WO2013117018A1

WO2013117018A1 - P-type conductive sb doped sno2 thin film, tin oxide homogenous pn junction containing same, and methods for preparation thereof

Info

Publication number: WO2013117018A1
Application number: PCT/CN2012/071302
Authority: WO
Inventors: 赵修建; 倪佳苗; 耿硕麒; 刘启明
Original assignee: 武汉理工大学
Priority date: 2012-02-10
Filing date: 2012-02-20
Publication date: 2013-08-15
Also published as: CN102586748A

Abstract

Provided are a p-type conductive Sb doped SnO₂ thin film, a tin oxide homogenous pn junction containing same, and methods for preparation thereof. A method for preparing a p-type Sb doped SnO₂ thin film comprises using Sb doped SnO₂ ceramic target material and using a magnetron sputtering method to carry out the preparation on a single crystal Si or a quartz glass; and the tin oxide homogenous pn junction is obtained by sputtering and depositing a n-type Sb doped SnO₂ thin film onto the p-type Sb doped SnO₂ thin film. The p-type conductive Sb doped SnO₂ thin film has a stable electrical conductive performance, a high hole concentration, hole mobility and conductivity, having a hole concentration of up to an order of magnitude of 10²⁰cm^-3, a conductivity of up to 60S∙cm^-1 and at the same time a hole mobility of up to 2-30cm²∙V^-1∙s^-1, and a high transparency for visible light. The method for preparation thereof has simple processes, has good reproducibility, and is easy to use industrially. The prepared homogenous tin oxide-based transparent pn junction has the current-voltage profile characteristics of a semiconductor pn junction with a wide band gap.

Description

P-type conductive Sb-doped SnO2 film and tin oxide homogenous pn junction containing the same and preparation method thereof

Technical field

The invention belongs to the technical field of transparent conductive materials, in particular to a p-type conductive Sb-doped SnO ₂ film with high conductivity, high hole concentration, high mobility and high visible light transmittance and corresponding tin oxide homogenous pn Knot and its preparation method.

Background technique

Transparent conductive oxide (TCO) film and its corresponding transparent pn junction in the ultraviolet, violet blue light-emitting diode (LED), laser (LD), energy-saving white LED, gas sensor, solar cell, liquid crystal display, smart window, etc. The field has broad application prospects. Although various high-performance n-type TCO materials have been obtained so far, such as Sn-doped In ₂ O ₃ (ITO), Al-doped ZnO (AZO), etc., it is difficult due to self-compensation effects in oxide semiconductors. A high performance p-type TCO material is obtained by doping. Due to the large number of oxygen vacancies, metal interstitial atoms and other types of donor-type defects in the metal oxide material, the undoped oxide material is generally n-type, that is, the conduction band is electrically conductive. Due to the lack of good performance p-type TCO materials, high-performance transparent pn junctions are difficult to implement, and pn junctions are the basic components of most semiconductor transparent electronic devices, which seriously hinders the wide application of transparent semiconductor films in the semiconductor field. Therefore, how to realize p-type doping of high-performance TCO materials and prepare corresponding transparent pn junctions is the key to realize the wide application of TCO materials in the field of optoelectronics.

There are two main types of p-type transparent conductive oxide films reported at home and abroad, one is CuMO ₂ conductive film mainly composed of copper iron ore structure, and the other is p-type wide band gap oxidation doped by acceptor. Materials such as Li-doped p-type NiO and N-doped p-type ZnO thin films. The hole carrier concentration and p-type conductivity of these p-type TCO materials are respectively on the order of ~10 ¹⁷ cm ^-3 and below 1 S × cm ^-1 . Compared with the performance of the n-type TCO film, the carrier concentration and conductivity are both 2 to 3 orders of magnitude lower, and a wide band gap transparent pn junction with good performance cannot be realized. Therefore, it is more important to prepare a p-type conductive film having excellent performance.

