Native defects in In_xGa_(1-x)N alloys

摘要

To elucidate the role of native defects in determining the electronic and optical properties of In_(1-x)Ga_xN, energetic particle irradiation (electrons, protons, and ~4He~+) has been used to intentionally introduce point defects into In_xGa_(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_xGa_(1-x)N with x > 0.34, while acceptor-like defects form in Ga-rich In_xGa_(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_xN.