Modulation of anisotropic crystalline in a-plane GaN on HT-AlN buffer layer

► a-Plane GaN was investigated in its strains and crystalline quality. ► Crystalline anisotropy can be improved using HT-AlN buffer. ► Strain transforms along [0 0 0 2] from compression to tensile using HT-AlN buffer. ► The contraction of lattice along [101¯0] induces the transformation of compression into tensile along [0 0 0 2].