A preparation method of cuprous oxide - cuprous phosphide heterojunction

Abstract

The present invention discloses a preparation method of a cuprous oxide - cuprous phosphide heterojunction. First, a cuprous phosphide thin film is generated in the present invention. After that, a zinc oxide thin film is deposited on the surface of the cuprous phosphide, and then heat treatment is carried out to obtain p-type cuprous oxide. Secondly, the template method is used to deposit a zinc oxide thin film on the surface of the cuprous phosphide by magnetron sputtering. The zinc oxide thin film has an interdigital pattern. After heat treatment, the part with zinc oxide deposited on the surface is transformed into p-type cuprous oxide, forming an in-plane heterojunction of p-type cuprous oxide and p-type cuprous phosphide. Gold electrodes are deposited on the cuprous oxide and cuprous phosphide regions by thermal evaporation to prepare a heterojunction device. The heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide prepared by the present invention has low cost, good repeatability and good memristive performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation, and particularly relates to a method for preparing a cuprous oxide - cuprous phosphide heterojunction. Background Art

[0002] Most inorganic non - metallic semiconductor materials exhibit n - type conductivity, such as zinc oxide, titanium dioxide, indium - doped tin oxide, etc. Relatively speaking, p - type semiconductor materials are relatively few. Cuprous oxide is different from most metal oxides and usually exhibits p - type conductivity because theoretical analysis shows that the existence or introduction of intrinsic defects in cuprous oxide will not form n - type cuprous phosphide. Cuprous oxide exhibits good optoelectronic and fluorescence properties. With the understanding and development of memristors, the application research of cuprous oxide in the field of memristors is also in progress. Compared with n - type semiconductor materials, the research on memristors based on p - type semiconductor materials is relatively less. The different conduction types may affect the memristive performance of the device. In this patent, a homotypic p - type material heterojunction is constructed to obtain a memristor. Summary of the Invention

[0003] Aiming at the deficiencies of existing research, the present invention first proposes a method for preparing a p - type cuprous oxide - p - type cuprous phosphide heterojunction.

[0004] A method for preparing a cuprous oxide - cuprous phosphide heterojunction according to the present invention is as follows: After copper is phosphated, a cuprous phosphide thin film is formed. Then, a zinc oxide thin film is deposited on the surface of the cuprous phosphide, and then heat treatment is carried out to obtain p - type cuprous oxide. Secondly, the template method is used to deposit a zinc oxide thin film on the surface of the cuprous phosphide by magnetron sputtering. The zinc oxide thin film is in an interdigital pattern. After heat treatment, the part with zinc oxide deposited on the surface is transformed into p - type cuprous oxide, forming an in - plane heterojunction of p - type cuprous oxide and p - type cuprous phosphide. Gold electrodes are deposited on the cuprous oxide and cuprous phosphide regions by thermal evaporation to prepare a heterojunction device.

[0005] Step (1). Prepare a cuprous phosphide thin film;

[0006] A mask plate is placed on the surface of the cuprous phosphide thin film, and a zinc oxide thin film is deposited by magnetron sputtering. The zinc oxide thin film is in the shape of interdigital electrodes; the vacuum degree of the magnetron sputtering equipment is 0.1 - 1.0 Pa, the oxygen flow rate is 1 - 5 sccm, the argon flow rate is 20 - 50 sccm, the sputtering voltage is 300 - 450 V, the current is 30 - 60 mA, the sputtering time is 20 - 40 min, and the target is a metal zinc target; the thickness of the prepared zinc oxide thin film is 50 - 200 nm;

[0007] Step (3). The product of step (3) is placed into the quartz tube of a tube furnace, and an inert gas argon is filled. The quartz tube is heated with a heating rate of 20 °C / min until it reaches 760 - 850 °C and is held for 60 - 120 min. Then, the quartz tube is naturally cooled to room temperature to obtain a heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide.

[0008] Preferably, the preparation of the cuprous phosphide thin film specifically includes the following steps:

[0009] Step (1). Sodium hypophosphite is placed into a corundum boat, and then a copper foil with a thickness of 250 - 1000 microns is covered on the surface of the corundum boat.

[0010] Step (2). The corundum boat is placed into a corundum tube. After vacuum pumping, argon at 1 atmospheric pressure is filled, and then both ends of the corundum tube are sealed.

