Transport characteristics of Pd Schottky barrier diodes on epitaxial n-GaSb as determined from temperature dependent current-voltage measurements

The temperature dependent transport characteristics of Pd/n-GaSb:Te Schottky contacts with low and saturating reverse current are investigated by means of current-voltage measurements between 80 K and 320 K. The apparent barrier height and ideality factor increase with a decrease in temperature. Neither thermionic nor thermionic field emission can explain the low temperature characteristics of these diodes. Instead, evidence is presented for barrier inhomogeneity across the metal/semiconductor contact. A plot of the barrier height, ϕb vs. 1/2kT revealed a double Gaussian distribution for the barrier height with ϕb,mean assuming values of 0.59 eV ± 0.07 (80-140 K) and 0.25 eV ± 0.12 (140-320 K) respectively.