Compared with ZnO, tin dioxide (SnO ₂ ) is a wide-bandgap semiconductor material with great development potential. The band gap is 3.5~4.0eV, and the larger exciton binding energy (SnO ₂ :130meV, ZnO:60meV) As a room temperature luminescent material, SnO ₂ has greater potential. Therefore, at present, p-type acceptor-doped SnO _{2 is} attracting attention, and the doping element of p-SnO ₂ is mainly concentrated in group I and III elements, such as Li, Al, In, and the like. Bagheri-Mohagheghi et al. (MM Bagheri-Mohagheghi, MS Saremi, J. Appl. Phys. 37 (2004) 1248 and MM Bagheri-Mohagheghi, MSSaremi, Semicond. Sci. Technol. 19 (2004) 764.) by spray pyrolysis Preparation of p-type Li-doped SnO ₂ film and Al-doped SnO ₂ film with a hole concentration of the order of ~10 ¹⁸ cm ^-3 ; Ji Zhenguo et al (Ji Zhenguo, He Zhenjie, a P-type conductive indium oxide film, patent application) No.: 03141558.X) A p-type In-doped SnO ₂ film was prepared by a sol-gel method, and its hole concentration was on the order of 10 ¹⁵ to 10 ¹⁶ cm ^-3 . The p-type TCO film prepared at present has a relatively low hole concentration, generally in the order of 10 ¹⁷ ~ 10 ¹⁸ cm ^-3 , and its resistivity is also relatively high, and there are problems such as poor repeatability and poor stability.

So far, there have been many reports on the preparation of p-type SnO ₂ thin films, and their research work mainly uses a sol-gel method and a spray pyrolysis method. When the film is deposited on a glass substrate by the sol-gel method, there are problems such as poor compactness and uniformity of the large-area film, and the thickness control thereof is difficult.

technical problem

The technical problem to be solved by the present invention is to provide a p-type conductive Sb-doped SnO ₂ film with excellent performance and stability and obtain a tin oxide homogenous pn junction for the above-mentioned prior art, and the obtained p-type conductive Sb-doped SnO _{2 The} film has stable electrical conductivity, high hole concentration, hole mobility and electrical conductivity, and has a hole concentration of up to 10 ²⁰ cm ^-3 and a conductivity of up to 60 S∙cm ^-1 , and the hole mobility can be as high as 2~ 30 cm ² ∙V ^-1 ∙s ^-1 , which has high transparency in visible light, and the preparation method has the advantages of simple process, good repeatability, easy industrialization, high practical value, and transparent preparation of homogeneous tin oxide base. The pn junction has a volt-ampere curve characteristic of a wide band gap semiconductor pn junction.

Technical solution

The technical solution adopted by the present invention to solve the above technical problems is: a method for preparing a p-type Sb-doped SnO ₂ film, comprising the following steps:

1) The SnO ₂ and Sb ₂ O ₃ powders are uniformly mixed, and after compression molding, sintering is performed to obtain a p-type Sb-doped SnO ₂ ceramic target;

2) The p-type Sb-doped SnO ₂ ceramic target obtained in the step 1) is made by a magnetron sputtering method using a single crystal Si piece or quartz glass as a substrate, and argon gas is used as a working gas, and the working gas pressure is 0.5 to 2.0. Pa, sputtering power 50~150W, sputter deposition time is 10~100 minutes, wherein: when using quartz glass as the substrate, the substrate temperature is 100-300 °C, and the film obtained by magnetron sputtering is deposited in argon Under the atmosphere, heat treatment at 550 ° C ~ 800 ° C for 1 ~ 6 hours, then naturally cooled, that is, p-type conductive Sb-doped SnO ₂ film; when using single crystal Si sheet as the substrate, the substrate temperature is controlled at 150 ° C ~ 300 °C, a p-type conductive Sb-doped SnO ₂ film is obtained.

According to the above scheme, the atomic ratio of Sb/(Sb+Sn) in the SnO ₂ and Sb ₂ O ₃ powder is 13 to 40:100.

According to the above scheme, the sintering temperature is 1000 ° C ~ 1250 ° C, and the sintering time is 3-7 hours.

