The author has investigated the effect of dislocations on thermoelectric properties of n- GaN based on two layer model and developed a model for calculation of the Seebeck coefficient, the thermal conductivity and the Figure of merit of n-GaN for the bulk n-GaN considering the two layer model. The effect of band quantization on the transport properties of n-GaN based on two layer model has been investigated. The variation of electronic conductivity with high magnetic field under the extreme quantum limit has been studied. The effect of dislocation in n-GaN on the Seebeck coefficient has been studied. Here the author has studied ac and dc mobility of hot electrons in the presence of a quantizing magnetic field where a small AC signal is superimposed on a DC electric field. It is applied to n-GaN in the low and high temperature regions. The author has studied the effect of dislocations and the non equilibrium phonons on the ac mobility of hot electrons at low and high temperatures. The author has studied the effect of various scattering mechanisms on the dc mobility and the effect of dislocations on transport peoperties of electrons in 2DEG in AlGaN/GaN .