A perovskite nanowire radial junction based photodetector and a preparation method thereof
By fabricating perovskite nanowire radial junctions at low temperatures on glass or plastic substrates, the problem of high growth temperature of semiconductor nanowires has been solved, achieving efficient photoelectric detection, especially in applications on transparent substrates.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU YIHEGUANG ELECTRONIC TECH CO LTD
- Filing Date
- 2022-07-01
- Publication Date
- 2026-06-23
Smart Images
Figure CN114937746B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photoelectric detection, and particularly to high-efficiency photoelectric detection technology. Background Technology
[0002] Photodetector is a crucial step in information processing, utilizing the photoelectric effect to convert the information of incident light into electrical signals. Existing photodetectors all employ semiconductor thin films as the incident light absorber. If the detector substrate is a transparent substrate such as glass or plastic, it is impossible to grow a single-crystal film on it using epitaxial growth methods. Generally, amorphous semiconductor films are fabricated on glass or plastic substrates using methods such as sputtering or plasma-enhanced chemical vapor deposition. Because amorphous semiconductor films have a disordered structure, very low carrier mobility, and high defect density, photodetectors using amorphous semiconductor films exhibit low quantum efficiency and specific detectivity.
[0003] Compared to amorphous semiconductor films, semiconductor nanowires exhibit excellent lattice order and high carrier axial mobility, leading to the proposal to use semiconductor nanowires instead of amorphous semiconductor films in photodetector fabrication. However, due to the high dark current and noise of pure photoconductive detectors, junction detectors are typically employed. To address this, some research groups have proposed doping semiconductor nanowires to form planar pn junctions and fabricating corresponding junction photodetectors (NanoLett. 2020, 20, 887-895).
[0004] Besides the planar junction nanowire structures mentioned above, radial junction nanowire structures have also been proposed. A GaAs nanowire radial junction and detector structure (Nano Lett. 2021, 21, 9038-9043) exhibits good photovoltaic properties. However, because this GaAs nanowire requires a high fabrication temperature, it cannot be grown on glass or plastic substrates. Another research group has fabricated core-shell InGaN nanowires, obtaining radial junctions and realizing white light-emitting diodes (Nano Lett. 2020, 20, 4162-4168). Since InGaN nanowires require selective high-temperature epitaxy, they cannot be grown on glass substrates but are instead fabricated on sapphire substrates.
[0005] To address the issue of excessively high growth temperatures for many core-shell semiconductor nanowires, there is an urgent need to fabricate semiconductor nanowires on glass and plastic substrates and construct radial pn or pin junctions to obtain high-performance photodetectors. Summary of the Invention
[0006] The purpose of this invention is to address the problem that the growth temperature of inorganic semiconductor nanowires is too high, which cannot meet the requirements of transparent substrates such as glass and plastics. The invention aims to provide a method for preparing radial junctions of perovskite nanowires at low temperatures and constructing high-performance photodetectors.
[0007] The technical solution adopted in this invention is: a photodetector based on a radial junction of perovskite nanowires, comprising a detector substrate, a bottom electrode, a perovskite core nanowire, a first epitaxial shell of perovskite, a second epitaxial shell of perovskite, and a top electrode;
[0008] The perovskite core nanowires are either p-type or n-type perovskite nanowires.
[0009] The first epitaxial shell of the perovskite is an intrinsic epitaxial shell of perovskite, and the second epitaxial shell of the perovskite is an n-type epitaxial shell of perovskite or a p-type epitaxial shell of perovskite.
[0010] The perovskite core nanowire, the first perovskite epitaxial shell, and the second perovskite epitaxial shell constitute a radial pin junction.
[0011] The bottom electrode forms an ohmic contact with the perovskite core nanowire, and the top electrode forms an ohmic contact with the perovskite second epitaxial shell.
[0012] Alternatively, the first epitaxial shell can be set as an n-type layer or a p-type layer, which forms a pn junction with the perovskite core nanowire.
[0013] Preferably, the detector substrate is a transparent substrate, such as glass or plastic.
[0014] Preferably, the semiconductor properties of the perovskite core nanowire, the first perovskite epitaxial shell, and the second perovskite epitaxial shell can be controlled by changing the elemental composition. Typical p-type perovskite is MAPbBr3, intrinsic perovskite is MAPbBr2.5Cl0.5, and n-type perovskite is MAPbCl3. (There are many forms of p-type and n-type perovskites that can be controlled by composition; MAPbBr3 and MAPbCl3 are just commonly used structures.)
