Diffusion Thermopower In GaN/AlGaN Heterostructures

We present a study of diffusion thermopower in two dimensional electron gas in GaN/AlGaN heterostructures at low temperatures. We have considered important conventional scattering mechanisms such as surface roughness, dislocations via coulomb field and in addition new scattering mechanisms arising due to roughness viz, misfit piezoelectric and misfit deformation potential scattering. The diffusion thermopower of each of the mechanisms are calculated separately and also combined as a function of electron concentration, temperature, dislocation density and correlation length. The study shows new roughness induced scattering mechanisms are very important and dominant besides the other conventional scattering mechanisms.