A gallium nitride photoelectrode modified by cobalt oxide and cuprous oxide for enhancing photocurrent, a preparation method and applications thereof

Abstract

The application discloses a cobalt oxide and cuprous oxide modified gallium nitride photoelectrode for enhancing photoelectric current, a preparation method and application, and belongs to the technical field of electrodes. The preparation process of the photoelectrode comprises the following steps: after an n-GaN wafer is cut, the n-GaN wafer is washed and then dried by blowing; Co(NO3)2, NaIO3 and methanol are mixed to form a solution A, then the n-GaN wafer is placed in the solution A, and then photo-deposition is carried out under ultraviolet light; after washing, the n-GaN wafer is dried by using nitrogen, and thus an n-GaN wafer sample with Co3O4 nanoparticles is obtained; a Na2SO3 aqueous solution and a CuSO4 aqueous solution are mixed and stirred to obtain a solution B; the n-GaN wafer sample with Co3O4 nanoparticles is hung in the solution B and heated in a water bath, and a NaOH solution is added dropwise, then the n-GaN wafer sample is washed and dried by using nitrogen, and thus a cobalt oxide and cuprous oxide modified gallium nitride photoelectrode is obtained; the cobalt oxide and cuprous oxide modified gallium nitride photoelectrode is dried and shaped, and thanks to reasonable Co3O4 / Cu2O decoration, high response and fast response / recovery time are realized under 365nm light.

Description

Technical Field

[0001] This invention belongs to the field of electrode technology, specifically relating to a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent, its preparation method, and its application. Background Technology

[0002] Ultraviolet (UV) photodetectors have garnered widespread attention in environmental monitoring, biomedicine, and intelligent optoelectronic devices due to their advantages such as energy efficiency, miniaturization, and high integration. With the increasing demand for highly integrated and multifunctional photodetectors in both military and civilian applications, high-performance, miniaturized, and low-dimensional UV photodetectors have become a new research hotspot. In recent years, various UV photodetectors based on materials such as ZnO, ZnS, NiO, and GaN have been studied. Among them, GaN, due to its superior properties, such as inherently suitable bandgap for UV photosensitivity, high carrier mobility, and good chemical and thermal stability, is considered a promising candidate for developing high-performance UV photodetectors and has broad prospects in the field of UV photodetection.

[0003] Therefore, there is an urgent need to find a simple method to improve the carrier mobility efficiency of gallium nitride-based photoelectrodes. Research on carrier dynamics manipulation in semiconductor devices mainly focuses on two active areas. On the one hand, a large amount of research concentrates on exploring new structures in semiconductors, whether using semiconductor heterojunctions or quantum structures such as quantum wells / points / lines to confine or modulate carrier transport behavior. More importantly, on the other hand, controlling the interaction between the semiconductor surface and its surrounding environment—that is, controlling the interfacial physicochemical properties and interfacial carrier behavior—is crucial for further optimizing device performance or exploring new functions. To achieve superior surface properties in these devices, strategic surface modification is often carried out by loading cocatalysts (i.e., functional nanoparticles or layers). Although there are many reports on various cocatalysts, the selection of cocatalyst materials should be cautious. Inappropriate materials can rapidly increase interfacial states and undesirable internal stresses, leading to deterioration of device performance. Furthermore, there is still room for optimization in the thickness, morphology, and crystal quality of the loaded cocatalyst to further improve device performance. Precise surface modification, enabling devices to possess ideal surface physicochemical properties, is key to pursuing PEC devices with excellent performance and new functions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent, its preparation method, and its application, thereby solving the problems in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent includes the following steps:

[0007] After dicing, rinsing, and drying the n-GaN wafer, Co(NO3)2, NaIO3, and methanol were mixed to prepare solution A. The n-GaN wafer was then placed in solution A and photodeposited under ultraviolet light. After rinsing, it was dried with nitrogen to obtain an n-GaN wafer sample with Co3O4 nanoparticles.