[0015] Alternatively, solution-based metal ion doping can be used to control the p- and n-type electrical properties of perovskites, typically with Bi doping. 3+ Mn 2+ Cu 2+ Sb 3+ Mg 2+ Metal ions form a perovskite n-type layer; Ag doping + Cs + Li + In 3+ Ba 2+Metal ions form a perovskite p-type layer.
[0016] Preferably, in order to make the pin radial junction interface have a matching lattice structure, several buffer layers can be inserted between the p-type layer, the intrinsic layer and the n-type layer, so that the lattice constant mismatch rate on both sides of the interface is less than 3%.
[0017] Alternatively, the intrinsic perovskite layer can be omitted, and an n-type layer can be grown directly around the p-type perovskite core nanowire to form a pn radial junction.
[0018] Alternatively, the perovskite core nanowires can be configured as n-type, and then intrinsic and p-type layers can be grown sequentially to form a nip radial junction or an np radial junction.
[0019] Preferably, to improve incident light transmittance, the top and bottom electrodes can be made of transparent electrode materials, such as ITO and FTO.
[0020] The perovskite nanowire radial junction photodetector proposed in this invention forms a depletion layer through a radial junction composed of a core nanowire and an epitaxial layer. When a photon is incident from the top, the incident light is absorbed by the depletion layer, and under the action of a bias electric field, photogenerated electron / hole pairs are separated, forming a probe current.
[0021] The above-mentioned method for fabricating a photodetector based on a perovskite nanowire radial junction includes the following steps:
[0022] First, a bottom electrode is fabricated on the detector substrate using sputtering or vacuum evaporation methods;
[0023] Then, perovskite core nanowires are fabricated on the detector substrate using a solution method, and then a first perovskite epitaxial shell and a second perovskite epitaxial shell are fabricated by solution epitaxy and doping to form a radial pin or pn junction;
[0024] Finally, a top electrode was deposited on the outer shell using a sputtering method.
[0025] Preferably, perovskite nanowires are grown using a solution method. A typical growth method involves first growing perovskite crystals, such as p-type MAPbBr3, using an anti-solvent method or a temperature inversion method. The perovskite crystals are then pulverized into powder and dissolved in a DSMO solution to obtain a perovskite nanowire precursor solution. An alumina template is prepared on the bottom electrode using anodizing. The prepared precursor solution is then dropped onto the alumina template and heated at 60°C for 8 hours in a vacuum furnace to evaporate all the solvent, resulting in a perovskite single-crystal nanowire array.
[0026] The beneficial effects of this invention are:
[0027] (1) The present invention proposes a photodetector based on a radial junction of perovskite nanowires. Since the effective area of the depletion layer formed by the radial junction is much larger than that of the depletion layer of the planar junction, the responsivity and quantum efficiency of the photodetector based on the radial junction of perovskite nanowires are higher than those of the planar junction detector.
[0028] (2) The present invention proposes a photodetector based on a radial junction of perovskite nanowires. Since the perovskite nanowire array has a certain light trapping effect, it reduces the reflectivity of incident light and further improves the photodetector efficiency.
[0029] (3) This invention proposes a photodetector based on a radial junction of perovskite nanowires. Compared with amorphous thin-film photodetectors, perovskite nanowires have a single-crystal or quasi-single-crystal structure in the radial direction, so the radial transport performance of photogenerated carriers is far superior to that of amorphous thin films. Therefore, recombination of photogenerated carriers can be reduced, further improving the quantum efficiency of photodetection. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the photodetector structure based on the radial junction of perovskite nanowires proposed in this invention.
[0031] Figure 2 Step 1 of the fabrication process for the photodetector based on a perovskite nanowire radial junction proposed in this invention: bottom electrode deposition;
[0032] Figure 3 Step 2 of the fabrication process for the photodetector based on the radial junction of perovskite nanowires proposed in this invention: p-type core nanowire growth;
[0033] Figure 4 Step 3 of the fabrication process for the photodetector based on a perovskite nanowire radial junction proposed in this invention: intrinsic epitaxial layer growth;
[0034] Figure 5 Step 4 of the fabrication process for the photodetector based on a perovskite nanowire radial junction proposed in this invention is: growth of an n-type epitaxial layer.
[0035] Figure 6 Step 5 of the fabrication process for the photodetector based on a perovskite nanowire radial junction proposed in this invention: top electrode deposition;
[0036] In the figure: 21-Transparent substrate, such as glass or plastic; 22-Bottom electrode; 23-P-type perovskite nanowire; 24-Perovskite intrinsic epitaxial layer; 25-Perovskite n-type epitaxial layer; 26-Top electrode. Detailed Implementation
[0037] The present invention will now be described in detail. This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.
