Current–voltage–temperature (I–V–T) characteristics of Pd/Au Schottky contacts on n-InP (1 1 1)

Abstract We have investigated the current–voltage–temperature (I–V–T) characteristics of Pd/Au/InP Schottky barrier diodes in the temperature range of 220–400 K. The I–V analysis based on thermionic emission (TE) theory shows an abnormal decrease of apparent barrier height and increase of ideality factor at low temperatures. The conventional Richardson plot exhibits nonlinearity with activation energy of 0.17 eV and the Richardson constant value of 5.63 × 10−6 A cm−2 K−2. The nonlinearity in the Richardson plot and strong dependence of Schottky barrier parameters on temperature may be attributed to the spatial inhomogeneity in the interface. Further, the homogeneous barrier height has been obtained from the linear relationship between experimentally obtained effective barrier heights and ideality factors. Φb versus (2kT)−1 plot has been drawn to obtain the mean barrier height [ Φ ¯ bo ( T = 0 K ) ] and the standard deviation (σs) at zero-bias which are found to be 0.84 eV, 138 meV, respectively. The series resistance is also estimated from the forward current–voltage characteristics of Pd/Au/InP Schottky contacts using Cheung’s method and found that it is strongly dependent on temperature and also decreases with increase in temperature.