Effect of illumination intensity on the electrical characteristics of Au//SiO2/n-type Si structures with GO and P3C4MT interface layer

Abstract

In this work, we searched electrical and morphological properties of the Au/SiO2/n-Si structures with graphene oxide (GO) and poly(3-cyclohexyl-4-methyl-2,5-thiophene) (P3C4MT) interface layer in dark and various illumination intensities (from dark to 100 mW cm(-2) by 20 mW cm(-2) steps) at room temperature. The formation and morphology of surfaces of GO and P3C4MT thin films were confirmed by X-ray diffraction and atomic force microscopy analysis. For this reason, the electric characteristics of an Au/(GO:P3C4MT)/SiO2/n-Si device were examined under light and dark conditions. The value of rectification ratio (998.44 at +/- 2.0 V) was calculated from the current-voltage (I-V) date in dark which also appeared that it exhibits a good photodiode characteristics at various light intensities. Likewise, the rectification ratio (RR) values increased with increasing voltage. Furthermore, the electrical characteristics like ideality factors (n), barrier heights (phi(bo)), series resistance (R-S), and saturation currents (I-0) of Au/(GO:P3C4MT)/SiO2/n-Si structures were obtained by thermionic emission theory, Cheung and Norde's method in dark and depending on the light intensity at room temperature. The results obtained from the calculation methods showed that the electrical properties are significantly dependent on the light intensity. These differences in basic electrical parameters can be due to electron-hole formation of Au/SiO2/n-type Si semiconductor structure with the GO:P3C4MT interface layer. The obtained experimental results showed that Au/(GO:P3C4MT)/SiO2/n-Si structure can be used in optoelectronic applications.