Low field electron transport in α - 2 O 3: An ab initio approach

Trigonal α - G a 2 O 3 is an ultrawideband semiconductor with potential applications in power electronics and ultraviolet opto-electronic devices. In this Letter, we calculate the low field electron mobility in α - G a 2 O 3 from first principles calculations. The effect of all the 30 phonon modes is taken into account for the transport calculation. The phonon dispersion and the Raman and Infrared spectra are calculated under the density functional perturbation theory formalism and compared with experiments. The electron-phonon interaction (EPI) elements on a dense reciprocal space grid are obtained using the Wannier function interpolation. The full energy dispersion of the phonons is included in both the polar and nonpolar EPI calculations. The electron mobility is then evaluated incorporating the effects of the polar, nonpolar, and ionized impurity scattering using Rode's iterative method. At room temperature, the low field isotropic average electron mobility is estimated to be ∼220 c m 2 / V s predominantly limited by the polar optical phonon scattering at a doping density of 1.0 × 1 0 15 c m - 3. The anisotropy in the mobility arising from the phonon scattering is also evaluated. Temperature and dopant concentration variation of mobility is also studied, which can help in optimization of the growth for transport measurements.