Fig. 1. (Color online) I–V curves for as-prepared and 400 °C annealed samples. The insert is the schematic structure of the Mg/Au/β-Ga₂O₃ contact.

Fig. 2. (Color online) (a) Resistance of Mg/Au-β-Ga₂O₃ structure with two adjacent ohmic contacts versus the distance at different temperatures. (b) Contact resistance and sheet resistance of the ohmic contact Mg/Au-β-Ga₂O₃ versus measuring temperatures.

Fig. 3. (Color online) Specific contact resistance of the ohmic contact Mg/Au-β-Ga₂O₃ versus measuring temperatures.

Fig. 4. (Color online) The dependence of ln (ρ_cT) on 1/T graph about Mg/Au-β-Ga₂O₃ ohmic contact for the annealed sample, experimental data (point) and TE model fitting (line).