Shallow impurity states in wurtzite and zincblende structure GaN

Calculations of shallow donor states for wurtzite and zincblende structure GaN, and acceptor states for zincblende GaN in an effective mass approximation are presented. Band parameters were taken from experiment or determined from band structure calculations. The effect of wavevector dependent screening is examined, based on dielectric functions calculated from empirical pseudopotential band structures. For donor states, the effects of electron-phonon coupling and free carrier screening in the Thomas-Fermi and Debye approximations are discussed briefly.