Self-driven photoelectric detector with gradient energy band and preparation method thereof
By using two-dimensional molybdenum carbide and two-dimensional titanium carbide transparent electrodes that do not contact each other in the self-driven photodetector, a gradient energy band structure is formed, and the problem of similar work functions of metal electrodes in the prior art is solved, and zero is achieved High-responsive self-driven photodetection at bias voltage, suitable for low-power applications.
Patent Information
- Application Number
- CN202411275370.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2024-12-27
AI Technical Summary
Among the existing self-driven photodetectors, common metal electrode materials have similar work functions, making it difficult to achieve an asymmetric contact structure with large differences in work functions, which limits the effective separation of photogenerated electron-hole pairs and the generation of self-driven photocurrent.
The two-dimensional molybdenum carbide and two-dimensional titanium carbide transparent electrodes that do not contact each other are used on the gallium arsenide substrate. The gradient energy band structure is prepared through photolithography and inkjet printing technology, and the step arrangement is formed by using the difference in work function. Built-in electric field to realize high-responsive self-drive detection under zero bias.
Highly responsive self-driven photodetection at zero bias is achieved, simplifying process and reducing costs, suitable for low power and portable applications.
Smart Images
Figure CN119208405A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of photoelectric detectors, and more specifically, to a self-driven photoelectric detector with a gradient energy band and a preparation method thereof. Background Art
[0002] Self-driven photodetectors are light-sensitive devices that do not require external power to operate. They use the photovoltaic effect generated by the built-in electric field to generate current signals. This feature makes self-driven photodetectors very suitable for low-power and portable applications, such as wireless sensor networks, biomedical monitoring, and environmental monitoring.
[0003] Asymmetric work function metal contact is an effective method to realize self-driven photodetectors. When two metals with different work functions form Schottky contacts with semiconductor materials, built-in electric fields are generated at the interfaces. The direction of the built-in electric field at the interface depends on the work function of the semiconductor and the metal. If the directions of the built-in electric fields at the two interfaces are consistent and the difference in the work function of the metals is large enough, the photogenerated electron-hole pairs can be effectively separated, thereby generating a self-driven photocurrent.
[0004] However, the work functions of common metal electrode materials are similar and relatively high, making it difficult to achieve an asymmetric contact structure with large differences in work functions. Summary of the invention
[0005] In view of this, the present disclosure provides a self-driven photodetector with a gradient energy band and a preparation method thereof.
[0006] A first aspect of the present disclosure provides a self-driven photodetector with a gradient energy band, comprising: a gallium arsenide substrate; a first transparent electrode and a second transparent electrode, both of which are arranged on the gallium arsenide substrate, and the first transparent electrode and the second transparent electrode are not in contact with each other; wherein the material of the first transparent electrode is two-dimensional molybdenum carbide, and the material of the second transparent electrode is two-dimensional titanium carbide; the work function of the first transparent electrode, the work function of the gallium arsenide substrate and the work function of the second transparent electrode form a stepped arrangement.
[0007] According to an embodiment of the present disclosure, the first transparent electrode, the gallium arsenide substrate and the second transparent electrode form a gradient energy band structure.
[0008] According to an embodiment of the present disclosure, the interval between the first transparent electrode and the second transparent electrode is 1 μm-3 μm.
[0009] According to an embodiment of the present disclosure, the length×width of the first transparent electrode and the second transparent electrode are both 200 μm×100 μm, and the thickness is both 100 nm-150 nm.
[0010] On the other hand, the present disclosure provides a method for preparing a self-driven photodetector with a gradient energy band, comprising: preparing a first transparent electrode and a second transparent electrode on a gallium arsenide substrate, wherein the first transparent electrode and the second transparent electrode do not contact each other, the material of the first transparent electrode is a two-dimensional molybdenum carbon compound, and the material of the second transparent electrode is a two-dimensional titanium carbide; the work function of the first transparent electrode, the work function of the gallium arsenide substrate, and the work function of the second transparent electrode form a stepped arrangement.
[0011] According to an embodiment of the present disclosure, a first transparent electrode and a second transparent electrode are prepared on a gallium arsenide substrate, including: using photolithography technology to form a first transparent electrode window on the gallium arsenide substrate; coating a two-dimensional molybdenum carbide solution on the gallium arsenide substrate having the first transparent electrode window to obtain a first transparent electrode film; subjecting the first transparent electrode film to an immersion stripping treatment to obtain a first transparent electrode; on the gallium arsenide substrate having the first transparent electrode, using photolithography technology to obtain a second transparent electrode window that does not contact the first transparent electrode; coating a two-dimensional titanium carbide solution on the gallium arsenide substrate having the second transparent electrode window to obtain a second transparent electrode film; subjecting the second transparent electrode film to an immersion stripping treatment to obtain a second transparent electrode.
