Illumination impact on electrical properties of Ag/0.6 wt% nanographene oxide doped poly(vinyl alcohol) nanocomposite/p-Si heterojunction

Abstract

In present study, the electrical characteristics of the Ag/0.6 wt% nGO doped poly(vinyl alcohol) (PVA)/p-Si heterojunction were investigated using current–voltage (I–V) and capacitance-voltage (C-V) measurements under dark and white light (visible light) illuminations conditions at room temperature. The nanographene oxide (nGO) powders were prepared by using improved Hummers method. The structure and morphology of as obtained nGO-PVA/p-Si heterojunction were analyzed through SEM and EDX. The main parameters such as ideality factors (n), barrier heights (Φb0), series resistances (RS), and the density of interface states (NSS) have been investigated using current–voltage measurements under dark and illumination conditions at room temperature. The difference between the barrier heights obtained from the I–V and C–V characteristics has been discussed in dark and under illumination conditions. The barrier height, ideality factor and series resistance of the Ag/nGO-PVA/p-Si Schottky heterojunction have been also determined using Cheung's and Norde methods. In addition, the interface state density (NSS) as a function of energy distribution (ESS- EV) was extracted from the forward-bias I–V measurements by taking into account the bias dependence of the effective barrier height and series resistance. These results show that the 0.6% nGO-doped poly(vinyl alcohol) nanocomposite layer prevents reaction and inter-diffusion between Ag and p-Si as well as passivating the active dangling bonds at the semiconductor surface.