Temperature dependence of current–voltage characteristics of the Cd/CdS/n-GaAs/In sandwich structure

Abstract

In the present paper, Cd/CdS/n-GaAs/In sandwich structure grown by Successive Ionic Layer Adsorption and Reaction (SILAR) technique. The temperature effect on the current–voltage (I–V) characteristics has been investigated. For structural properties, the XRD and SEM measurements have been done and it is seen that films exhibit polycrystalline behavior. This structure has clearly demonstrated rectifying behavior by the I–V curves at room temperature. The temperate effect on the barrier height, ideality factor and series resistance parameters have been investigated in 80–320K temperature range. The experimental values of barrier height and ideality factor have been calculated as 0.738eV and 1.263 at 320K and 0.234eV and 4.776 at 80K, respectively. While the ideality factor increases with decreasing temperature, the barrier height decreases. The variation of apparent barrier height and ideality factor with temperature can be explained considering lateral inhomogeneities in the barrier height in nanometer scale lengths at the CdS/n-GaAs interface. From C–V characteristics, built in voltage, Fermi energy level, effective barrier height and doping concentration of substrate values of this structure were calculated as a function of measurement frequency.