[0012] According to an embodiment of the present disclosure, a first transparent electrode film is subjected to an immersion stripping treatment to obtain a first transparent electrode, and a second transparent electrode film is subjected to an immersion stripping treatment to obtain a second transparent electrode, comprising: firstly soaking a gallium arsenide substrate having the first transparent electrode film and a gallium arsenide substrate having the second transparent electrode film in acetone for 10s-30s, and then soaking them in isopropanol for 10s-30s, and after stripping treatment, respectively obtaining the first transparent electrode and the second transparent electrode.
[0013] According to an embodiment of the present disclosure, a two-dimensional molybdenum carbide solution is coated on a gallium arsenide substrate having a first transparent electrode window to obtain a first transparent electrode film; and a two-dimensional titanium carbide solution is coated on a gallium arsenide substrate having a second transparent electrode window to obtain a second transparent electrode film, comprising: firstly subjecting the gallium arsenide substrate having the first transparent electrode window and the gallium arsenide substrate having the second transparent electrode window to a hydrophilic treatment using oxygen plasma; then coating the gallium arsenide substrate having the first transparent electrode window that has been hydrophilically treated with a two-dimensional molybdenum carbide solution to obtain a first transparent electrode film; and coating the gallium arsenide substrate having the second transparent electrode window that has been hydrophilically treated with a two-dimensional titanium carbide solution to obtain a second transparent electrode film; wherein the power of the oxygen plasma is 100w-200w, the plasma vacuum is 30Pa-80Pa, the oxygen flow rate is 100sccm-200sccm, and the treatment time is 1min-2min.
[0014] According to an embodiment of the present disclosure, the concentration of the two-dimensional molybdenum carbide solution and the concentration of the two-dimensional titanium carbide solution are both 1.25 mg / mL.
[0015] According to an embodiment of the present disclosure, it also includes: using inkjet printing technology to spray silver nanoparticle ink on the edge of the first transparent electrode and the edge of the second transparent electrode to print two contact electrodes with a line width of 300μm-1000μm.
[0016] According to the embodiments of the present disclosure, the work function of the first transparent electrode, the work function of the gallium arsenide substrate and the work function of the second transparent electrode form a stepped arrangement, and after contact, two Schottky junctions with consistent built-in electric field directions are formed, thereby achieving high-response self-driven detection under zero bias.
[0017] According to the embodiments of the present disclosure, both transparent electrodes are prepared by using a photolithography lift-off process, which is simple and can be applied to the preparation of large-scale patterned arrays of wafer-level MXene films. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:
[0019] Figure 1 The schematic diagram of the structure of the photoelectric detector according to the embodiment of the present disclosure is shown;
[0020] Figure 2 Schematically shows the ultraviolet photoelectron spectrum of the first transparent electrode and the second transparent electrode according to the embodiment of the present disclosure;
[0021] Figure 3 The energy band structure diagram before the first transparent electrode, the second transparent electrode and the substrate contact each other is schematically shown according to an embodiment of the present disclosure;
[0022] Figure 4 The energy band structure diagram after the first transparent electrode, the second transparent electrode and the substrate are in contact is schematically shown according to an embodiment of the present disclosure;
[0023] Figure 5 The process flow chart of a photodetector according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION
[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.
[0025] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.
[0026] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.
[0027] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).
[0028] Figure 1 The structural diagram of the photodetector according to the embodiment of the present disclosure is schematically shown.
[0029] Figure 2 The ultraviolet photoelectron spectrum of the first transparent electrode and the second transparent electrode according to the embodiment of the present disclosure is schematically shown.
[0030] Figure 3 The energy band structure diagram of the first transparent electrode, the second transparent electrode and the substrate before contact according to an embodiment of the present disclosure is schematically shown.
[0031] Figure 4 The energy band structure diagram after the first transparent electrode, the second transparent electrode and the substrate are in contact according to an embodiment of the present disclosure is schematically shown.
[0032] like Figure 1As shown, the first aspect of the present disclosure provides a self-driven photodetector with a gradient energy band, comprising: a gallium arsenide substrate; a first transparent electrode and a second transparent electrode, both of which are arranged on the gallium arsenide substrate, and the first transparent electrode and the second transparent electrode are not in contact with each other; wherein the material of the first transparent electrode is two-dimensional molybdenum carbide, and the material of the second transparent electrode is two-dimensional titanium carbide; the work function of the first transparent electrode, the work function of the gallium arsenide substrate and the work function of the second transparent electrode form a stepped arrangement.
