Study On The Photoelectric Characteristics Of GaAs/GaAsSb Core-shell Nanostructures

Semiconductor devices,as an important component in the field of optoelectronics,have become an inseparable part of people's production and life at the present stage,with prominent advantages in national defense,optical fiber communications,gas sensing,pollution monitoring and other aspects.In order to further improve the performance of semiconductor optoelectronic devices,materials need higher electron mobility and photoelectric conversion efficiency.As an important semiconductor material in the nearinfrared band,antimony alloy has an important application prospect in the fields of infrared guidance,ocean monitoring and deep space exploration.The ternary alloy GaAsSb material has attracted much attention because its luminous wavelength can be flexibly adjusted in the wavelength range of 870 nm(GaAs)? 1 700 nm(Ga Sb)by regulating the Sb component.In terms of structure,the unique one-dimensional geometric structure of nanowires enables it to combine different materials to form core-shell structure,quantum well,axial heterojunction and other nanocomposite structures,which are the basic components for the development of modern semiconductor materials industry and also the core components of optoelectronic devices.The core-shell structure,which restricts the carrier in the radial direction to enhance the exciton binding efficiency and the band gap is flexible and adjustable,is expected to improve the energy efficiency,modulation speed and stability of optoelectronic devices.In this paper,molecular beam epitaxy(MBE)technology was used to prepare GaAs/GaAsSb core-shell structure nanowires and to study their photoelectric characteristics.The main research contents include the following:(1)Analyze the epitaxial growth mechanism of nanowires and thin films,and combine Vapor-Liquid-Solid and Vapor-Solid mechanism to build a theoretical model of GaAs/GaAsSb/GaAs core-shell nanowires.At the same time,the nucleation theory of epitaxial growth is clarified and the molecular dynamics of epitaxial growth is analyzed.The transition from Vapor-Liquid-Solid mechanism to Vapor-Solid mechanism is achieved by using the method of interrupt beam source,thereby achieving the coating of the shell.(2)The designed GaAs/GaAsSb/GaAs core-shell nanowire structure was subjected to epitaxial growth of the basic materials using MBE technology,including the epitaxial growth of GaAs,GaAsSb nanowires and GaAsSb thin films,and the epitaxial growth parameters were optimized to obtain high crystalline quality semiconductor materials.Its morphology,structure and luminescence properties were studied.(3)The GaAs/GaAsSb/GaAs core-shell nanowires were epitaxy grown using MBE technology.The morphology and structure of core-shell nanowires were studied.The results showed that the nanowires had good crystallization quality and uniform morphology.According to the study on its luminescence characteristics,under room temperature,the photoluminescence spectrum(PL)shows that the luminescence wavelength is about 1.2 ?m,and the flexible tuning of emission wavelength can be realized by adjusting the Sb component.In addition,the electrical properties of core-shell nanowires were studied,and the I-V test showed that the prepared GaAs/GaAsSb/GaAs nanowires had higher current strength compared with GaAs nanowires.In this study,epitaxial growth of GaAs/GaAsSb/GaAs coreshell nanowires of 1.2 ?m wavelength luminescent wavelength was realized,which laid a material foundation for the preparation of antimony-based semiconductor luminescent devices.