[0038] like Figure 1 As shown, a photodetector based on a radial junction of perovskite nanowires includes a detector substrate 21, a bottom electrode 22, a perovskite core nanowire, a first epitaxial shell of perovskite, a second epitaxial shell of perovskite, and a top electrode.
[0039] The perovskite core nanowire is either a p-type perovskite nanowire or an n-type perovskite nanowire.
[0040] The first epitaxial shell of the perovskite is an intrinsic epitaxial layer 24 of perovskite, and the second epitaxial shell of the perovskite is an n-type epitaxial layer 25 of perovskite or a p-type epitaxial layer of perovskite.
[0041] The perovskite core nanowire, the first perovskite epitaxial shell, and the second perovskite epitaxial shell constitute a radial pin junction.
[0042] The bottom electrode 22 forms an ohmic contact with the perovskite core nanowire, and the top electrode 26 forms an ohmic contact with the second epitaxial shell of the perovskite.
[0043] The above-mentioned method for fabricating a photodetector based on a perovskite nanowire radial junction includes the following steps:
[0044] like Figure 2 As shown, a bottom electrode 22 is first deposited on a transparent substrate, such as glass or plastic, which serves as the detector substrate 21, using vacuum evaporation or sputtering. To achieve higher photodetection efficiency, this electrode can be a transparent electrode, such as ITO or FTO.
[0045] The second step involves growing p-type perovskite core nanowires 23 on the bottom electrode 22 using a solution method, such as... Figure 3 As shown. A typical growth method is to first grow p-type perovskite crystals, such as MAPbBr3, using methods such as anti-solvent or inverse temperature methods. Then, the perovskite crystals are pulverized into powder and dissolved in DSMO solution to obtain a perovskite nanowire precursor solution. An alumina template is prepared on the bottom electrode using anodizing. The aforementioned precursor solution is then dropped onto the alumina template, and the mixture is heated at 60°C for 8 hours in a vacuum furnace to evaporate all the solvent, resulting in a perovskite single-crystal nanowire array.
[0046] The third step involves epitaxially growing an intrinsic perovskite epitaxial layer 24 around the p-type perovskite core nanowire 23, such as... Figure 4 As shown. A typical intrinsic perovskite material is MAPbBr. 2.5 Cl 0.5 MAPbBr2.5 Cl 0.5 Precursor droplets are placed on a perovskite nanowire array, and an epitaxial layer is grown using a temperature inversion method. To ensure good lattice matching between the nanowires and the epitaxial layer, several buffer layers can be placed between them.
[0047] The fourth step involves epitaxially growing a perovskite n-type epitaxial layer 25 around the intrinsic perovskite epitaxial layer 24, as follows: Figure 5 As shown. Its epitaxial growth method is similar to step 3, and a typical n-type perovskite material is MAPbCl3.
[0048] Fifth step: Deposit the top electrode 26 on the perovskite n-type epitaxial layer 25, as follows... Figure 6 As shown. A typical deposition method is magnetron sputtering, where the top electrode needs to have good light transmittance, and can be ITO or FTO, etc.
[0049] The present invention can also set the perovskite core nanowire as n-type, and then sequentially epitaxially extend the intrinsic layer and p-type layer to form a nip radial junction.
[0050] The intrinsic layer can also be omitted in this invention, and an n-type layer or a p-type layer can be epitaxially grown around the perovskite core nanowire to form a pn or np radial junction.
[0051] This invention can also modify the p-type or n-type properties of perovskite by doping it with metal ions without controlling the halogen composition. For example, doping with Bi... 3+ Mn 2+ Cu 2+ Sb 3+ Mg 2+ Metal ions form a perovskite n-type layer; Ag doping + Cs + Li + In 3+ Ba 2+ Metal ions form a perovskite p-type layer.
[0052] like Figure 1 As shown, when photons are incident from the top or bottom, they are absorbed by the perovskite nanowires, forming photogenerated carriers. However, only the photogenerated carriers generated by the depletion layer of the radial junction formed between the epitaxial layers can be sufficiently separated to form a photocurrent. By designing the band structure, the voltage drop on the intrinsic layer can be increased, thereby extending the depletion layer to the entire intrinsic layer.
[0053] This invention proposes a photodetector based on a perovskite nanowire radial junction. Compared to amorphous film photodetectors fabricated on glass or plastic, the effective area of the depletion layer photoelectric effect formed by the radial junction is much larger than that of planar films. Therefore, the responsivity and quantum efficiency of the perovskite nanowire radial junction photodetector are higher than those of amorphous film detectors. Furthermore, the perovskite nanowire array has a certain optical trapping effect, which reduces the reflectivity of incident light, further improving the photodetection efficiency. Since the perovskite nanowires have a single-crystal or quasi-single-crystal structure in the radial direction, the radial transport performance of photogenerated carriers is far superior to that of amorphous thin films. Therefore, recombination of photogenerated carriers can be reduced, further improving the quantum efficiency of photodetection.