[0033] In the embodiment of the present disclosure, the material of the first transparent electrode is two-dimensional molybdenum carbide (Mo2CT x The material of the second transparent electrode is two-dimensional titanium carbide (Ti3C2T x ), are two MXene materials with large differences in work function, such as Figure 2 As shown, Mo2CT x The binding energy of Ti3C2T is 15.98eV. x The binding energy of Mo2CT is 16.89 eV, which can be obtained x The work function of Ti3C2T is 5.24eV. x The work function of Mo2CT is 4.33eV. x , substrate, Ti3C2T x The work functions of the three materials are arranged from large to small, and a gradient structure of energy bands is formed after the materials come into contact, thus realizing the high-response self-driven detection of the MSM dual Schottky detector under zero bias.
[0034] According to an embodiment of the present disclosure, the gallium arsenide substrate is an intrinsic gallium arsenide substrate.
[0035] like Figure 3 and Figure 4 As shown in the figure, before contact, since the substrate is an intrinsic GaAs substrate, the Fermi level of GaAs can be regarded as being in the middle of the band gap, and the Fermi levels of the three materials are distributed in a step-like manner. During the contact process, since there is a work function difference between the two MXene materials and the GaAs substrate, Schottky contact will be formed after contact.
[0036] At the same time, the direction of the built-in electric field is consistent at the interface where the two transparent electrodes contact the GaAs substrate, which points from the low energy band to the high energy band. Therefore, the built-in electric field will show a consistent direction in the whole, and it can work without external bias. Under light, the photogenerated carriers generated in the GaAs substrate will be swept to different electrodes under the action of the built-in electric field, generating photocurrent.
[0037] According to an embodiment of the present disclosure, the first transparent electrode, the gallium arsenide substrate and the second transparent electrode form a gradient energy band structure.
[0038] In the embodiments of the present disclosure, since the work functions of the MXene materials on both sides are different and there is a large difference, in order to form an equilibrium state, the flow of carriers causes the three materials to form a unified Fermi level. Therefore, after contact, the energy bands at the interface between the gallium arsenide substrate and the two MXenes bend in different directions, forming a stepped band structure.
[0039] According to an embodiment of the present disclosure, the interval between the first transparent electrode and the second transparent electrode is 1 μm-3 μm.
[0040] According to an embodiment of the present disclosure, the length×width of the first transparent electrode and the second transparent electrode are both 200 μm×100 μm, and the thickness is both 100 nm-150 nm.
[0041] According to an embodiment of the present disclosure, it further includes: two silver contact electrodes, which are respectively arranged on the first transparent electrode and the second transparent electrode.
[0042] On the other hand, the present disclosure provides a method for preparing a self-driven photodetector with a gradient energy band, comprising: preparing a first transparent electrode and a second transparent electrode on a substrate, wherein the first transparent electrode and the second transparent electrode do not contact each other, the material of the first transparent electrode is two-dimensional molybdenum carbide, and the material of the second transparent electrode is two-dimensional titanium carbide; the work function of the first transparent electrode, the work function of the substrate and the work function of the second transparent electrode form a stepped arrangement.
[0043] Figure 5 The process flow chart of a photodetector according to an embodiment of the present disclosure is schematically shown.
[0044] like Figure 5 As shown, according to an embodiment of the present disclosure, a first transparent electrode and a second transparent electrode are prepared on a substrate, including:
[0045] Using photolithography technology, forming a first transparent electrode window on the substrate;
[0046] A two-dimensional molybdenum carbide solution is coated on a substrate having a first transparent electrode window to obtain a first transparent electrode film; the first transparent electrode film is subjected to an immersion stripping treatment to obtain a first transparent electrode;
[0047] On the substrate having the first transparent electrode, a second transparent electrode window which is not in contact with the first transparent electrode is obtained by using photolithography technology;
[0048] A two-dimensional titanium carbide solution is coated on a substrate with a second transparent electrode window to obtain a second transparent electrode film; and the second transparent electrode film is subjected to an immersion and stripping treatment to obtain a second transparent electrode.
[0049] In the embodiments of the present disclosure, the first transparent electrode and the second transparent electrode are both made by photolithography and stripping processes, so as to realize the preparation of patterned MXene films of micro-nano size, which can be applied to the preparation of large-scale arrays of wafer-level MXene films. At the same time, the thin films of the first transparent electrode and the second transparent electrode are both prepared by a solution method. Therefore, the preparation method of the self-driven photodetector with gradient energy band disclosed in the present disclosure has strong universality, simple process and low cost.
