Electrical conductivity and lattice expansion of β-Ga2O3 below room temperature

The temperature dependence of the electrical properties of β-Ga2O3 is analyzed from liquid helium to room temperature by Hall measurements. Below 100K, the carrier motion takes place within the impurity conduction band and it shows a power-law dependence. An electrostructural coupling is ascertained. Thermal activation in the conduction band is observed above 100K, with an activation energy Ea=7meV. Thermal conductivity is measured to 13Wm−1K−1. Further, it is shown that Ti is a good Ohmic electrode for n-type β-Ga2O3 substrates.