Piezoelectric effect on Al0.35−δInδGa0.65N/GaN heterostructures

Al0.35−δInδGa0.65N/GaN heterostructures have been studied by using transmission electron microscopy, photoluminescence, and Shubnikov–de Haas (SdH) measurements. In the sample of δ<0.01%, two SdH oscillations beat each other due to the population of the lowest two subbands. The carrier concentrations of these two subbands are 1.398 and 1.248×1013 cm−2 and the electric field at the interface is reduced to 2.19×104 V/cm, which is one order of magnitude smaller than that of Al0.35Ga0.65N/GaN heterostructure. We suggest that a small fraction of In atoms in the Al0.35−δInδGa0.65N can be used as a tuning parameter to control the strain and the piezoelectric field at the interface.