| In recent years,photodetector,as a kind of photoelectric device which can be used to obtain,record and analyze information,has attracted more and more attention.At present,most materials used to prepare photodetectors are n-type semiconductors.People study the changes of material conductivity before and after light to reflect the performance of photodetectors.However,this material has a high dark current,which can meet the requirements of high responsivity and low dark current photodetectors.Therefore,p-n junction photodetector has become a research hotspot.As one of the important parts of p-n junction photodetectors,it is still a great chal enge to study high-performance p-type photodetectors because of the large hole effective mass,poor stability and complex fabrication process of p-type semiconductor materials.Metal oxide semiconductors have attracted much attention for their excel ent photoelectric performance,high thermal stability and ease of manufacture,which makes them stand out in the research of p-type photodetectors.Among many p-type metal oxides,CuO is expected to be used to prepare high-performance p-type photodetectors due to its narrow band gap width,high intrinsic carrier concentration and high absorption coefficient.Moreover,we can optimize the quality and optical performance of the CuO film through doping,and adjust its band gap,which can effectively expand the response wavelength range of photodetectors.In this paper,CuO films with different Ni doping concentrations were prepared by sol-gel method.A photoconductive photodetector based on this film was prepared and the effect of Ni doping on the photodetector performance was analyzed.To solve the problem of high dark current in photoconductive photodetectors,we prepared CuO/MAPbI3heterojunction photodetectors,and studied the effect of heterojunction structure on the photodetector performance.The main research contents and innovations of this paper include the following:?1?The influence of Ni doping concentration on the crystallization quality and absorption coefficient of sol-gel prepared CuO films was studied under different doping concentrations?0%,20%,40%?.CuO films with Ni doping concentrations of 0%,20%and 40%(CuO,Cu0.8Ni0.2O,Cu0.6Ni0.4O)were prepared by sol-gel method.The crystal ization quality,elemental composition and surface morphology of the film were analyzed by X-ray diffraction,X-ray photoelectron spectroscopy and atomic force microscopy.Furthermore,the influence of Ni doping on CuO film absorption coefficient was further investigated by measuring the absorption spectra of the films.According to the experimental test results,the sol-gel method adopted in this paper can effectively doped the CuO film with Ni,and the atomic percentage of Cu and Ni in the doped film is almost consistent with the expected results.In addition,20%of Ni doping not only effectively improve the quality of the crystal ization of the film,reduced the defects and impurities on the surface of the film,and through the contrast before and after doping thin film absorption spectra,found that 20%of Ni doping can improve the absorption of thin film in the 400-780 nm band coefficient,for the subsequent preparation based on this kind of film is the high quality of near-infrared light electric detector made full preparation.?2?The CuO photodetector was prepared by sol-gel method,and the influence of Ni doping concentration on the performance of the photodetector was studied.In this paper,the prepared Cu1-x-x Nix O?x=0,0.2,0.4?films were used as the photosensitive layer of the photodetector to prepare the Cu1-x-x Nix O photodetectors.By changing the wavelength of incident light from 400 to 780 nm and the power of incident light from 1 mW/cm2 to 5 mW/cm2,the changes of the performance of Cu1-x-x Nix O photodetector with Ni doping concentration,incident light wavelength and incident light power were studied.Through analysis,it is found that the Cu1-x-x Nix O photodetectors all have good response to the 635 nm laser,among which the Cu0.8Ni0.2O photodetector has the highest photocurrent,responsivity and external quantum efficiency,which values are 6×10-7 A,26.46 A/W and 5176%respectively.Combined with the previous analysis on the crystal ization quality of Ni doped CuO films,it is proved that the performance of CuO photodetector can be improved by Ni doping.In addition,compared with undoped CuO films,the surface roughness of Cu0.8Ni0.2O films is lower,which makes the electric field generated by Cu0.8Ni0.2O photodetectors more uniform under the same external bias pressure,thus further improving the performance of the photodetectors.Due to the existence of impurity level in the doped Cu0.8Ni0.2O film,and the higher absorption coefficient of the Cu0.8Ni0.2O film near the 780 nm band,the detection wavelength range of the Cu0.8Ni0.2O photodetector is extended to the vicinity of 780 nm,realizing the effective detection of visible-near-infrared.?3?The photoelectric performance of CuO/MAPbI3 heterojunction photodetector was studied by using the structure of heterojunction photodetector.A heterojunction photodetector was prepared by combining CuO with MAPbI3films.By comparing the current and voltage curves of this photodetector with pure CuO and pure MAPbI3 photodetectors under different incident light,it is found that CuO/MAPbI3 heterojunction photodetectors can suppress the dark current from 10-9 A to 10-12 A,and the switching ratio can be increased to 3000.This is because the inhibitor has a built-in electric field,and the photodetector can generate a photoelectric response under light without applying applied bias,which effectively inhibits the dark current.This heterojunction photodetector not only effectively inhibits the dark current and greatly reduces the power consumption of the photodetector,but also lays a foundation for the subsequent synthesis of Cu0.8Ni0.2O film with MAPbI3 film and the large-scale preparation of higher performance photodetectors. |
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