[0011] Step (3). The corundum tube is heated to 280 - 300 °C in a tube furnace with a heating rate of 10 °C / min. After the temperature reaches 280 - 300 °C, it is held for 30 - 60 min. Then, it is naturally cooled to room temperature. The corundum tube is vacuum pumped to remove the residual gas inside the tube, and then the product, the cuprous phosphide thin film, is taken out.

[0012] Preferably, the copper foil is replaced with a copper thin film grown on the surface of alumina or silica.

[0013] Preferably, the area of the copper foil is 1 - 5 square centimeters.

[0014] Preferably, the thickness of the copper foil is 600 microns.

[0015] The advantages of the present invention are as follows: The cuprous phosphide thin film is obtained by the copper phosphidation method; the zinc oxide thin film is locally deposited on the surface of the cuprous phosphide by the magnetron sputtering method. The combination between zinc oxide and cuprous phosphide is tight, and the composition and crystal structure of the cuprous phosphide will not be changed. In the part where the zinc oxide is locally deposited on the cuprous phosphide thin film, at high temperature, through atomic diffusion, chemical reaction, and high-temperature volatilization of zinc and phosphorus elements, a p-type cuprous oxide region is formed, and the p-type cuprous oxide region and the adjacent cuprous phosphide region form an in-plane heterojunction. The heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide prepared by the present invention has low cost, good repeatability, and good memristive performance. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of the product of the present invention. Detailed Embodiments

[0017] Example 1: Step (1). Preparation of the cuprous phosphide thin film; specifically includes the following steps:

[0018] Step ①. Put sodium hypophosphite into a corundum boat, and then cover the surface of the corundum boat with a copper foil having an area of 1 square centimeter and a thickness of 250 micrometers;

[0019] Step ②. Put the corundum boat into a corundum tube. After evacuating, fill it with argon at 1 atmospheric pressure, and then seal both ends of the corundum tube;

[0020] Step ③. Heat the corundum tube to 280 °C in a tube furnace at a heating rate of 10 °C / min; after the temperature rises to 280 °C, keep it warm for 30 min; then cool it naturally to room temperature. Evacuate the corundum tube to remove the residual gas inside the tube, and then take out the product cuprous phosphide thin film.

[0021] Step (2). Place a mask plate on the surface of the cuprous phosphide thin film, and deposit a zinc oxide thin film by magnetron sputtering. The zinc oxide thin film is in the shape of interdigital electrodes; the vacuum degree of the magnetron sputtering equipment is 0.1 Pa, the oxygen flow rate is 2 sccm, the argon flow rate is 20 sccm, the sputtering voltage is 300 V, the current is 30 mA, the sputtering time is 20 min, and the target is a metallic zinc target; the thickness of the prepared zinc oxide thin film is 50 nm;

[0022] Step (3). Put the product of Step (2) into a quartz tube of a tube furnace, fill it with the inert gas argon, heat the quartz tube at a heating rate of 20 °C / min, raise the temperature to 760 °C, and keep it warm for 60 min. Then, cool the quartz tube naturally to room temperature to obtain a heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide;

[0023] Step (4). Deposit gold electrodes on the cuprous oxide and cuprous phosphide regions by thermal evaporation to prepare a heterojunction device, as Figure 1 shown.

[0024] Example 2:

[0025] Step (1). Prepare a cuprous phosphide thin film; specifically including the following steps:

[0026] Step ①. Put sodium hypophosphite into a corundum boat, and then cover the surface of the corundum boat with a copper foil having an area of 3 square centimeters and a thickness of 600 micrometers;

[0027] Step ②. Put the corundum boat into a corundum tube. After evacuating, fill it with argon at 1 atmospheric pressure, and then seal both ends of the corundum tube;

[0028] Step ③. Heat the corundum tube to 290 °C in a tube furnace at a heating rate of 10 °C / min; after the temperature rises to 290 °C, keep it warm for 40 min; then cool it naturally to room temperature. Evacuate the corundum tube to remove the residual gas inside the tube, and then take out the product cuprous phosphide thin film.

