Si Nanowire Gas - Liquid - Solid Controlled Growth And Doping Characteristics,

Silicon nanowires(SiNWs) are typical quasi-one-dimensional nanostructures, which have many novel physical properties and potential applications in nano-devices.They are synthesized on n-Si(111)substrates using Au film as catalyst and SiH4 gas as a vapor phase reactant based on vapor-liquid-solid mechanism by low pressure chemical phase deposition (LPCVD).The samples are characterized by scanning electron microscopy(SEM),energy-dispersive x-ray spectrometry(EDS) and X-ray powder diffraction(XRD).The effects of the growth temperature, SiH4 flow rate,thickness of Au film and growth time on the formation and structures of Si nanowires were discussed.High quality SiNWs can be well prepared in the growth conditions:the thickness of Au film is between 10-20 nm, the temperature is 650℃, the growth is 90min, and the flow of SiH4 is 40sccm, which diameters and lengths are 20-200nm and from several micrometers to sereral tens of micrometers.The PL spectrum shows that the SiNWs exhibited a strongly blue luminescent band in the wavelength range 400-480nm.Doping of SiNWs is achieved by post-diffusion and in situ-diffusion methods. The effects of B2H6 flow rate, doping time and temperature on sheet resistance are studied.The SiNW(p)/c-Si(n)heterostructure is prepared and current-voltage characteristic is measured.