Exploring the influence of Mott–Schottky acquisition parameters on the semiconduction behaviour of modified native aluminium oxide films

The Mott-Schottky approach was applied to access the semiconduction behaviour of native aluminium oxide films of pure aluminium (99.5 wt%) and Al-7075-T6 (Al-Zn-Mg-Cu) alloy investigating the effect of acquisition parameters and surface treatment. Pristine samples were subjected to Mott-Schottky cycling, showing higher defective donor states for Al-7075-T6. The application of step rates of 50–100 mV resulted in flat M−S plots, implicating the influence of the potential independent Helmholtz layer on the space charge capacitance. Chemical etching reduced the oxide thickness for both specimens, whereas higher defect donor densities were determined for pure Al.