In‐plane polarization of GaN‐based heterostructures with arbitrary crystal orientation

The total polarization fields of pseudomorphic InxGa1−xN/GaN and AlxGa1−xN/GaN heterostructures with 0 ≤ x ≤ 0.4 have been calculated as a function of the crystal orientation. Especial attention is placed on the direction and magnitude of in‐plane piezoelectric polarization, which is not negligible for the non‐polar and semi‐polar growth. For an arbitrary crystal orientation, the piezoelectric polarization prevails in the InGaN/GaN system while the spontaneous polarization prevails in the AlGaN/GaN system. The in‐plane potential due to polarization fields in non‐polar epilayers is found to depend on the degree of planarity of the heterojunctions, and on the respective lateral dimensions.