Investigation of the effect polarization on the electronic properties of heterostructures by the monte carlo method

In nitride containing single or multi-junction structures, polarization fields (both spontaneus and piezoelectric) lead to high electron charge concentrations. In some cases, it is possible to obtain very high free electron concentrations (1012?1013 cm-2) as a result of energy band bendings that took place due to polarization effects, even in the absence of any intentional doping. In this thesis, for a modulation doped AlGaN/GaN structure the Poisson/Schr¨odinger equations are solved self consistently. The effect of the thickness of the doped region, doping concentration, the dimensions of the heterostructure and especially spantoneous and piezoelectrik polarizations on the electronic properties of this structure are investigated. Next, the electron concentration that forms at the interface due to spantouneous and piezoelectric effects in the absence of any doping is investigated.The exchange-correlation effects are also taken into account for both cases. The potential profile that forms at the junction, empty and filled energy levels and their corresponding wave functions, the elcetron concentration at each level are found. Using the wave functions and the energy levels obtained from the self consistent solutions, the two dimensional scattering (surface roughness, acoustic phonon and polar optic phonon) rates are calculated. Using these scattering rates electron transport properties of the structure are investigated by ensemble Monte Carlo method. Similar calculations are also carried out for a quantum well structure.