[0008] Solution B was obtained by mixing and stirring Na2SO3 aqueous solution and CuSO4 aqueous solution; n-GaN wafer sample with Co3O4 nanoparticles was suspended in solution B and heated in a water bath, and NaOH solution was added dropwise. After rinsing, it was dried with nitrogen to obtain gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide.

[0009] Gallium nitride photoelectrodes modified with cobalt oxide and cuprous oxide were dried and shaped.

[0010] Furthermore, when preparing solution A, the molar ratio of Co(NO3)2 to NaIO3 is 1:1.

[0011] Furthermore, the volume ratio of Co(NO3)2, NaIO3, and methanol is 1:1:3.

[0012] Furthermore, the molar ratio of Na2SO3 to CuSO4 is 1:1.

[0013] Furthermore, the concentration of the NaOH solution is 10 mg / ml.

[0014] Furthermore, the Na2SO3 aqueous solution and CuSO4 aqueous solution were mixed and stirred at a rate of 100 r / min for 6 min; the water bath heating temperature was 70℃ for 25 min.

[0015] Furthermore, the photodeposition time is 15 minutes.

[0016] Furthermore, the drying and shaping of the photoelectrode is carried out in an oven at a temperature of 80°C for 2 hours.

[0017] A gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent is prepared using the above-described method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent.

[0018] The above-mentioned application of gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent in photodetectors.

[0019] The beneficial effects of this invention are:

[0020] 1. This invention develops a highly efficient modulated ultraviolet photoelectrode based on a Co3O4 / Cu2O / n-GaN dual oxide. Since the band structure of GaN is lower than that of Co3O4 / Cu2O, this structure plays a crucial role in accelerating the transport of photogenerated carriers. Thanks to the appropriate Co3O4 / Cu2O decoration, high response and fast response / recovery time are achieved under 365nm illumination.

[0021] 2. The sample required for this invention is an n-GaN nanofilm. Gallium nitride film is grown on a sapphire substrate using metal-organic chemical vapor deposition (MOCVD) technology. This structure has good stability and stable photocurrent. The effect is significantly improved after modification with Co3O4 / Cu2O, and the response is several times higher than that of the original n-type gallium nitride film. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of the method for preparing the photoelectrode according to the present invention.

[0024] Figure 2 This is a SEM image of the sample from Example 1 of this invention;

[0025] Figure 3 This is a comparison graph of the it at 365nm and 0V of the sample in Example 1 of this invention with those of Comparative Examples 1 and 2.

[0026] Figure 4 This is a comparison graph of the it at 0V at 365nm for the sample of Example 1 in this invention and that of Comparative Example 3.

[0027] Figure 5 This is a comparison graph of the it at 365nm and 0V of the sample in Example 1 of this invention and Comparative Example 4.

[0028] Figure 6 The image shows the it graphs of the sample from Example 1 of this invention under different light intensities at 365nm illumination.

[0029] Figure 7 This is an it graph of the sample in Example 1 of this invention under 365nm illumination with applied bias voltage. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] A method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent includes the following steps:

[0032] S1. Cut the n-GaN (n-type gallium nitride) wafer to the required size, rinse it several times with ethanol and deionized water, and then blow it dry. Mix Co(NO3)2, NaIO3 and methanol to prepare solution A, then put the n-GaN wafer into solution A, and then perform photodeposition under ultraviolet light. After rinsing with ethanol and deionized water and drying with nitrogen, an n-GaN wafer sample with Co3O4 nanoparticles is obtained.

[0033] S2, Na2SO3 aqueous solution is added to CuSO4 aqueous solution and stirred evenly (while stirring, Na2SO3 aqueous solution is slowly added to CuSO4 aqueous solution dropwise multiple times with a pipette) to obtain solution B; then, the n-GaN wafer sample with Co3O4 nanoparticles is suspended in solution B and placed in a water bath for heating. While heating, NaOH solution is added to solution B dropwise with a pipette. After the time is up, it is taken out, rinsed with ethanol and deionized water, and then dried with nitrogen to obtain gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide.

