Abstract:
We report on a systematic investigation of temperature dependent current-voltage (I-V)
characteristics of Pd/ZnO Schottky barrier diodes in the 30-300 K temperature range. The
ideality factor was observed to decrease with increase in temperature, whilst the barrier
height increases with increase in temperature. The observed trend has been attributed to barrier
inhomogeneities, which results in a distribution of barrier heights at the interface. Using
the dependence of saturation current values on temperature, we have calculated the
Richardson constant (A*) which was investigated in the two distinct temperature regions:
140–200 K and 210–300 K and values 3 x10-12 of and 3x10-9 A cm-2 K-2 were obtained,
respectively. A mean barrier height of 0.97 eV was obtained in the 140-300 K temperature
range. Applying the barrier height inhomogeneities correction, the value of A* was obtained
from the modified Richardson plots as 39.43 and 39.03 A cm-2 K-2 in the 140-200 K and
210-300 K temperature range. The modified Richardson constant (A**) has proved to be
strongly affected by barrier inhomogeneities and dependent on contact quality.
