Temperature-dependent Magnetotransport Study of Si-doped <i>β</i> – Ga₂O₃ Films

Monoclinic β – Ga₂O₃ has generated significant excitement due to the wide bandgap, high electrical breakdown and high electron mobility at room temperature. In this work, we will discuss temperature-dependent magnetotransport study of homoepitaxial Si-doped β – Ga₂O₃ (010) films grown via metal-organic vapor-phase epitaxy (MOVPE). Temperature dependent Hall measurements were carried out using Van der Pauw configuration. Hall measurement at room temperature yielded a linear slope and a carrier density (n) of ~ 4 x 10¹⁷ cm^-3. A non-linear Hall resistance was however observed at 10 K < T < 150 K indicating the presence of multiple channel conduction. A transport model using two-channel conduction was used to fit the experimental magnetotransport data resulting in carrier densities, n₁, n₂ and the corresponding mobilities of µ₁, and µ₂ respectively. With decreasing temperature, n₁ showed a freeze-out behavior with an activation energy of ~ 15 meV, whereas n₂ remained nominally unchanged. By combining electrostatic gating using ion-gel as a gate-dielectric, detailed magnetotransport and transport modeling, we will discuss the origin of multiple carriers, defect-mobility relationship, and the relevant scattering mechanisms in MOVPE grown Si-doped β – Ga₂O₃.