Momentum matrix element and conduction band nonparabolicity in wurtzite GaN

Comparing the imaginary part of the dielectric function of wurtzite GaN measured by spectroscopic ellipsometry at room temperature with calculations, we found the values of Ep=(19.8±0.5)eV, m0*=(0.201±0.005)m0, and F=−0.89±0.05 for the momentum matrix element, electron effective mass at the conduction band edge, and parameter F describing the influence of remote bands, respectively. We also observed a remarkable nonparabolicity of the conduction band. The data obtained are consistent with A sets of valence band parameters reported earlier providing a parameterization of band structure of wurtzite GaN in the vicinity of the Γ point.