A p-type Sb-doped SnO ₂ film characterized by a p-type Sb-doped SnO ₂ film prepared according to the above-described method for preparing a p-type Sb-doped SnO ₂ film.

A tin oxide homogenous pn junction characterized by comprising the above-mentioned p-type Sb-doped SnO ₂ film, and the p-type Sb-doped SnO ₂ film is also magnetron sputter deposited with an n-type Sb doping SnO ₂ film.

The preparation method of the tin oxide homogenous pn junction comprises the following steps:

1) The production method of the SnO ₂ film doped p-type prepared Sb Sb-doped p-type conductive SnO ₂ film;

2) SnO ₂ and Sb ₂ O ₅ powder are uniformly mixed, and after compression molding, sintering is performed to obtain an n-type Sb-doped SnO ₂ ceramic target;

3) using the n-type Sb-doped SnO ₂ ceramic target obtained in the step 2), and depositing a layer of n-type Sb doping on the p-type Sb-doped SnO ₂ film obtained in the step 1) by magnetron sputtering. The SnO ₂ film has a substrate temperature of 50 to 150 ° C and a mixed gas of argon and oxygen as a working gas. The total working pressure is 0.5 to 2.0 Pa, the oxygen partial pressure is 0.1 to 0.3 Pa, and the sputtering power is 50 to 150 W. The sputter deposition time is 10 to 100 minutes, that is, the tin oxide homogenous pn junction is obtained.

According to the above scheme, the atomic ratio of Sb/(Sb+Sn) in the SnO ₂ and Sb ₂ O ₅ powders is 2 to 12:100.

According to the above scheme, the sintering temperature in the step 2) is 1000 ° C to 1250 ° C, and the sintering time is 3 to 7 hours.

The present invention deposits a p-type SnO ₂ film on a substrate by a magnetron sputtering method. Magnetron sputtering is a relatively mature technology in film preparation. The deposited film has the advantages of high density, uniformity, thickness controllability, repeatability and stability, and is suitable for large-scale industrial production.

Through the above steps, a tin oxide homogenous pn junction can be prepared on a single crystal Si sheet and quartz glass, respectively. In order to facilitate the voltammetric curve test of the pn junction, the Ag electrode of the appropriate area was deposited on the n-type and p-type SnO ₂ films of the homogeneous pn junction of the tin oxide by magnetron sputtering using metal Ag as a target.

Incorporating trivalent europium (Sb) in tin dioxide to replace tetravalent tin (Sn) to produce conductive holes, obtaining a p-type conductive Sb-doped SnO ₂ film; and substituting pentavalent antimony (Sb) for tetravalent Tin (Sn), producing conductive electrons, obtaining an n-type conductive Sb-doped SnO ₂ film; finally preparing a homogenous pn junction of tin oxide. Due to the valence reaction of hydrazine, when the amount of incorporation is small, the ruthenium is mainly positive valence, and when the amount of ruthenium is high, most ruthenium is positive valence. It is found that p-type tin oxide can be obtained when the atomic ratio of Sb/(Sb+Sn) is 13~40:100, when the atomic ratio of Sb/(Sb+Sn) is 2~12:100. An n-type SnO ₂ film can be obtained.

Beneficial effect

The invention has the beneficial effects that the obtained p-type SnO ₂ transparent conductive film has high hole concentration, carrier mobility and electrical conductivity, and can reach carriers similar to the existing high-performance n-type TCO film. Concentration, carrier mobility and conductivity, enabling high-performance transparent pn junctions, such as light-emitting diodes (LEDs), lasers (LD), energy-saving white LEDs, gas sensors, solar cells in the ultraviolet and violet blue bands , liquid crystal display, smart window and other fields have broad application prospects. Moreover, the preparation method adopts a magnetron sputtering method with mature technology and easy control of process conditions, and is suitable for large-scale industrial production, and the prepared film has high compactness, uniformity, thickness controllability, performance repeatability and stability, etc. advantage. For example, a p-type film with a quartz glass substrate as a substrate has a hole concentration of 1.722×10 ²⁰ cm ^-3 , a hole mobility of 2.196 cm ² ∙V ^-1 ∙s ^-1 , and an electrical conductivity of up to 60.61 S·cm. ^-1 . When the single crystal Si substrate is used as the substrate, the hole carrier concentration can reach 1.638×10 ²⁰ cm ^-3 , the hole mobility reaches 8.33 cm ² ∙V ^-1 ∙s ^-1 , and the conductivity is up to 41.5 S. · cm ^-1 ; and can successfully prepare quartz glass substrate and single crystal Si substrate as the substrate of homogeneous tin oxide pn junction, with good wide band gap semiconductor pn junction volt-ampere characteristics.