[0029] Step (2). Place a mask on the surface of the cuprous phosphide thin film, and deposit a zinc oxide thin film by magnetron sputtering. The zinc oxide thin film is in the shape of interdigital electrodes; the vacuum degree of the magnetron sputtering equipment is 0.5 Pa, the oxygen flow rate is 3 sccm, the argon flow rate is 30 sccm, the sputtering voltage is 400 V, the current is 40 mA, the sputtering time is 30 min, and the target is a metallic zinc target; the thickness of the prepared zinc oxide thin film is 100 nm;

[0030] Step (3). Put the product of step (3) into the quartz tube of the tube furnace, fill it with the inert gas argon, heat the quartz tube, the heating rate of the quartz tube is 20 °C / min, raise the temperature to 790 °C, and keep it warm for 80 min, and then the quartz tube is naturally cooled to room temperature to obtain a heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide.

[0031] Example 3:

[0032] Step (1). Prepare a cuprous phosphide thin film; specifically including the following steps:

[0033] Step ①. Put sodium hypophosphite into the corundum boat, and then cover the surface of the corundum boat with a copper foil with an area of 5 square centimeters and a thickness of 1000 microns;

[0034] Step ②. Put the corundum boat into the corundum tube, evacuate it, fill it with argon at 1 atmospheric pressure, and then seal both ends of the corundum tube;

[0035] Step ③. Heat the corundum tube to 300 °C through the tube furnace, and the heating rate is 10 °C / min; after the temperature rises to 300 °C, keep it warm for 60 min; then naturally cool it to room temperature, evacuate the corundum tube to remove the residual gas in the tube, and then take out the product, the cuprous phosphide thin film.

[0036] Step (2). Place a mask on the surface of the cuprous phosphide thin film, and deposit a zinc oxide thin film by magnetron sputtering. The zinc oxide thin film is in the shape of interdigital electrodes; the vacuum degree of the magnetron sputtering equipment is 1.0 Pa, the oxygen flow rate is 5 sccm, the argon flow rate is 50 sccm, the sputtering voltage is 450 V, the current is 60 mA, the sputtering time is 40 min, and the target is a metallic zinc target; the thickness of the prepared zinc oxide thin film is 200 nm;

[0037] Step (3). Put the product of step (3) into the quartz tube of the tube furnace, fill it with the inert gas argon, heat the quartz tube, the heating rate of the quartz tube is 20 °C / min, raise the temperature to 850 °C, and keep it warm for 120 min, and then the quartz tube is naturally cooled to room temperature to obtain a heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide.

[0038] Example 4:

[0039] Step (1). Prepare a cuprous phosphide thin film; specifically including the following steps:

[0040] Step ①. Put sodium hypophosphite into a corundum boat, and then cover the surface of the corundum boat with a copper foil having an area of 3 square centimeters and a thickness of 500 micrometers; the copper foil is a copper thin film on the surface of silicon oxide.

[0041] Step ②. Put the corundum boat into a corundum tube, evacuate it, then fill it with argon at 1 atmospheric pressure, and then seal both ends of the corundum tube.

[0042] Step ③. Heat the corundum tube to 290 °C in a tube furnace at a heating rate of 10 °C / min; after the temperature rises to 290 °C, keep it warm for 50 min; then cool it naturally to room temperature, evacuate the corundum tube to remove the residual gas inside the tube, and then take out the product cuprous phosphide thin film.

[0043] Step (2). Place a mask plate on the surface of the cuprous phosphide thin film, and deposit a zinc oxide thin film by magnetron sputtering. The zinc oxide thin film is in the shape of interdigital electrodes; the vacuum degree of the magnetron sputtering equipment is 0.8 Pa, the oxygen flow rate is 3 sccm, the argon flow rate is 30 sccm, the sputtering voltage is 380 V, the current is 50 mA, the sputtering time is 30 min, and the target is a metal zinc target; the thickness of the prepared zinc oxide thin film is 120 nm.

[0044] Step (3). Put the product of Step (3) into the quartz tube of the tube furnace, fill it with the inert gas argon, heat the quartz tube, the heating rate of the quartz tube is 20 °C / min, rise to 800 °C, and keep it warm for 90 min, and then the quartz tube cools naturally to room temperature to obtain a heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide.

[0045] Example 5:

[0046] Step (1). Prepare a cuprous phosphide thin film; specifically including the following steps:

[0047] Step ①. Put sodium hypophosphite into a corundum boat, and then cover the surface of the corundum boat with a copper foil having an area of 5 square centimeters and a thickness of 800 micrometers; the copper foil is a copper thin film on the surface of aluminum oxide.

