenide prefabricated layer by adjusting the selenium source temperature, the selenizing air pressure and the carrier gas flow, so that the large-grain antimony selenide film with preferred orientation along (hk 0) is prepared, and the (hk 0) orientation has higher specific gravity in the whole body. By simply separating the selenium source from the antimony selenide prefabricated layer and controlling the key factor of selenization, the pressure of the selenization is far lower than the saturated vapor pressure at the selenization temperature, the reaction of high-flux selenium and the antimony selenide prefabricated layer is realized, the antimony selenide film with high (hk 0) orientation and large crystal grains is obtained, the dangling bonds and the crystal boundary in the antimony selenide crystal are effectively reduced, the transmission rate of a carrier in a specific orientation is obviously increased, and the efficiency of the photoelectrochemistry hydrogen production of the antimony selenide is improved; meanwhile, the application range of the antimony selenide crystal in the field of photoelectrochemistry is expanded.

Drawings

FIG. 1 is an X-ray diffraction pattern of an amorphous antimony selenide film pre-fabricated layer sputtered on the surface of a Mo/SLG substrate in example 1 of the present invention;

FIG. 2 is an X-ray diffraction pattern of a large-grained antimony selenide crystal prepared in example 1 of the present invention;

FIG. 3 is a cross-sectional scanning electron microscope image of a large-grained antimony selenide crystal prepared in example 1 of the present invention;

FIG. 4 is an X-ray diffraction pattern of a large-grained antimony selenide crystal prepared in example 2 of the invention;

FIG. 5 is a cross-sectional scanning electron microscope image of a large-grained antimony selenide crystal prepared in example 2 of the present invention;

FIG. 6 is an X-ray diffraction pattern of a large-grained antimony selenide crystal prepared in example 3 of the invention;

FIG. 7 is a cross-sectional scanning electron microscope image of a large-grained antimony selenide crystal prepared in example 3 of the present invention;

FIG. 8 is an X-ray diffraction pattern of a large-grained antimony selenide crystal prepared in example 4 of the invention;

FIG. 9 is a cross-sectional scanning electron microscope image of a large-grained antimony selenide crystal prepared in example 4 of the present invention;

FIG. 10 is an X-ray diffraction pattern of an antimony selenide crystal prepared according to the present invention in comparative example 1 at a selenization pressure of 10 torr;

FIG. 11 is a cross-sectional scanning electron microscope image of antimony selenide crystals prepared at a pressure of 10torr for selenization in comparative example 1 of the present invention;

FIG. 12 is a linear voltammetry scan of a photoelectrochemical hydrogen production performance test of an antimony selenide crystal prepared by the method of the present invention;

FIG. 13 is a graph of the saturation vapor pressure of elemental selenium at different temperatures. The saturated vapor pressure of the selenium source increases along with the rise of the temperature, and when the selenizing air pressure is lower than the saturated vapor pressure at the selenizing temperature, the selenium source is in a boiling state, so that high-flux selenium can be provided.

Detailed Description

The method of the present invention will be described in detail below with reference to specific examples and the accompanying drawings. The magnetron sputtering instrument model adopted in the experiment is a high-vacuum single-target magnetron sputtering system manufactured by Shenyang scientific instrument development center, Inc. The model of the double-temperature-zone rapid annealing furnace is OTF-1200X-4-RTF-SL manufactured by the combined fertilizer crystal.

Preparation of antimony selenide crystal

Example 1:

(1) a soda-lime glass (SLG, 2cm × 2 cm) substrate was cleaned with acetone, isopropyl alcohol, ethanol, and high-purity water, and metallic molybdenum having a thickness of 1000nm was prepared on the SLG substrate as a back electrode using a direct-current magnetron sputtering process.

(2) An amorphous antimony selenide prefabricated layer with the thickness of 1000nm is prepared on a Mo/SLG substrate by using a radio frequency magnetron sputtering process, the sputtering power is 80W, the sputtering time is 100min, the X-ray diffraction pattern of the amorphous antimony selenide thin film prefabricated layer is shown in figure 1, as can be seen from figure 1, only one peak of a Mo electrode does not contain crystalline antimony selenide, and the molar ratio of Sb to Se in the amorphous antimony selenide prefabricated layer is =2: 3.