DRAWINGS

1 is an ultraviolet-visible transmission spectrum of a p-type Sb-doped SnO ₂ film when a quartz glass substrate is used as a substrate, wherein the abscissa is the wavelength of light and the ordinate is the transmittance;

2 is an X-ray diffraction (XRD) pattern of a p-type Sb-doped SnO ₂ film on a quartz glass substrate;

Figure 3 is an X-ray photoelectron spectroscopy (XPS) spectrum of O1s and Sb ₃ d _3/2 in a p-type Sb-doped SnO ₂ film based on a quartz glass substrate. The small image embedded in the upper right is Sb ₃ a fit of the d _3/2 peak;

4 is an X-ray diffraction (XRD) pattern of a p-type Sb doped SnO ₂ film when a single crystal Si (100) substrate is used as a substrate;

Figure 5 is an X-ray photoelectron spectroscopy (XPS) spectrum of O1s and Sb ₃ d _3/2 in a p-type Sb-doped SnO ₂ film with a single crystal silicon substrate as the substrate. The above figure shows O1s and Sb ₃ d. _3/2 peak;

Figure 6 is a volt-ampere characteristic curve of a tin oxide homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) prepared on a quartz glass substrate, in which the abscissa is voltage and the ordinate is current. The embedded upper left panel shows the volt-ampere graph of a single p-type and n-type film after plating a pair of Ag electrodes on a single p-type and n-type Sb-doped SnO ₂ film, respectively;

Figure 7 is a UV-Vis transmission spectrum of a tin oxide homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) based on a quartz glass substrate. The abscissa is the wavelength of light, vertical The coordinates are the transmittance;

Figure 8 is a volt-ampere characteristic curve of a tin oxide homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) prepared on a single crystal Si (100) substrate, in which the abscissa is voltage, vertical The coordinates are current, and the upper left panel shows the volt-ampere curve of the single-layer p-type and n-type films after plating the Ag electrodes on the p-type and n-type SnO ₂ films, respectively.

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1

1) Weigh the purity of ≧99.9% of SnO ₂ and Sb ₂ O ₃ powder, wherein the atomic ratio of Sb/(Sb+Sn) is 33:100, and pour the above powder into a ball mill jar containing agate balls to add water. The ethanol was wet-milled, and the ball milling time was 5 hours, so that the powder was more uniformly mixed and refined to some extent. The ground material was then dried in a dry box at a temperature of 100 ° C for 10 hours. The dried raw material is ground in an agate grind, and then the raw material is press-formed by a mold. The formed embryo body is further subjected to cold isostatic pressing at 200 MPa, finally placed in a sintering furnace, heated to 1250 ° C at a rate of 3 ° C per minute, kept for 5 hours, and naturally cooled to obtain a p-type Sb-doped SnO ₂ ceramic target;

2) Using the p-type Sb-doped SnO ₂ ceramic target prepared in step 1), using magnetron sputtering method, using quartz glass as the substrate, the substrate temperature is 200 ° C, and working with high purity argon as working gas. The gas pressure was 1.0 Pa, the sputtering power was 100 W, and the sputtering deposition time was 45 minutes, and the film thickness was about 850 nm. Finally, the deposited film was placed in a heat treatment furnace, heat-treated at 650 ° C for 4 hours under an argon atmosphere, and then slowly cooled to room temperature to be taken out, thereby completing the preparation of the p-type conductive Sb-doped SnO ₂ film.

