Investigation of the structural and temperature-dependent electrical properties of MZnO (M = Ce and Sm) Schottky diode devices fabricated using the sol-gel spin-coating technique

Abstract

In the present study, the Schottky diode devices based on Ce and Sm co-doped ZnO thin films were fabricated using the sol–gel spin-coating technique with Pd and Pt as Schottky contacts. The structural and electrical properties of the fabricated Schottky diode devices were investigated at room temperature and in the temperature range of 320–160 K. The crystalline structure of the prepared films was studied using X-ray diffraction spectroscopy. The I–V characteristics of the fabricated Schottky diode devices based on Pd and Pt Schottky contacts manifest good diode behavior with the rectification of nine and ten orders of magnitudes, respectively. The ideality factor for Pd-based Schottky diode was found to decrease with temperature, and the lowest value obtained at 160 K was 1.3, while for the Pt-based Schottky diode, the ideality factor was found to increase with decreasing temperature. Moreover, by using two Gaussian models, the barrier height for Pt Schottky diodes was found to decrease with decreasing temperature indicating the inhomogeneity in the barrier height. Furthermore, alongside the thermionic emission theory, the fabricated Schottky diode parameters were also analyzed with Cheung–Cheung and the modified Nord methods. Finally, the current transport mechanism in both fabricated Pd and Pt was found to be controlled by an Ohmic, trap-filled voltage and spacecharge- limited current mechanisms in the low, moderate and higher voltage bias, respectively.