Analysis of temperature dependent electrical characteristics of Au/GaSe Schottky barrier diode improved by Ce-doping

Abstract

In this paper, structural and electrical properties of p-type undoped and Ce-doped (0.1 at%) GaSe single crystals grown by using modified Bridgman method were investigated. The XRD analysis showed that both undoped and Ce-doped GaSe single crystals had hexagonal structure with preferred orientation along (004). The Schottky diodes were realized by Au contacts on GaSe wafers. The electrical characteristics of the Ce-doped GaSe device based on the current-voltage were found to be better compared to the undoped GaSe device. The electrical measurements were carried out in the temperature interval of 100-360 K. The temperature dependent ideality factor n, the barrier height Φb, the saturation current I0, the series resistance Rs and the interface states density Nss, were determined by using the thermionic emission (TE) theory. Based on this theory, it was observed that the ideality factor and series resistance decreased while the barrier height and the saturation current increased with increasing temperature. From the plot of Φb vs. 1000/T, temperature dependent I–V characteristics of Au/GaSe:Ce Schottky diode revealed the existence of a double Gaussian distribution with mean barrier height values of 1.35 and 0.83 eV and standard deviation (σ0) of 161 and 96 meV, respectively. The Norde method was used to determine the series resistance and it was observed that the series resistance decreased with increasing temperature.