After testing, the p-type conductive Sb-doped SnO ₂ film has excellent electrical properties at room temperature: conductivity is 60.61 S·cm ^-1 , hole concentration is 1.722×10 ²⁰ cm ^-3 , Hall mobility is 2.196 cm ² ·V ^-1 ·s ^-1 . Moreover, there was no significant change in electrical properties after the film sample was placed for 5 months. The UV-Vis spectrum of the film, as shown in Figure 1, has a high transmittance in the visible range and an average transmittance of 85% or more. The X-ray diffraction (XRD) pattern of the film, as shown in Fig. 2, shows only the diffraction peak of SnO ₂ , the film is polycrystalline, and preferentially grows along the (110) plane, indicating the p-type produced by the method of the present invention. The Sb-doped SnO ₂ film has good crystallization properties. The O1s and Sb ₃ d _3/2 photoelectron spectra of the film are shown in Fig. 3. The peak of O1s binding energy is 530.2 eV, and the peak shape of Sb ₃ d _3/2 is independent and symmetrical. It can be fitted as a single peak and a peak position. At 539.5 eV, it can be seen from the comparison of the standard map that oxygen in the film exists in a negative divalent form and Sb in a positive trivalent form. In combination with the XRD pattern, the p-type Sb-doped SnO ₂ film prepared by the method of the invention has good crystallinity, and most of the Sb enters the substitution position of Sn with Sb ³⁺ , so the film exhibits good p-type conductivity.

Embodiments of the invention

Example 2

1) Weigh the purity of ≧99.9% of SnO ₂ and Sb ₂ O ₃ powder, wherein the atomic ratio of Sb/(Sb+Sn) is 18:100, and pour the above powder into a ball mill jar containing agate balls to add water. The ethanol was wet-milled, and the ball milling time was 5 hours, so that the powder was more uniformly mixed and refined to some extent. The ground material was then dried in a dry box at a temperature of 100 ° C for 10 hours. The dried raw material is ground in an agate grind, and then the raw material is press-formed by a mold. The formed embryo body is further subjected to 200 MPa cold isostatic pressing, and finally placed in a sintering furnace, and heated at a rate of 3 ° C per minute to 1250 ° C, kept for 5 hours, and naturally cooled to obtain a p-type Sb-doped SnO ₂ ceramic target. .

2) Using the Sb-doped SnO ₂ ceramic target prepared in step 1), using a magnetron sputtering method, using a single crystal Si (100) sheet as a substrate, a substrate temperature of 250 ° C, and working with high purity argon gas. The gas, the working pressure was 1.0 Pa, the sputtering power was 100 W, and the sputtering deposition time was 28 minutes, and the obtained film thickness was about 800 nm. After the deposition, the film does not need to be annealed, and after cooling in a vacuum chamber, the p-type conductive Sb-doped SnO ₂ film is obtained.

After testing, the p-type conductive Sb-doped SnO ₂ film has excellent electrical properties at room temperature: conductivity of 41.5 S·cm ^-1 , hole concentration of 1.638 × 10 ²⁰ cm ^-3 , Hall mobility of 8.33 cm ² ·V ^-1 ·s ^-1 . Moreover, there was no significant change in electrical properties after the film sample was placed for 5 months. The X-ray diffraction (XRD) pattern of the film, as shown in FIG. 4, except that the peak at 2θ ≈ 33.16° is derived from the single crystal silicon substrate, the other peaks are derived from the diffraction peak of SnO ₂ , and the film is a polycrystalline structure. And preferential growth along the (101) plane, indicating that the p-type Sb-doped SnO ₂ film produced by the method of the present invention has good crystallinity. The O1s and Sb ₃ d _3/2 photoelectron spectra of the film are shown in Fig. 5. The binding peak of O1s is 530.0 eV. According to the standard map, the oxygen in the film exists in the form of negative divalent. The figure below shows the fit of the Sb ₃ d _3/2 peak. The peak of the fitted peak is at 539.7 eV, corresponding to the positive trivalent Sb ³⁺ , and the peak with a binding energy of 541.2 eV (corresponding to Sb ⁵⁺ ), indicating the p-type Sb doping with the single crystal silicon substrate as the substrate. In the hetero-SnO ₂ film, Sb exists in the form of a positive trivalent Sb ³⁺ . In combination with the XRD pattern, the p-type Sb-doped SnO ₂ film prepared by the method of the invention has good crystallinity, and most of the Sb enters the substitution position of Sn in the form of Sb ³⁺ , so the film exhibits good p-type conductivity. performance.

