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

摘要

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 Φ_(b0) = 0.610 eV and standard deviation of σ_(s0) = 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(I_0/ T~2) — (q~2σ_(s0)~2/2k~2T~2)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.