By using low-field electrical transport simulations, it was shown that a mobility collapse at low dopant densities could not be interpreted simply in terms of dislocation scattering or trapping mechanisms. Instead, it was also controlled by the collective effect of dislocation walls (columnar structure). As the free-carrier density increased, a more efficient screening resulted in a transition from a barrier-controlled mobility regime to a purely diffusion-controlled mobility regime. It was possible to reproduce quantitatively the experimental mobility collapse.

Theoretical Simulation of Free Carrier Mobility Collapse in GaN in Terms of Dislocation Walls. J.L.Farvacque, Z.Bougrioua, I.Moerman: Journal of Physics - Condensed Matter, 2000, 12[49], 10213-21