Elasticity and inelasticity of bulk GaN crystals

The elastic and microplastic properties of large quasi-bulk GaN samples of two types, grown by hydride vapor-phase epitaxy, have been acoustically investigated. Samples of the first type are polycrystals textured along a crystallographic direction, while second-type samples are single crystals with characteristic V-shaped defects. The results are compared with the data in the literature and analyzed based on the existing theoretical concepts of the influence of dislocations and grain boundaries on the acoustic and mechanical properties of crystals.