High-density InGaN nanodots grown on pretreated GaN surfaces

Abstract

High-density InGaN nanodots are successfully grown on pretreated GaN surfaces. The GaN surfaces were covered by SiO2 layers firstly, and then the SiO2 layers were removed before the growth of InGaN on the GaN. After this process, the growth of InGaN on the GaN surfaces changed to a three-dimensional mode. However, on the GaN surface without the SiO2 treatment, the growth of InGaN maintained a two-dimensional growth mode as usual. The InGaN nanodots are 26to68nm in diameter, 3.6–15nm in height, and up to 9×1010cm−2 in density, which can be controlled by growth duration and substrate temperature. Comparing with the InGaN thin film grown on untreated GaN surface with the same growth conditions, the InGaN nanodots showed stronger photoluminescence in longer wavelength range at room temperature. The formation mechanism of the nanodots is described based on the GaN surface states changed by SiO2 coverage. This approach enables fabrication of dense and controllable InGaN nanodots.