[0034] S3, place the gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide into an oven for drying and shaping;

[0035] In S1, when preparing solution A, the molar ratio of Co(NO3)2 to NaIO3 is 1:1, and the volume ratio of Co(NO3)2, NaIO3 to methanol is 1:1:3.

[0036] In S1, the photodeposition time is 15 min.

[0037] In S2, the molar ratio of Na2SO3 to CuSO4 is 1:1.

[0038] In S2, the concentration of NaOH solution is 10 mg / ml.

[0039] In S2, the stirring rate is 100 r / min and the stirring time is 6 min; the water bath temperature is 70℃ and the heating time is 25 min.

[0040] In S3, the oven temperature is 80℃ and the time is 2 hours.

[0041] In gallium nitride photoelectrodes modified with cobalt oxide and cuprous oxide, the cuprous oxide particles are 100 nm to 500 nm in size.

[0042] In this invention, a high-speed nanostructured photoelectrode reconstruction based on an n-GaN nanofilm with a rational Co3O4 / Cu2O structure was developed using a combination of photodeposition and hydrothermal method. First, cobalt tetroxide was uniformly distributed onto the surface of the gallium nitride photoelectrode via photodeposition, and then cuprous oxide particles were attached to the surface using a hydrothermal method.

[0043] The technical solution of the present invention will be described in detail below through the following embodiments and comparative examples;

[0044] Example 1

[0045] like Figure 1 As shown, a method for fabricating a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent is disclosed. The fabrication method includes the following steps:

[0046] S1, cut the n-GaN wafer to 1cm. 2 *1cm 2 The size was determined by rinsing with ethanol and deionized water 2-3 times and then drying. Solution A was prepared by mixing 0.2 mol of Co(NO3)2, 0.2 mol of NaIO3, and 6 ml of methanol. The n-GaN wafer was then placed in solution A and photodeposited under UV light for 15 min. After rinsing with ethanol and deionized water and drying with nitrogen, an n-GaN wafer sample containing Co3O4 nanoparticles was obtained.

[0047] S2, 0.05 mol Na2SO3 aqueous solution was added to 0.05 mol CuSO4 aqueous solution (with a stirring rate of 100 r / min and a stirring time of 6 min, the Na2SO3 aqueous solution was slowly added to the CuSO4 aqueous solution multiple times using a pipette) to obtain solution B. Then, an n-GaN wafer sample containing Co3O4 nanoparticles was suspended in solution B and placed in a water bath at 70℃ for 25 min. During heating, 3 ml of 10 mg / ml NaOH solution was added to solution B using a dropper. After removal, the sample was rinsed with ethanol and deionized water and then dried with nitrogen to obtain a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide.

[0048] S3, the gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide was placed in an oven at 80°C for drying and shaping for 2 hours; its SEM image is shown below. Figure 2 As shown.

[0049] Comparative Example 1

[0050] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 is a common gallium nitride thin film photoelectrode, without the addition of cobalt tetroxide and cuprous oxide for modification on the gallium nitride.

[0051] Comparative Example 2

[0052] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, cobalt tetroxide is attached to the gallium nitride thin film photoelectrode, but cuprous oxide is not attached for modification, and step S2 in Example 1 is not performed.

[0053] Comparative Example 3

[0054] The difference between Comparative Example 3 and Example 1 is that in S2, 0.05 mol of Na2SO3 aqueous solution was added to 0.1 mol of CuSO4 aqueous solution (with a stirring rate of 100 r / min and a stirring time of 6 min, the Na2SO3 aqueous solution was slowly added to the CuSO4 aqueous solution multiple times using a pipette) to obtain solution B. Then, an n-GaN wafer sample containing Co3O4 nanoparticles was suspended in solution B and placed in a water bath at 70°C for 25 min. During heating, 3 ml of 10 mg / ml NaOH solution was added to solution B using a dropper. After the time was up, the sample was removed, rinsed with ethanol and deionized water, and then dried with nitrogen to obtain a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide.

[0055] Comparative Example 4

[0056] The only difference between Comparative Example 4 and Example 1 is that the modified sample was not dried and shaped in S3.

