Assessment of phonon scattering-related mobility in β-Ga₂O₃

The momentum scattering time for electron-phonon interaction in β-Ga₂O₃ was derived within the relaxation time approximation considering all infra-red active optical modes. A first principle calculation was applied to separately obtain the scattering rates due to polar and non-polar phonon-electron interactions, and then spherically averaged coupling coefficients for each polar optical mode were calculated. The method was tested to analyze, in the framework of the relaxation time approximation, transport data in semiconductors having different optical phonons. This approach can be reliably applied if the band may be considered as isotropic. Hall density and mobility curves were fitted simultaneously with the same parameters, after Hall-to-drift data conversion through a Hall scattering factor calculated self-consistently within the routine. In the theoretical mobility calculations, both polar and non-polar phonon interactions were considered besides impurity scattering. The Farvacque correction was included in the momentum scattering rate for electron interaction with the optical phonons, and its effect on mobility calculation is critically discussed. Hall transport data of β-Ga₂O₃ taken from the literature were fitted to test the approach, and good agreement between the experimental and calculated mobilities was obtained.