[0050] According to an embodiment of the present disclosure, a first transparent electrode film is subjected to an immersion stripping treatment to obtain a first transparent electrode, and a second transparent electrode film is subjected to an immersion stripping treatment to obtain a second transparent electrode, comprising: firstly soaking a gallium arsenide substrate having the first transparent electrode film and a gallium arsenide substrate having the second transparent electrode film in acetone for 10s-30s, and then soaking them in isopropanol for 10s-30s, and after stripping treatment, respectively obtaining the first transparent electrode and the second transparent electrode.
[0051] According to an embodiment of the present disclosure, a two-dimensional molybdenum-carbon compound solution is coated on a substrate having a first transparent electrode window to obtain a first transparent electrode film; and a two-dimensional titanium carbide solution is coated on a substrate having a second transparent electrode window to obtain a second transparent electrode film, comprising: firstly subjecting the substrate having the first transparent electrode window and the substrate having the second transparent electrode window to a hydrophilic treatment using oxygen plasma; then coating the two-dimensional molybdenum carbide solution on the hydrophilic treated substrate having the first transparent electrode window to obtain the first transparent electrode film; and coating the two-dimensional titanium carbide solution on the hydrophilic treated substrate having the second transparent electrode window to obtain the second transparent electrode film; wherein the power of the oxygen plasma is 100w-200w, the plasma vacuum is 30Pa-80Pa, the oxygen flow rate is 100sccm-200sccm, and the treatment time is 1min-2min.
[0052] According to an embodiment of the present disclosure, the concentration of the two-dimensional molybdenum carbide solution and the concentration of the two-dimensional titanium carbide solution are both 1.25 mg / mL.
[0053] According to an embodiment of the present disclosure, it also includes: using inkjet printing technology to spray silver nanoparticle ink on the edge of the first transparent electrode and the edge of the second transparent electrode to print two contact electrodes with a line width of 300μm-1000μm.
[0054] The present disclosure provides an embodiment of a method for preparing a self-driven photodetector with a gradient energy band, comprising:
[0055] Step 1: Cut the intrinsic gallium arsenide substrate into a suitable size using a dicing machine, and ultrasonically clean it with acetone, isopropanol, and deionized water in sequence, and blow dry it with a N2 gun for later use.
[0056] Step 2: Using photolithography technology, a photoresist with a thickness of 2 μm-3 μm is coated on the surface of the gallium arsenide substrate, and after exposure and development treatment, a first transparent electrode window is obtained.
[0057] Step three: The gallium arsenide substrate with the first transparent electrode window is subjected to a hydrophilic treatment using oxygen plasma; wherein the parameters of the oxygen plasma are: the power is 100 W, the plasma vacuum is 50 Pa, the oxygen flow rate is 150 sccm, and the treatment time is 1 min; a 1.25 mg / mL two-dimensional molybdenum carbide solution is drop-coated on the hydrophilic treated gallium arsenide substrate, and dried under a room temperature N2 environment to obtain a two-dimensional molybdenum carbide film.
[0058] Step 4: The gallium arsenide substrate with the two-dimensional molybdenum carbide film is first immersed in acetone for 10 seconds and then immersed in isopropanol for 15 seconds for cleaning. After stripping, a first transparent electrode is obtained.
[0059] Step 5: On the surface of the gallium arsenide substrate having the first transparent electrode, a photoresist with a thickness of 2 μm-3 μm is coated by photolithography technology, and then subjected to exposure and development treatment to obtain a two-dimensional titanium carbide transparent electrode window that is not in contact with the first transparent electrode.
[0060] Step 6: After the gallium arsenide substrate with a two-dimensional titanium carbide transparent electrode window is hydrophilized, 1.25 mg / mL of the two-dimensional titanium carbide solution is drop-coated on the gallium arsenide substrate with a two-dimensional titanium carbide transparent electrode window after the hydrophilization treatment, and dried under a room temperature N2 environment to obtain a two-dimensional titanium carbide film; wherein, the hydrophilic treatment process in this step is consistent with the hydrophilic treatment process in step three, and the specific process parameters are shown in step three;
[0061] Step 7: The gallium arsenide substrate with the two-dimensional titanium carbide film is first immersed in acetone for cleaning for 10 seconds, and then immersed in isopropanol for 15 seconds for cleaning, and after stripping treatment, a second transparent electrode is obtained;
[0062] Step 8: Using inkjet printing technology, spray silver nanoparticle ink on the edge of the first transparent electrode and the edge of the second transparent electrode respectively, and print two silver electrodes with a line width of 600 μm as contact electrodes.
[0063] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.
