Preparation And Optical Properties Of Low-dimensional Heterojunction Based On CsPbBr₃

The van der Waals heterostructures based on the vertical stacking of one-dimensional and two-dimensional materials based on the chemical vapor deposition method has attracted widespread attention,It is expected to open up a new era of electronics and optoelectronic devices.The two-dimensional materials have dangling-bond-free on the surface and will interact with different dimensional materials through vd W forces to be integrated mixed-dimensional vd W heterostructures,which will bring brand-new structures and properties.In recent years,the research of optoelectronic devices based on the wide spectrum coverage of low-dimensional semiconductor heterostructures and ultra-high sensitivity has aroused widespread interest from scientists at home and abroad.Previous research mainly focused on the controllable growth and properties of one-dimensional/one-dimensional or two-dimensional/two-dimensional heterojunctions.Since one-dimensional and two-dimensional materials have different properties,respectively,combining one-dimensional and two-dimensional materials to construct a one-dimensional/two-dimensional mixed-dimensional heterojunction will provide new material options for next-generation optoelectronic devices.At the same time,research on one-dimensional/two-dimensional heterojunctions may pave the way for the development of surface integrated devices.In this paper,the optical properties of low-dimensional semiconductor heterostructures are studied on the basis of high-quality mixed-dimensional heterostructures synthesized by vapor deposition method.The first part of the paper is mainly a literature review of one-dimensional,two-dimensional and one-dimensional/two-dimensional mixed-dimensional semiconductor heterojunctions.At the same time,we discusses and analyzes the preparation methods and application directions of different heterojunctions;The second part studies the preparation,morphological characterization and optical properties of the mixed-dimensional one-dimensional PbBr₂/two-dimensional MoS₂ heterojunction;The third part focuses on the preparation of SnSe/CsPbBr₃ heterojunction and its photoelectric properties;The fourth part is the study of the preparation and optical properties of CsPbBr₃/MoS₂heterojunction.The specific research content is as follows:(1)Combining chemical vapor deposition and physical vapor deposition methods,the controlled growth of heterojunctions of one-dimensional PbBr₂ nanowires/two-dimensional MoS₂ monolayer nanosheets was successfully realized.Optical photos show that one-dimensional PbBr₂ nanowires can nucleate and grow epitaxially on top of two-dimensional MoS₂ single-layer nanosheets,and their growth direction has a certain randomness.(2)The morphology and thickness of the obtained heterostructure were characterized by scanning electron microscope and atomic force microscope.Through steady-state photoluminescence spectroscopy and time-resolved photoluminescence spectroscopy,the optical properties of the heterojunction were studied,and it was confirmed that there is an obvious charge transfer behavior between the top PbBr₂nanowires and the bottom monolayer MoS₂ nanosheets.Through time-resolved photoluminescence spectroscopy,the interlayer coupling and photoinduced interface charge behavior of the prepared one-dimensional PbBr₂/two-dimensional MoS₂heterostructure were studied.The charge transfer efficiency was calculated to be about40.6±0.2%.The one-dimensional PbBr₂/two-dimensional MoS₂ heterostructure with high-efficiency charge transfer may become a candidate material for the next generation of optoelectronic devices.(3)SnSe nanosheets were prepared on mica sheets by physical vapor deposition method.Through atomic force microscopy,the thickness of SnSe was found to be 1.3?m,and the phonon vibration mode of SnSe was analyzed by Raman.Furthermore,CsPbBr₃ perovskite nanosheets were epitaxially grown on SnSe by chemical vapor deposition to obtain CsPbBr₃/SnSe heterojunction.The X-ray photoelectron spectroscopy test results confirmed the element composition in the heterojunction and proved the successful preparation of the SnSe/CsPbBr₃ heterojunction.(4)The CsPbBr₃/MoS₂ heterojunction was prepared by a two-step chemical vapor deposition method,the element composition of the heterojunction was analyzed by EDS energy spectrum,and the optical properties of the heterojunction were studied by PL spectroscopy,and CsPbBr₃/MoS₂ was found The luminous intensity of CsPbBr₃nanosheets with different contrast colors in the heterojunction is different.Further data analysis found that the shift range of the CsPbBr₃ nanosheets of different colors relative to the PL peak of the heterojunction is 4.5 nm.