Measurement and modelling of the characteristic parameters for silver Schottky contacts on layered p-GaSe compound in a wide temperature range

Abstract

The temperature dependent barrier characteristics of Ag/ p-GaSe Schottky barrier diodes have been analyzed in the temperature range of 70–350 K based on thermionic emission (TE) theory. Barrier height (BH) ( φ b0), ideality factor ( n) and serial resistance ( R s) have been found to be strongly temperature dependent. Decrease in the φ b0 and an increase in the n with decrease in temperature has been observed. The conventional Richardson plot exhibits non-linearity below 180 K with the linear portion corresponding to activation energy of 0.62 eV. The value of Richardson constant ( A*) turns out to be 5.15 × 10 −4 A K −2 cm −2 against the theoretical value of 60 A K −2 cm −2 for p-GaSe. It has been demonstrated that these behaviors result from the spatial BH inhomogeneities prevailing at the metal–semiconductor interface. For the interpretation of the BH inhomogeneity, multiple Gaussian distribution model developed by Jiang et al. [1] has been used. Furthermore, an expression defining temperature dependent ideality factor has been derived for the diodes with spatial BH inhomogeneities considering multiple Gaussian distribution. The temperature dependent BH of the device has shown a Double Gaussian Distribution (DGD) having mean BH ( φ ¯ b 0 ) of 1.21 and 1.08 eV with standard deviations ( σ 0) of 0.103 and 0.097 eV in the 180–350 and 70–180 K regions, respectively. φ ¯ b 0 and A* values have also been obtained as 1.209 eV, 62.8 A K −2 cm −2 and 1.097 eV, 56.8 A K −2 cm −2 from the modified Richardson plots for the respective temperature regions, respectively. These values of A* are in close agreement with that of the known value for p-type GaSe. It has been shown that these results support the predictions of the multiple GD model of spatial BH inhomogeneities in the temperature range of 70–350 K.