[0048] Step ②. Put the corundum boat into a corundum tube, evacuate it, then fill it with argon at 1 atmospheric pressure, and then seal both ends of the corundum tube.

[0049] Step ③. Heat the corundum tube to 300 °C in a tube furnace at a heating rate of 10 °C / min; after the temperature rises to 300 °C, keep it warm for 45 min; then cool it naturally to room temperature, evacuate the corundum tube to remove the residual gas inside the tube, and then take out the product cuprous phosphide thin film.

[0050] Step (2). A mask plate is placed on the surface of the cuprous phosphide thin film, and a zinc oxide thin film is deposited by magnetron sputtering. The zinc oxide thin film is in the shape of interdigital electrodes; the vacuum degree of the magnetron sputtering equipment is 0.9 Pa, the oxygen flow rate is 4 sccm, the argon flow rate is 30 sccm, the sputtering voltage is 450 V, the current is 60 mA, the sputtering time is 40 min, and the target is a metallic zinc target; the thickness of the prepared zinc oxide thin film is 180 nm;

[0051] Step (3). The product of step (3) is placed in a quartz tube of a tube furnace, and inert gas argon is filled. The quartz tube is heated, and the heating rate of the quartz tube is 20 °C / min. It is heated to 850 °C and held for 120 min, and then the quartz tube is naturally cooled to room temperature to obtain a heterojunction formed by p-type cuprous oxide and p-type cuprous phosphide.

Claims

1. A method for preparing a cuprous oxide - cuprous phosphide heterojunction, characterized in that, the method specifically comprises the following steps: Step (1). Prepare a cuprous phosphide thin film; Step (2). Place a mask on the surface of the cuprous phosphide thin film, and deposit a zinc oxide thin film by magnetron sputtering. The zinc oxide thin film is in the shape of interdigital electrodes; the vacuum degree of the magnetron sputtering equipment is 0.1 - 1.0 Pa, the oxygen flow rate is 1 - 5 sccm, the argon flow rate is 20 - 50 sccm, the sputtering voltage is 300 - 450 V, the current is 30 - 60 mA, the sputtering time is 20 - 40 min, and the target is a metallic zinc target; the thickness of the prepared zinc oxide thin film is 50 - 200 nm; Step (3). Put the product of Step (2) into the quartz tube of a tube furnace, fill it with the inert gas argon, heat the quartz tube, the heating rate of the quartz tube is 20 °C / min, raise the temperature to 760 - 850 °C, and keep it warm for 60 - 120 min, and then the quartz tube is naturally cooled to room temperature to obtain a heterojunction formed by p - type cuprous oxide and p - type cuprous phosphide.

2. The method for preparing a cuprous oxide - cuprous phosphide heterojunction according to claim 1, characterized in that: The preparation of the cuprous phosphide thin film specifically comprises the following steps: Step (1). Put sodium hypophosphite into a corundum boat, and then cover the surface of the corundum boat with a copper foil with a thickness of 250 - 1000 microns; Step (2). Put the corundum boat into a corundum tube, evacuate it, and then fill it with argon at 1 atmospheric pressure, and then seal both ends of the corundum tube; Step (3). Heat the corundum tube to 280 - 300 °C by a tube furnace, with a heating rate of 10 °C / min; after the temperature rises to 280 - 300 °C, keep it warm for 30 - 60 min; then naturally cool it to room temperature, evacuate the corundum tube to remove the residual gas in the tube, and then take out the product, the cuprous phosphide thin film.

3. The method for preparing a cuprous oxide - cuprous phosphide heterojunction according to claim 2, characterized in that: The copper foil is replaced with a copper thin film grown on the surface of alumina or silica.

4. The method for preparing a cuprous oxide - cuprous phosphide heterojunction according to claim 2, characterized in that: The area of the copper foil is 1 - 5 square centimeters.

5. The method for preparing a cuprous oxide - cuprous phosphide heterojunction according to claim 2, characterized in that: The thickness of the copper foil is 600 microns.

6. The method for preparing a cuprous oxide - cuprous phosphide heterojunction according to claim 2, characterized in that: The conduction type of the cuprous phosphide is p - type, and the conduction type of the cuprous oxide is p - type.

Images