Room-temperature diffusive phenomena in semiconductors: The case of AlGaN

Diffusion mediated by native point defects does not generally occur in semiconductors at room temperature (RT) because of high activation energies. However, recently observed plastic deformation in AlGaN/GaN structures in the presence of strain and electric fields was attributed to diffusive processes. Here, we report first-principles calculations showing that strain has little effect, but RT mass transport is enabled by near-zero formation energy of triply negative cation vacancies and a concomitant electric-field-induced lowering of migration energy. Similar phenomena are predicted to occur in other large-gap materials.