Two-Step Growth of Gan Quantum Dots with Metalorganic Chemical Vapor Deposition

Abstract

ABSTRACTNanometer-scale GaN dots were successfully fabricated on sapphire using metalorganic chemical vapor deposition(MOCVD) by two-step method, including depositing around 500 IC and annealing at 1050 °C. The density of GaN dots is from 5×108cm−2 to 6×109 cm−2, and the size is around 40nm in diameter. The density and size of GaN dots are determined by an atomic force microscope(AFM), and they are controllable by changing temperature and duration of the growing. GaN dots only formed after annealing at high temperature, which is explained that the initial layer deposited around 500 °C is a high energy intermediate phase in which the large strain energy can not be relaxed because of the low temperature growing.