Lattice Dynamics and Electron Transport in α-Ga₂O₃

Ga₂O₃ is an important wide bandgap material with applications ranging from power to RF electronics. It occurs in 5 polymorphs α, β, γ, δ and ε. β-Ga₂O₃ is extensively studied as it is thermodynamically a more stable phase & availability of bulk crystals. However, α-Ga₂O₃ has higher bandgap than β-phase, so better performance is expected for power applications. Although few reports exist on α-Ga₂O₃, it has not gained much traction as it is thermodynamically semi-stable making its synthesis challenging until recently where single crystalline α-Ga₂O₃ thin films were successfully grown. This opens a wide array of fields in device synthesis using α-phase (R3-c) which has a structure like corundum and thus can be potentially alloyed with materials like Cr₂O₃ and Fe₂O₃, with possibilities for magnetoelectric applications. We will present a detailed study of the lattice dynamics, electronic structure and low field electron transport properties in α-Ga₂O₃. Calculated Raman spectra is compared with experiments. The electron-phonon matrixelements are calculated under the DFT, DFPT and Wannier function formalism. We will also analyze the effects of temperature and doping on the mobility using the Boltzmann transport eqⁿ. Emphasis will be laid on identifying the dominant scattering mechanism.