A numerical study of amplification of space charge waves in n-GaN films

A Numerical study of amplification of space charge waves (SCW) due to the negative differential conductivity in n-GaN films placed onto a semi-infinite substrate is investigated. A case of transverse non-uniform film is considered. The set of balance equations for concentration, drift velocity, and the averaged energy to describe the dynamics of space charge waves were used jointly with the Poisson equation for the electric field. It is possible to observe an amplification of SCW in n-GaN films of submicron thicknesses at essentially higher frequencies f >;100 GHz, when compared with n-GaAs. Two-dimensional simulation of spatial distribution of the alternative part of the electric field of space charge wave in 2D is presented.