Comparative study of macroporous silicon-based photovoltaic characteristics using indium tin oxide-silicon and pn-silicon junction based devices.

We report highly ordered macroporous silicon (Si)-based photovoltaic characteristics using indium tin oxide (ITO)/n-Si and pn-Si junction-based devices. The detailed fabrication processes including new controlled ITO etching are presented. Theoretical device simulations are performed to understand the presented device structures and propose an optimum device design based on processing limitations. The performance of ITO/n-Si junction devices directly depends on the conformal ITO coating along the pore surface. While pn-Si junction device requires additional doping step, the device can overcome the limitation of ITO conformal coating, especially for a device with high-aspect-ratio macropore structures. Experimental results also support the simulation analysis. The three-dimensional structural properties of well-defined macroporous Si coupled with the formation of photovoltaic devices are attractive for multi-functional applications.