Extracting the Richardson constant: IrOx/n-ZnO Schottky diodes

A method is proposed to account for the effects of Schottky barrier height inhomogeneities on the Richardson constant (A∗) extracted from current-voltage-temperature (I-V-T) measurements. Our approach exploits a correlation between the extracted Richardson constant and effective barrier height. As a test case, the method is applied to I-V-T measurements performed on IrOx/n-ZnO Schottky diodes. A homogeneous A∗ value of 27±7 A cm−2 K−2 is obtained, in close agreement with the theoretically expected value of 32 A cm−2 K−2 for n-type ZnO.