“…C-V method is an alternative characterization technique that has been used extensively on wide bandgap semiconductors such as GaN [17], SiC [18] and ZnO [19,20]. The Hg probe has been used as good Schottky contact even in the case of high carrier concentration up to 10 19 cm À3 [18,19]. The carrier concentrations (n) can be obtained by n ¼ 2=q ½dðÀ1=C 2 Þ=dV [21], where q is the electron charge, e is the relative dielectric constant with the value of 8.5 for ZnO material, C is the barrier capacitance per unit area, and V is the applied voltage, respectively.…”