Piezoelectric properties of substitutionally doped β-Ga2O3

Modern semiconductor materials are increasingly used in multidisciplinary systems demonstrating cross-interactions between mechanical strains and electronic potentials, which gives rise to ubiquitous applications in high sensitivity, self-powered sensor devices. One of the fundamental prerequisites for such semiconductor materials to exhibit piezoelectric properties is the noncentrosymmetry of the crystal structures. β-Ga2O3 has been an emerging compound semiconductor material due to its ultra-wide bandgap. However, pristine β-Ga2O3 has an inversion center, displaying no piezoelectric effect. This work discovered that substitutionally doped β-Ga2O3 possesses piezoelectric property by using the first principles method, while a majority of previous research on its substitutional doping has been focused on the purposes of increasing electrical conductivity and formation of semiconductor heterojunctions. More interestingly, it is unveiled from this work that the formation energy has a clear relation with the piezoelectric coefficient.