Characterizations of gallium arsenide nanowires grown by buffer layer assisted magnetron sputtering technique

Abstract

Semiconductor nanowires (NWs) are among the most extensively studied nanostructure for their potential applications in nanoscale devices. Gallium arsenide (GaAs) NWs is a high-performance material with direct bandgap and high electron mobility. Despite the great potential for future nanotechnology, its widespread use when integrated with silicon (Si) has been limited by lattice mismatch, difference in thermal expansion coefficient, antiphase boundaries, relatively high production cost and inadequate ecological safety. Here, the results of growing GaAs NWs onto Si substrate via radio frequency (RF) magnetron sputtering by using a simple single buffer layer are reported. This research presents the integration of GaAs NWs on Si with various thickness of sputtered GaAs buffer layer ranging from 10 nm to 110 nm using aurum (Au) nanoparticles as a seeding catalyst via vapour-liquid-solid mechanism. The desired morphology and uniform thickness of GaAs buffer layer with Au nanoparticles were annealed at Au-GaAs eutectic temperature in order to form an eutectic liquid alloy, followed by growth process between 570 ?C and 690 ?C growth temperature. The structural and optical properties of GaAs NWs were characterized using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy as well as photoluminescence, X-ray diffraction and ultraviolet-visible spectrophotometers. The results have shown that the sufficient thickness of buffer layer of about 19.48 nm, optimized annealing temperature at 630 ᵒC and a suitable growth temperature at 630 ᵒC play important roles in producing high quality buffer layer which then lead to growth of GaAs NWs.