(3) Respectively placing the amorphous antimony selenide prefabricated layer and 2g of selenium particles at two ends of a dual-temperature-zone rapid annealing furnace, wherein the temperature range of the amorphous antimony selenide thin film end is set as follows: c1: 30, T1: 50, C2: 300, T2: 300, C3: 300, T3: 40, C4: 400, T4: 900, C5: 400, T5: -121; the temperature range of the selenium source end is set as follows: c1: 30, T1: 50, C2: 400, T2: 300, C3: 400, T3: 40, C4: 480, T4: 900, C5: 480, T5: -121. (where C denotes temperature in degrees Celsius (. degree. C.), T denotes time in seconds(s), -121 denotes an end temperature password). The carrier gas flow was set at 100 sccm. The selenization pressure was set at 2.0 torr. And after the procedure is completely finished and the temperature is reduced to below 200 ℃, opening the furnace cover of the rapid annealing furnace to continuously reduce the temperature, breaking the vacuum when the temperature of the thermocouple at the thin film end of the antimony selenide is below 100 ℃, and taking out a sample, wherein a figure 2 is an X-ray diffraction spectrum of the finally prepared large-grain antimony selenide crystal. As can be seen from fig. 2, the crystal is a pure antimony selenide crystal, contains no other secondary phase, and is preferentially oriented along the (hk 0) crystal plane, fig. 3 is a cross-sectional electron scanning microscope image of the large-grain antimony selenide crystal prepared in the present example, and as can be seen from fig. 3, the crystal is a large grain having a thickness of about 5 μm and a length of more than 30 μm.

Example 2:

(1) cleaning a soda-lime glass (SLG, 2cm multiplied by 2 cm) substrate by using acetone, isopropanol, ethanol and high-purity water, preparing an amorphous antimony selenide prefabricated layer with the thickness of 1200nm on the SLG substrate by using a radio frequency magnetron sputtering process, wherein the sputtering power is 80W, the sputtering time is 120min, and the Sb: Se molar ratio in the amorphous antimony selenide prefabricated layer is =2: 3.

(2) Respectively placing the amorphous antimony selenide prefabricated layer and 2g of selenium particles at two ends of a dual-temperature-zone rapid annealing furnace, wherein the temperature range of the amorphous antimony selenide thin film end is set as follows: c1: 30, T1: 50, C2: 300, T2: 300, C3: 300, T3: 40, C4: 400, T4: 900, C5: 400, T5: -121; the temperature range of the selenium source end is set as follows: c1: 30, T1: 50, C2: 400, T2: 300, C3: 400, T3: 40, C4: 480, T4: 900, C5: 480, T5: -121. (where C denotes temperature in degrees Celsius (. degree. C.), T denotes time in seconds(s), -121 denotes an end temperature password). The carrier gas flow was set at 100 sccm. The selenization pressure was set at 5.0 torr. And after the procedure is completely finished and the temperature is reduced to below 200 ℃, opening the furnace cover of the rapid annealing furnace to continuously reduce the temperature, breaking the vacuum when the temperature of the thermocouple at the end of the antimony selenide film is below 100 ℃, and taking out the sample.

Fig. 4 is an X-ray diffraction pattern of the large-grain antimony selenide crystal prepared in this example. As can be seen from FIG. 4, under these conditions, antimony selenide crystals preferentially oriented along (hk 0) and containing no other secondary phases can be prepared.

Fig. 5 is a cross-sectional scanning electron microscope image of the large-grained antimony selenide crystals prepared in the present example. As can be seen from FIG. 5, the large-grained antimony selenide crystals having a thickness of about 3 μm and a length exceeding 30 μm.

