Difficulty of long-standing n-type conductivity in equilibrium and non-equilibrium γ-CuCl: A first-principles study

Doping asymmetry is a pervasive issue in wide band gap semiconductors. We demonstrated that gamma-CuCl is one of them with an intrinsic p-type semiconductor by first-principles calculations. The valence band maximum of gamma-CuCl is dominated by the antibonding state of Cu-3d and Cl-3p, resulting in a high energy position. We further find that Cu vacancy has a relatively low diffusion barrier in addition to its low formation energy, implying that the long-standing n-type conductivity is hard to realize in gamma-CuCl even with non-equilibrium approaches. (C) 2017 Published by Elsevier B.V.