Temperature-dependent barrier characteristics of Ag/p-SnSe Schottky diodes based on I–V–T measurements

Abstract

The current–voltage (I–V) characteristics of Ag Schottky contacts on a Bridgman–Stockbarger grown p-type SnSe layered semiconducting material have been measured over the temperature range of 80–350 K. Their analysis based on the thermionic emission (TE) theory has revealed an abnormal decrease of zero-bias barrier height and increase of ideality factor at lower temperatures. This behaviour has been interpreted on the basis of the assumption of a Gaussian distribution of barrier heights due to barrier height inhomogeneities that prevail at the interface. The inhomogeneities are considered to have Gaussian distribution with a mean barrier height of and standard deviation of σs0 = 0.075 V at zero-bias. Furthermore, the mean barrier height and the Richardson constant values were obtained by means of the modified Richardson plot, ln(I0/T2) − (q2σ2s0/2k2T2)versus 1000/T, as 0.603 eV and 7.72 A K−2 cm−2 respectively, of which latter is close to its theoretical value of 18 A K−2 cm−2 used for the determination of the zero-bias barrier height. Hence, it has been concluded that the temperature dependence of the I–V characteristics of the Schottky barrier on p-type SnSe can be successfully explained on the basis of TE mechanism with Gaussian distribution of the barrier heights.