Optoelectronic properties of Au/n-type Si semiconductor structures with SiO2 interlayer

Abstract

In this study, we investigated the effect of light intensity on electrical and photovoltaic properties using current-voltage (I–V) measurements at room temperature of Au/n-type Si structures with SiO2 interface layer. At each light intensity, the obtained main electrical characteristics such as ideality factors (n), barrier heights (Φbo), rectification ratios (RR), saturation currents (I0) and series resistances (RS) of Au/SiO2/n-type Si structures were calculated from both thermionic emission (TE) and Cheung methods using I–V measurements and compared to each other. Experimental results showed that while the n and I0 values increased with the increase in the light intensity, the Φbo and RR values decreased. While the ideality factor values obtained using the TE method ranged between 1.973 (at dark) and 2.250 (for 100 mW/cm2), these values were obtained between 3.227 and 3.482 using the Cheung method. At the same time, while the barrier height values obtained using the TE method ranged between 0.865 eV (at dark) and 0.817 eV (for 100 mW/cm2), these values were obtained between 0.773 eV and 0.742 eV using the Cheung method. It was observed that while the n values obtained from TE theory were smaller than the values obtained from the Cheung method, the Φbo values were larger than the values obtained from the Cheung function. Furthermore, for the Au/SiO2/n-type Si structures, the photovoltaic parameters such as short circuit current (Isc) and open circuit voltage (Voc) and photocurrent (Iph) were examined under dark, daylight and various light intensities (from 20 to 100 mW/cm2).