[0057] Experimental Test

[0058] The gallium nitride photoelectrodes prepared in Example 1 and Comparative Examples 1-4 were subjected to performance testing. During the testing, the current, voltage and other properties of the samples were tested using an electrochemical workstation 760e.

[0059] The specific testing steps are as follows: Sodium sulfate solution was used as the electrolyte, with the sample to be tested as the working electrode, a silver / silver chloride electrode as the reference electrode, and a platinum mesh electrode as the counter electrode. To simulate the illumination conditions of the reagent, an LED bead with a wavelength of 365nm was selected as the light source. The shutter speed was used to simulate the occurrence and deactivation of the light, thus precisely controlling the time.

[0060] Figure 3 The figure shows a comparison of the current density (it) at 0V at 365nm for the sample of Example 1 and Comparative Examples 1 and 2. It can be seen from the figure that the current density of the n-type gallium nitride with deposited cobalt oxide and cuprous oxide is higher than that of the bare n-type gallium nitride and the n-type gallium nitride with only deposited cobalt oxide.

[0061] Figure 4The figure shows a comparison of the current density at 0V at 365nm between the sample of Example 1 and Comparative Example 3. It can be seen from the figure that the current density of Example 1 is much higher than that of Comparative Example 3. Therefore, the optimal molar ratio of Na2SO3 to CuSO4 in S2 is 1:1.

[0062] Figure 5 The figure shows a comparison of the current density at 0V at 365nm between the sample of Example 1 and Comparative Example 4. It can be seen from the figure that the current density of Example 1 is greater than that of Comparative Example 4, so the drying and shaping in Example 1 is an extremely important step.

[0063] Figure 6 The figure shows the it graph of the sample of Example 1 under different light intensities under 365nm illumination. It can be seen from the figure that the intensity of the light source in Example 1 fluctuates proportionally with the illumination of different power light sources.

[0064] Figure 7 The figure shows the it graph of the sample of Example 1 under 365nm illumination with applied bias voltage. As can be seen from the figure, Example 1 can be controlled and adjusted by bias voltage, and can be better applied to practical applications.

[0065] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent, characterized in that, Includes the following steps: After dicing, rinsing, and drying the n-GaN wafer, Co(NO3)2, NaIO3, and methanol were mixed to prepare solution A. The n-GaN wafer was then placed in solution A and photodeposited under ultraviolet light. After rinsing, it was dried with nitrogen to obtain an n-GaN wafer sample with Co3O4 nanoparticles. Solution B was obtained by mixing and stirring Na2SO3 aqueous solution and CuSO4 aqueous solution; n-GaN wafer sample with Co3O4 nanoparticles was suspended in solution B and heated in a water bath, and NaOH solution was added dropwise. After rinsing, it was dried with nitrogen to obtain gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide. Gallium nitride photoelectrodes modified with cobalt oxide and cuprous oxide were dried and shaped.

2. The method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent according to claim 1, characterized in that, When preparing solution A, the molar ratio of Co(NO3)2 to NaIO3 is 1:

1.

3. The method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent according to claim 1, characterized in that, The volume ratio of Co(NO3)2, NaIO3 and methanol is 1:1:

3.

4. The method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent according to claim 1, characterized in that, The molar ratio of Na2SO3 to CuSO4 is 1:

1.

5. The method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent according to claim 1, characterized in that, The concentration of the NaOH solution is 10 mg / ml.

6. The method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent according to claim 1, characterized in that, The Na2SO3 aqueous solution and CuSO4 aqueous solution were mixed and stirred at a rate of 100 r / min for 6 min; the water bath heating temperature was 70℃ for 25 min.

7. The method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent according to claim 1, characterized in that, The photodeposition time was 15 minutes.

8. The method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent according to claim 1, characterized in that, The photoelectrode is dried and shaped in an oven at 80°C for 2 hours.

9. A gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent, characterized in that, It was prepared using the method for preparing a gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent as described in any one of claims 1-8.

10. The application of the gallium nitride photoelectrode modified with cobalt oxide and cuprous oxide to enhance photocurrent as described in claim 9 in a photodetector.

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