Theoretical Study of Orientation Dependence of Piezoelectric Effects in Wurtzite Strained GaInN/GaN Heterostructures and Quantum Wells

We calculated the crystal orientation dependence of piezoelectric fields in wurtzite strained Ga 0.9 In 0.1 N/GaN heterostructures. The highest longitudinal piezoelectric field of 0.7 MV/cm can be generated in (0001)-oriented biaxial-strained Ga 0.9 In 0.1 N layer coherently grown on GaN. On the contrary, no longitudinal piezoelectric field is induced in strained layers grown along orientations at an off angle of 39° or 90° from (0001). The high symmetry planes with these angles are, for instance, (1124) and (1012) for 39°, and (1120) and (1010) for 90°. We also calculated the crystal orientation dependence of the transition probability in a 3-nm strained Ga 0.9 In 0.1 N/GaN quantum well, which indicated that the transition probability with these non-(0001) orientations becomes 2.3 times larger than that with the (0001) orientation. We conclude that high-performance strained nitride-based optical devices can be obtained by control of the crystal orientation.