Formation characteristics of a self-catalyzed GaAs nanowire without a Ga droplet on Si(111)

Ga droplets were totally removed from the top region of self-catalyzed GaAs nanowires (NWs) formed on Si(111), which was done by controlling the arsenic conditions during the growth period and the cooling process of the substrate temperature. From the spatial luminescence profiles of the GaAs NWs measured by using laser confocal scanning microscopy, the emission position from the NWs without Ga droplets was 896. 4 nm. This was shorter than that with the Ga feature (912. 7 nm). The difference in the emission wavelengths can be explained by the scattering probability of the photons from GaAs NWs in Ga droplets and by a modification in the energy level caused by the interface condition.