Embodiments of the invention

Example 3

The p-type Sb-doped SnO ₂ film prepared on the quartz substrate obtained in Example 1 was used as a substrate, and the first p-type Sb-doped SnO ₂ film was further plated by RF magnetron sputtering. A second layer of n-type Sb doped SnO ₂ film. The specific method is as follows:

1) Preparation of n-type Sb-doped SnO ₂ ceramic target: SnO ₂ and Sb ₂ O ₅ powders with a purity of ≧99.9% were weighed, wherein the atomic ratio of Sb/(Sb+Sn) was 11:100, and the above powder was used. The ball mill is uniformly mixed, press-formed, and then sintered at a temperature of 1250 ° C for 5 h to obtain an n-type Sb-doped SnO ₂ ceramic target;

2) The n-type Sb-doped SnO ₂ ceramic target prepared by the step 1) is lining the quartz glass plated with the p-type Sb-doped SnO ₂ film obtained in the first embodiment by a magnetron sputtering method. the end of the p-type deposition of Sb-doped SnO ₂ and then n-type thin film of Sb-doped SnO ₂ film, a substrate temperature of 100 deg.] C, a mixed gas of oxygen and high purity argon gas as a working gas, the working gas pressure 1.0 total Pa, the partial pressure of oxygen was 0.2 Pa, the sputtering power was 100 W, and the sputtering deposition time was 30 minutes, and the thickness of the n-type film was about 800 nm.

Through the above steps, the preparation of a homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) on quartz glass was completed. In order to test the voltammetric curve test of the homogeneous tin oxide pn junction, the n- and p-type Sb-doped SnO ₂ films on the homogenous pn junction were finally deposited on the metal Ag target by magnetron sputtering. Ag electrode.

The volt-ampere characteristic curve of the above homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) prepared on a quartz substrate is shown in Fig. 6. The top left panel shows the volt-ampere curve of the single-layer p-type and n-type films after the Ag electrode is plated on the p-type and n-type SnO ₂ films, respectively. It is a straight line, meaning that the Ag electrode has good ohmic contact with the p, n-type Sb-doped SnO ₂ film, respectively. The embedded lower right panel shows the compositional structure of the homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb). An Ag electrode was plated on the n- and p-type Sb-doped SnO ₂ films, respectively, in order to test the volt-ampere curve of the pn junction. It can be obtained from the volt-ampere curve of Figure 6. This is a typical pn junction volt-ampere curve with a threshold voltage of ~2.5V and a certain leakage current in the reverse direction. It was also confirmed that the trivalent Sb-doped SnO ₂ film deposited on the quartz substrate was p-type conductive.

The ultraviolet visible spectrum (UV-Vis) of the tin oxide homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) obtained on the quartz glass substrate obtained above is as shown in FIG. The tin homogenous pn junction has a transmittance of 60-85% in the visible light range, and is colorless and transparent by visual observation.

Embodiments of the invention

Example 4

The p-type Sb-doped SnO ₂ film prepared on the single crystal Si (100) substrate obtained in Example 2 was used as a substrate, and the first layer of p-type Sb was doped with SnO ₂ by RF magnetron sputtering. A second layer of n-type Sb-doped SnO ₂ film is further plated on the film. The specific method is as follows:

1) Preparation of n-type Sb-doped SnO ₂ ceramic target: Weigh the purity of ≧99.9% of SnO ₂ and Sb ₂ O ₅ powder, wherein the atomic ratio of Sb/(Sb+Sn) is 6:100, the above powder The ball mill was uniformly mixed, press-formed, and then sintered at a temperature of 1,250 ° C for 5 hours to obtain an n-type Sb-doped SnO ₂ ceramic target.

