Study of Anisotropic Strain in Self-Assembled GaN Microdisks Grown by Molecular Beam Epitaxy

Systematic research has been done on lattice relaxation on wurtzite GaN microdisks produced by plasma-assisted molecular beam epitaxy. High-resolution transmission electron microscopy was used to assess the lattice constants of GaN microdisks. The anisotropic strain was analyzed by the microscopic atomic layers of GaN microdisks. We learned that the lateral lattice strain along a-axis followed a linear relation during the epi-growth, while the vertical lattice strain with c-axis exhibited a quadratic deviation.