Claims
1. A self-driven photodetector with gradient energy band, characterized in that: include: Gallium arsenide substrate; A first transparent electrode and a second transparent electrode are both arranged on the gallium arsenide substrate, and the first transparent electrode and the second transparent electrode do not contact each other; wherein the material of the first transparent electrode is two-dimensional molybdenum carbide, and the material of the second transparent electrode is two-dimensional titanium carbide; the work function of the first transparent electrode, the work function of the gallium arsenide substrate and the work function of the second transparent electrode form a stepped arrangement.
2. The self-driven photodetector with gradient energy band according to claim 1, characterized in that: The first transparent electrode, the gallium arsenide substrate and the second transparent electrode form a gradient energy band structure.
3. The self-driven photodetector with gradient energy band according to claim 1 or 2, characterized in that: The interval between the first transparent electrode and the second transparent electrode is 1 μm-3 μm.
4. The self-driven photodetector with gradient energy band according to claim 3, characterized in that: The length×width of the first transparent electrode and the second transparent electrode are both 200 μm×100 μm, and the thickness is both 100 nm-150 nm.
5. A method for preparing a self-driven photodetector with a gradient energy band, characterized in that: include: A first transparent electrode and a second transparent electrode are prepared on a gallium arsenide substrate, wherein the first transparent electrode and the second transparent electrode do not contact each other, the material of the first transparent electrode is a two-dimensional molybdenum carbon compound, and the material of the second transparent electrode is a two-dimensional titanium carbide; the work function of the first transparent electrode, the work function of the gallium arsenide substrate, and the work function of the second transparent electrode form a stepped arrangement.
6. The method for preparing a self-driven photodetector with a gradient energy band according to claim 5, characterized in that: Preparing a first transparent electrode and a second transparent electrode on the gallium arsenide substrate, comprising: Using photolithography technology, forming a first transparent electrode window on the gallium arsenide substrate; Coating a two-dimensional molybdenum carbide solution on the gallium arsenide substrate having the first transparent electrode window to obtain a first transparent electrode film; The first transparent electrode film is subjected to an immersion and stripping treatment to obtain a first transparent electrode; On the gallium arsenide substrate having the first transparent electrode, a second transparent electrode window which is not in contact with the first transparent electrode is obtained by using photolithography technology; Coating a two-dimensional titanium carbide solution on the gallium arsenide substrate having the second transparent electrode window to obtain a second transparent electrode film; The second transparent electrode film is subjected to an immersion and stripping treatment to obtain a second transparent electrode.
7. The method for preparing a self-driven photodetector with a gradient energy band according to claim 6, characterized in that: The first transparent electrode film is subjected to a soaking and stripping treatment to obtain a first transparent electrode, and the second transparent electrode film is subjected to a soaking and stripping treatment to obtain a second transparent electrode, comprising: The gallium arsenide substrate with the first transparent electrode film and the gallium arsenide substrate with the second transparent electrode film are first immersed in acetone for 10s-30s and then immersed in isopropanol for 10s-30s. After stripping treatment, a first transparent electrode and a second transparent electrode are obtained respectively.
8. The method for preparing a self-driven photodetector with a gradient energy band according to claim 6, characterized in that: Coating a two-dimensional molybdenum carbide solution on the gallium arsenide substrate having the first transparent electrode window to obtain a first transparent electrode film; and coating a two-dimensional titanium carbide solution on the gallium arsenide substrate having the second transparent electrode window to obtain a second transparent electrode film, comprising: The gallium arsenide substrate having the first transparent electrode window and the gallium arsenide substrate having the second transparent electrode window are both subjected to a hydrophilic treatment using oxygen plasma; Then coating the hydrophilically treated gallium arsenide substrate having the first transparent electrode window with a two-dimensional molybdenum carbide solution to obtain a first transparent electrode film; and Coating a two-dimensional titanium carbide solution on the hydrophilically treated gallium arsenide substrate having the second transparent electrode window to obtain a second transparent electrode film; Among them, the power of the oxygen plasma is 100w-200w, the plasma vacuum is 30Pa-80Pa, the oxygen flow rate is 100sccm-200sccm, and the treatment time is 1min-2min.
9. The method for preparing a self-driven photodetector with a gradient energy band according to claim 6, characterized in that: The concentration of the two-dimensional molybdenum carbon compound solution and the concentration of the two-dimensional titanium carbide solution are both 1.25 mg / mL.
10. The method for preparing a self-driven photodetector with a gradient energy band according to claim 6, characterized in that: Also includes: By using inkjet printing technology, silver nanoparticle ink is sprayed on the edge of the first transparent electrode and the edge of the second transparent electrode to print two contact electrodes with a line width of 300 μm-1000 μm.