Example 3:

(1) and cleaning a soda-lime glass (SLG, 2cm multiplied by 2 cm) substrate by using acetone, isopropanol, ethanol and high-purity water, and preparing metal molybdenum with the thickness of 1000nm on the SLG substrate as a back electrode by using a direct-current magnetron sputtering process.

(2) Preparing an amorphous antimony selenide prefabricated layer with the thickness of 1000nm on the Mo/SLG substrate by using a radio frequency magnetron sputtering process, wherein the sputtering power is 80W, the sputtering time is 100min, and the molar ratio of Sb to Se in the amorphous antimony selenide prefabricated layer is =2: 3.

(3) Respectively placing the amorphous antimony selenide prefabricated layer and 2g of selenium grains at two ends of a dual-temperature-zone rapid annealing furnace, wherein the temperature range of the amorphous antimony selenide thin film end is set as: c1: 30, T1: 50, C2: 300, T2: 300, C3: 300, T3: 40, C4: 400, T4: 900, C5: 400, T5: -121; the temperature range of the selenium source end is set as follows: c1: 30, T1: 50, C2: 400, T2: 300, C3: 400, T3: 40, C4: 520, T4: 900, C5: 520, T5: -121. (where C denotes temperature in degrees Celsius (. degree. C.), T denotes time in seconds(s), -121 denotes an end temperature password). The carrier gas flow was set at 100 sccm. The selenization pressure was set at 5.0 torr. And after the procedure is completely finished and the temperature is reduced to below 200 ℃, opening the furnace cover of the rapid annealing furnace to continuously reduce the temperature, breaking the vacuum when the temperature of the thermocouple at the end of the antimony selenide film is below 100 ℃, and taking out the sample.

Fig. 6 is an X-ray diffraction pattern of the large-grain antimony selenide crystal prepared in this example. As can be seen from fig. 6, this condition enables the preparation of antimony selenide crystals oriented along (hk 0) without other secondary phases.

Fig. 7 is a cross-sectional electron scanning microscope image of the large-grain antimony selenide crystal prepared in this example. As can be seen from FIG. 7, antimony selenide crystals having a thickness of about 3 μm and a length greater than 30 μm.

Example 4:

(2) Preparing an amorphous antimony selenide prefabricated layer with the thickness of 800nm on the Mo/SLG substrate by using a radio frequency magnetron sputtering process, wherein the sputtering power is 80W, the sputtering time is 100min, and the molar ratio of Sb to Se in the amorphous antimony selenide prefabricated layer is =2: 3.

(3) Respectively placing the amorphous antimony selenide prefabricated layer and 2g of selenium grains at two ends of a dual-temperature-zone rapid annealing furnace, wherein the temperature range of the amorphous antimony selenide thin film end is set as: c1: 30, T1: 50, C2: 300, T2: 300, C3: 300, T3: 40, C4: 400, T4: 600, C5: 400, T5: -121; the temperature range of the selenium source end is set as follows: c1: 30, T1: 50, C2: 400, T2: 300, C3: 400, T3: 40, C4: 690, T4: 600, C5: 690, T5: -121. (where C denotes temperature in degrees Celsius (. degree. C.), T denotes time in seconds(s), -121 denotes an end temperature password). The carrier gas flow was set at 100 sccm. The selenization pressure was set at 5.0 torr. And after the procedure is completely finished and the temperature is reduced to below 200 ℃, opening the furnace cover of the rapid annealing furnace to continuously reduce the temperature, breaking the vacuum when the temperature of the thermocouple at the end of the antimony selenide film is below 100 ℃, and taking out the sample.

Fig. 8 is an X-ray diffraction pattern of the large-grain antimony selenide crystal prepared in this example. As can be seen from fig. 8, this condition enables the preparation of antimony selenide crystals oriented along (hk 0) without other secondary phases.

Fig. 9 is a cross-sectional electron scanning microscope image of the large-grained antimony selenide crystals prepared in this example. As can be seen from FIG. 9, the antimony selenide cylindrical crystal has a thickness of about 3 μm and a length of more than 30 μm.

