Very high quality p-type AlxGa1-xN/GaN superlattice

Very high quality p-type AlGaN/GaN superlattices have been achieved through optimization of Mg flow and period of superlattice. A theoretical model was used to predict the performance of superlattice with different Al compositions and various periods. The model has based on polarization charge induced by spontaneous polarization and piezoelectric effect (due to lattice mismatch and thermal strain) which leads to enhancement in acceptor ionization and therefore carrier concentration. Piezoelectric coefficients for GaN system are about one order of magnitude larger than other group III-V semiconductors leading to a huge electric field