Controllable Growth And Characterization Of Low-Dimensional InGaAs Nanostructures

One-dimension(1-D)nanowire is one of the fundamental materials in nanodevices.Due to the high luminous efficiency and high carrier mobility,III-V nanowires,such as InAs and GaAs nanowires,are promising materials to fabricate nano-optoelectronics,electronics and novel quantum devices.A large-scale and controllable nanowires preparation method is the precondition for nanowires application.However,there still are three crucial problems for nanowires need to be solved: 1.Metal contaminants caused by metal catalyst,2.Stacking faults along nanowires,3.Transfer and localization of nanowires.This paper aims to grow lateral in-plane In(Ga)As nanowires by molecular beam epitaxy(MBE)without any metal catalyst,and realize the selected area growth of nanowires and quantum dots(QDs),which providing a nanoscale building block for the integrated circuits application.The details are as follows:1.Demonstrate a new method to lateral growth in-plane InAs nanowires on GaAs(001)by MBE.The nanowires were induced by the oxygen plasma irradiation without any metal catalyst.To avoid the degradation of oxygen plasma effect during the high growth temperature,GaAs deoxidization and low temperature GaAs buffer layer growth conditions were studied respectively.Then,triple layers nanowires with stacking structure are achieved which shown strong emission by photoluminescence(PL)characterization.Besides,by using this method we demonstrated the plasma induce lateral growth in plane InAsSb nanowires grown on GaAs(001)substrate.2.Realize controllable growth of lateral InGaAs-AlAs core-shell nanowires on nano-ridges by using patterned GaAs(001)substrate.The nanowires diameters can be tuned according to control the growth temperature and thickness of GaAs buffer layer.Transmission electron microscope(TEM)images and low temperature PL results shown good crystal quality and optical property of the nanowires.3.Realize the InAs QDs localized growth within nano trenches and investigate a relationship between InAs QDs priority nucleation positions and angles of inclination in nano-trenches.With a small inclination angle,the InAs QDs preferentially nucleate inside the trenches.While with a large inclination angle,the edges of the trenches appear to be more preferred nucleation sites of InAs QDs.By utilizing the method,varies of InAs QDs localized patterns were achieved such as double dots,quadruple dots and dots chain.The site controllable growth of metal-catalyst-free lateral InGaAs nanowires without is realized in this paper,which plays a significant role in promoting nanowires devices integration and application.