Abstract

Solar cell devices have proven to be one of the promising energy resources in the future, owing to the following facts:
First and for most, solar energy is almost always available in all over the world and is an infinite source unlike fossil fuels or other finite resources. Secondly, the expenses associated with the fabrication of solar cell devices, are much less than the fabrication costs of other energy generators. This is because the sun energy is free of charges. Besides, the materials that are used in the solar cell structure are mainly from the most abundant elements on the earth such as silicon. Thirdly, this source of energy is not in conflict with the issue of natural environment pollution. In turn, it helps in eliminating the concern of contamination production, which is a direct result of fossil fuel consumption.
Having investigated for the benefits of these photovoltaic devices, we were motivated to do some significant work in improving the efficiency of these renewable energy resources. Therefore, searching for the best solar cell configurations (planar-Si and SiNW) from the literatures and modeling the optoelectrical characteristics of them by the commercial software was the first step taken in this area. In broad terms, in this work we investigated the optical and electrical characteristics of the hybrid solar cells as well as analyzing the simulation results for investigating the optimum characteristic of the device for having a higher efficiency and cost effective solar cell.
In this study, we have shown that increasing the trap density reduces the short circuit current, open circuit voltage and the FF in the planar-Si structure. Note that, the same results have been obtained in the SiNW structure except for the short circuit current which did not change by altering the trap density in the SiNW cell configuration. Furthermore, it is demonstrated that increasing the Si material length, enhances the solar cell efficiency, in both SiNW and planar-silicon structures when the dopant concentration of the silicon is 1×〖10〗^16 cm^(-3). However, it is found that when Si is doped with 6×〖10〗^18 cm^(-3) atoms, increasing the Si material thickness, does not change the current density and FF in the planar-Si structure while it improves the short circuit current and the cell efficiency in the SiNW based solar cells. By investigating the effect of dopant concentration on the planar configuration, we found that Si substrates with higher dopant concentrations did not result in a better solar cell efficiency. While, in the SiNW structure, the wires with higher dopant concentrations have shown to have a better cell efficiency. Finally, PEDOT: PSS polymer has been found to be a good candidate as the p-type material, since it can make a good heterojunction with silicon in the form of nanowires.
Therefore, this work enables the correlation of silicon material height, dopant concentration and trap density to the end solar cell performance.