2) The n-type Sb-doped SnO ₂ ceramic target prepared by the step 1) is re-deposited on the p-type Sb-doped SnO ₂ film prepared on the single crystal Si (100) substrate by magnetron sputtering. A layer of n-type Sb-doped SnO ₂ film with a substrate temperature of 100 ° C, a mixed gas of high purity argon and oxygen as working gas, working pressure of 0.8 Pa, oxygen partial pressure of 0.2 Pa, sputtering power of 100 W, sputtering At a time of 28 minutes, the film thickness obtained was about 800 nm.

Through the above steps, preparation of a homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) on single crystal Si (100) was completed. In order to test the voltammetric curve test of the homogeneous tin oxide pn junction, finally, an Ag electrode of an appropriate size was separately deposited from the metal Ag target by magnetron sputtering on the obtained n- and p-type SnO ₂ thin films.

The volt-ampere characteristic curve of the above homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb) was tested as shown in FIG. The top left panel shows the volt-ampere curve of the single-layer p-type and n-type films after the Ag electrode is plated on the p-type and n-type Sb-doped SnO ₂ films, respectively. The An-curve is a straight line, meaning that the Ag electrode has good ohmic contact with the p- and n-type Sb-doped SnO ₂ films, respectively. The embedded lower right panel shows the compositional structure of the homogenous pn junction (p-SnO ₂ :Sb/n-SnO ₂ :Sb). The n- and p-type Sb-doped SnO ₂ films are respectively plated with an Ag electrode to facilitate testing the volt-ampere curve of the pn junction, as shown in Fig. 8, which is a non-linear volt-ampere curve showing this homogenous pn The junction has good rectification characteristics, the threshold voltage is ~5V, the reverse breakdown voltage is greater than 15V, and the leakage current is small. At the same time, it was once again proved that the trivalent Sb-doped SnO ₂ film deposited on the single crystal Si substrate was p-type conductive.

Claims

1. A method for preparing a p-type Sb-doped SnO ₂ film, comprising the steps of:

The method for preparing a p-type Sb-doped SnO ₂ film according to claim 1, wherein an atomic ratio of Sb/(Sb+Sn) in said SnO ₂ and Sb ₂ O ₃ powder is 13 to 40 :100.

The method for preparing a p-type Sb-doped SnO ₂ film according to claim 1 or 2, wherein the sintering temperature in the step 1) is from 1000 ° C to 1250 ° C, and the sintering time is from 3 to 7 hours.

A p-type Sb-doped SnO ₂ film characterized by the p-type Sb-doped SnO ₂ film prepared by the method for preparing a p-type Sb-doped SnO ₂ film according to any one of claims 1 to 3.

A tin oxide homogenous pn junction characterized by comprising the p-type Sb-doped SnO ₂ film according to claim 4, wherein said p-type Sb-doped SnO ₂ film is further magnetron sputter deposited thereon. There is a layer of n-type Sb doped SnO ₂ film.

6. The method for preparing a tin oxide homogenous pn junction according to claim 5, comprising the steps of:

1) according to claim 1 Sb-doped p-type SnO ₂ thin film preparation prepared Sb-doped p-type conductive SnO ₂ film as claimed in claim;

The method for preparing a tin oxide homogenous pn junction according to claim 6, wherein the atomic ratio of Sb/(Sb+Sn) in the SnO ₂ and Sb ₂ O ₅ powders in the step 2) is 2~ 12:100.

The method for preparing a tin oxide homogenous pn junction according to claim 6 or 7, wherein the sintering temperature in the step 2) is from 1000 ° C to 1250 ° C, and the sintering time is from 3 to 7 hours.