Native defects in In xGa 1−xN alloys

Abstract

To elucidate the role of native defects in determining the electronic and optical properties of In 1 −x Ga x N, energetic particle irradiation (electrons, protons, and 4He +) has been used to intentionally introduce point defects into In x Ga 1 −x N alloys. Optical absorption, Hall effect, and capacitance–voltage (CV) measurements are used to evaluate properties of these materials. Irradiation produces donor-like defects in In x Ga 1 −x N with x>0.34, while acceptor-like defects form in Ga-rich In x Ga 1 −x N ( x<0.34). A sufficiently high irradiation dose pins the Fermi level at the Fermi level stabilization energy ( E FS), as predicted by the amphoteric defect model. Pinning of the Fermi level at this energy is also responsible for the surface electron accumulation effect in unirradiated In-rich In 1 −x Ga x N.