Abstract:
We report on the analysis of current voltage (I-V) measurements performed on Pd/ZnO
Schottky barrier diodes (SBDs) in the 80-320 K temperature range. Assuming thermionic
emission (TE) theory, the forward bias I-V characteristics were analysed to extract Pd/ZnO
Schottky diode parameters. Comparing Cheung’s method in the extraction of the series
resistance with Ohm’s law, it was observed that at lower temperatures (T<180 K) the series
resistance decreased with increasing temperature, the absolute minimum was reached near
180 K and increases linearly with temperature at high temperatures (T>200 K). The barrier
height and the ideality factor decreased and increased, respectively, with decrease in
temperature, attributed to the existence of barrier height inhomogeneity. Such inhomogeneity
was explained based on TE with the assumption of Gaussian distribution of barrier heights
with a mean barrier height of 0.99 eV and a standard deviation of 0.02 eV. A mean barrier
height of 0.11 eV and Richardson constant value of 37 A cm-2 K-2 were determined from the
modified Richardson plot that considers the Gaussian distribution of barrier heights.
