Preparation And Performance Study Of ZnO/Bi₂Te₃ Heterojunction

With the continuous development of the technological society,people's demand for photoelectric detectors has gradually increased.In order to meet the characteristics of high effect rate,fast response speed,integration and low cost,many new types of detectors such as quantum dot photodetectors,organic photodetectors and two-dimensional material detectors have emerged.In the device,the wide-spectrum detector can span multiple optical bands and can also cooperate with the filter to detect the narrow-band spectrum,so it can meet people's current pursuit of detector performance conditions to a large extent.Bismuth telluride(Bi₂Te₃)is a narrow band gap(0.15 ev-0.3 e V)topological insulator with high carrier mobility and high stability.It has shown an attractive prospect in the direction of wide-spectrum detection,in order to further improve Bi₂Te₃ is used as a photoanode material to prepare the device performance.In this paper,Bi₂Te₃ is combined with ZnO to prepare a heterojunction detector with a type II band structure based on this.The specific research content is as follows:First,the hexagonal Bi₂Te₃ nanosheets were prepared by hydrothermal method,and the shape of the sample was measured by scanning electron microscope(SEM),EDS spectrometer,X-ray photoelectron spectrometer(XPS)and X-ray diffractometer(XRD).Characterization and analysis of morphology,element composition and crystal structure.The effects of the content of polyvinylpyrrolidone(PVP),the content of Na OH,the molar mass ratio of Te and Bi atoms,and the temperature on the morphology and structural composition of Bi₂Te₃ nanosheets were explored.Growth mechanism.Secondly,one-dimensional ZnO nanorods were prepared by magnetron sputtering and hydrothermal methods,and then ZnO/Bi₂Te₃ heterojunctions were prepared by physical spin coating and heat treatment.The heterojunctions were characterized by SEM,EDS,XPS and XRD.The morphology and structural composition of the mass junction.The ZnO nanorods and ZnO/Bi₂Te₃ heterojunction were tested with an ultraviolet-visible spectrophotometer,and the results showed that the absorption spectrum of the ZnO/Bi₂Te₃ heterojunction had a red shift compared with the absorption spectrum of Bi₂Te₃ nanosheets.Finally,the Bi₂Te₃ nanoplate photodetector and the ZnO/Bi₂Te₃ heterojunction photodetector were prepared,and the detection performance of the two was tested.The results show that the Bi₂Te₃ nanosheet detector can detect ultraviolet light to visible light.Detection of near-infrared light.The device after being composited with ZnO nanorods has a higher photoresponse current and a faster corresponding speed,which is most obvious under the simulated light source of ultraviolet light.In addition,the detection mechanism was also studied and analyzed,and the results showed that the complex morphology formed by the composite of ZnO nanorods and Bi₂Te₃ nanosheets and the type II band structure constructed by the two are the main reasons for the performance improvement.