Comparative example 1:

the key condition of the antimony selenide crystal prepared by the invention is that the selenizing pressure is controlled to be far lower than the saturated vapor pressure of a selenium simple substance at the selenium source temperature; therefore, there is a match between the selenization temperature and the selenization pressure. Under the condition of constant selenium source temperature, the large-grain antimony selenide growing along the (hk 0) orientation cannot be obtained by increasing the selenization pressure. In this comparative example, a gas pressure of 10torr is exemplified. The specific preparation method is basically the same as that in example 3, except that:

in the step (3), the temperature-raising programs and the carrier gas flow rates at the two ends of the dual-temperature-zone rapid annealing furnace are the same, and only the selenizing air pressure is set to be 10 Torr. As shown in fig. 10 and 11, XRD characterization and SEM morphology observation of the obtained thin film did not result in large-grain antimony selenide with preferred orientation along (hk 0).

Application of antimony selenide film in photoelectrochemistry hydrogen production

The photoelectrochemical hydrogen production performance test was performed on the antimony selenide crystal prepared in example 3. And respectively depositing a CdS buffer layer and platinum nanoparticles on the surface of the prepared antimony selenide crystal, wherein the thickness of the antimony selenide film is 1100nm, the thickness of the cadmium sulfide buffer layer is 60nm, and the thickness of the platinum nanoparticles is not more than 10 nm. The prepared device is placed in sulfuric acid electrolyte with pH =1 under the condition of standard sunlight irradiation (AM 1.5) for photoelectrochemistry hydrogen production performance test, wherein the photocathode is a platinum electrode. As a result, as shown in FIG. 12, the optical current density of the device at 0V was 7mA/cm^-1The antimony selenide crystal prepared by the method has better (hk 0) orientation, is beneficial to directional transmission of current carriers, and improves the performance of the antimony selenide photoelectrochemistry hydrogen production to a certain extent.

Although the present invention has been described in terms of preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the present invention, which is intended to be covered by the claims.

Claims

1. A preparation method of antimony selenide crystals is characterized by comprising the following steps:

(1) preparing an amorphous antimony selenide prefabricated layer on a substrate to be prepared into a film by adopting a radio frequency magnetron sputtering process, wherein the thickness of the amorphous antimony selenide prefabricated layer is 500-2000 nm, and the molar ratio of Sb to Se in the amorphous antimony selenide prefabricated layer is =2: 3; the substrate to be prepared into the membrane is SLG/Mo, SLG or SLG/FTO; the sputtering power is 80w and the sputtering time is 50-120 min when the amorphous antimony selenide prefabricated layer is prepared;

(2) placing the obtained amorphous antimony selenide prefabricated layer at one end of a dual-temperature-zone rapid annealing furnace, placing a selenium source at the other end, and setting a corresponding temperature-raising program, wherein the selenium source is selenium powder or selenium particles, and the temperature-raising program at the end of the prefabricated layer is specifically set as follows: c1: 30, T1: 50, C2: 300, T2: 300, C3: 300, T3: 40, C4: 400, T4: 600-900, C5: 400, T5: the program is terminated, C denotes temperature in deg.C, T denotes time in seconds;

the temperature range of the selenium source end is set as follows: c1: 30, T1: 50, C2: 400, T2: 300, C3: 400, T3: 40, C4: 480-: 600-900, C5: 480-: the program is terminated, C denotes temperature in deg.C, T denotes time in seconds; and (3) taking argon as carrier gas, setting the flow of the carrier gas to be 100sccm, setting the pressure of the selenide to be 2 Torr-5 Torr, opening a furnace cover of the rapid annealing furnace to continuously cool the furnace when the temperature is reduced to be below 200 ℃ after the procedure is completely finished, breaking vacuum when the temperature of a thermocouple at the end of the antimony selenide film is below 100 ℃, and taking out a sample.

2. Antimony selenide crystals prepared by the preparation method of claim 1.

3. The use of antimony selenide crystals as claimed in claim 2 in the photoelectrochemical production of hydrogen.