Low field electron mobility in GaN

Temperature and doping dependencies of electron mobility in GaN have been calculated using an iterative technique. The following scattering mechanisms, i.e., impurity, polar optical phonon, acoustic phonon, piezoelectric, and electron plasmon are included in the calculation. Ionized impurity scattering has been treated beyond the Born approximation using a phase-shift analysis. The compensation ratio is used as a parameter with a realistic charge neutrality condition. Comparisons with experimental data confirm the present calculation over a wide range of temperatures and electron concentrations. Mobility and electron concentration data from Hall measurements reveal a degenerate layer at the GaN-substrate interface. This degenerate layer affects the bulk mobility and electron concentration and needs to be accounted for in order to extract reliable experimental values of the bulk electron mobility. (C) 1999 American Institute of Physics. [S0021-8979(99)00217-0].