Formation of a quasi-two-dimensional electron gas in GaN/Al_xGa_1-xN heterostructures with diffuse interfaces

A STEM study of the interface by mapping changes of the N K-edge, the integrated intensity of AlL_2,3-edge, and the intensity of the ADF signal showed that Al_xGa_1-xN/GaN interfaces can be up to 20 A wide. Thus, detailed calculations of the electronic energy levels and distribution of the Q2D electron gas were then carried out for undoped GaN/Al_xGa_1-xN heterostructures with graded interfaces for different compositions x. The results of the calculation show that the values calculated for the concentration of Q2DEG agree with the experimental data which indicates that the model applied correctly describes the formation of the Q2DEG for different compositions of the Al_xGa_1-xN layer and its dependence on the AlN thickness.