[0054] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. A photodetector based on a perovskite nanowire radial junction, characterized in that: It includes a detector substrate, a bottom electrode, a perovskite core nanowire, a first perovskite epitaxial shell, a second perovskite epitaxial shell, and a top electrode; The perovskite core nanowires are either p-type or n-type perovskite nanowires. The first epitaxial shell of the perovskite is an intrinsic epitaxial shell of perovskite, and the second epitaxial shell of the perovskite is an n-type epitaxial shell of perovskite or a p-type epitaxial shell of perovskite. Perovskite core nanowires are fabricated on a detector substrate using a solution method. Then, a first perovskite epitaxial shell and a second perovskite epitaxial shell are fabricated using solution epitaxy and doping methods. The perovskite core nanowires, the first perovskite epitaxial shell, and the second perovskite epitaxial shell constitute a radial pin junction. The perovskite core nanowires have a single-crystal or quasi-single-crystal structure in the radial direction; The bottom electrode forms an ohmic contact with the perovskite core nanowire, and the top electrode forms an ohmic contact with the perovskite second epitaxial shell.
2. A photodetector based on a perovskite nanowire radial junction according to claim 1, characterized in that: The first epitaxial shell of the perovskite is configured as an n-type layer or a p-type layer, which forms a pn junction with the perovskite core nanowire.
3. A photodetector based on a perovskite nanowire radial junction according to claim 1, characterized in that: The detector substrate is a transparent substrate, and the top and bottom electrodes are made of transparent electrode materials.
4. A photodetector based on a perovskite nanowire radial junction according to claim 1, characterized in that: The semiconductor properties of the perovskite core nanowires, the first perovskite epitaxial shell, and the second perovskite epitaxial shell are regulated by changing the elemental composition; the p-type perovskite is MAPbBr3, and the intrinsic perovskite is MAPbBr. 2.5 Cl 0.5 n-type perovskite is MAPbCl3.
5. A photodetector based on a perovskite nanowire radial junction according to claim 1, characterized in that: The perovskite core nanowires, the first perovskite epitaxial shell, and the second perovskite epitaxial shell are doped with Bi. 3+ Mn 2+ Cu 2+ Sb 3+ Mg 2+ Metal ions form perovskite n-type layers; Ag doping + Cs + Li + In 3+ Ba 2+ Metal ions form a perovskite p-type layer.
6. A photodetector based on a perovskite nanowire radial junction according to claim 1, characterized in that: Several buffer layers are inserted between the perovskite core nanowire, the first epitaxial shell of perovskite, the p-type layer of the second epitaxial shell of perovskite, the intrinsic layer and the n-type layer, so that the lattice constant mismatch rate on both sides of the interface is less than 3%.
7. A photodetector based on a perovskite nanowire radial junction according to claim 1, characterized in that: The photodetector omits the intrinsic perovskite epitaxial layer and directly grows an n-type layer around the p-type perovskite core nanowire, thereby forming a pn radial junction.
8. A photodetector based on a perovskite nanowire radial junction according to claim 1, characterized in that: The photodetector sets the perovskite core nanowires to n-type, and then grows intrinsic and p-type layers sequentially to form a nip radial junction or an np radial junction.
9. A method for fabricating a photodetector based on a perovskite nanowire radial junction according to any one of claims 1-8, characterized in that: Includes the following steps: First, a bottom electrode is fabricated on the detector substrate using sputtering or vacuum evaporation. Then, a perovskite core nanowire is fabricated on the detector substrate using a solution method. Next, a first perovskite epitaxial shell and a second perovskite epitaxial shell are fabricated using solution epitaxy and doping to form a radial pin or pn junction. Finally, a top electrode is deposited on the outer shell using sputtering.
10. A method for fabricating a photodetector based on a perovskite nanowire radial junction according to claim 9, characterized in that: The method for preparing perovskite core nanowires by solution method is as follows: First, perovskite crystals are grown using an antisolvent method or a reverse temperature method. Then, the perovskite crystals are pulverized into powder and dissolved in DSMO solution to obtain a perovskite nanowire precursor solution. An alumina template is prepared on the bottom electrode using an anodic oxidation method. The aforementioned precursor solution is dropped onto the alumina template and heated at 60°C for 8 hours in a vacuum furnace. After evaporating all the solvent, a perovskite single crystal nanowire array is obtained.