Aperiodic Silicon Nanowire Arrays: Fabrication, Light Trapping Properties and Solar Cell Applications

Solar photovoltaic (SPV) is capable of providing the most feasible carbon-free route to the worldwide traditional power consumption. During the last decade, there has been tremendous development in silicon wafer based photovoltaic (PV) cells technology and today commercial silicon PV cells over 20 % efficiencies have been achieved. However, large-scale implementation of silicon wafer PV is currently not economical because of their high cost as compared to traditional power sources. One of the primary cost components for silicon PV cells is the starting silicon wafer, which requires extensive purification to maintain reasonable performance. Therefore, development of efficient and low cost PV devices is extremely important. Silicon nanowires (SiNWs) are a very promising candidate for next generation PV. The SiNW arrays exhibit low reflection, strong broadband light absorption and may be used as antireflection surface in solar cells. In addition to enhanced optical properties, nanowire arrays also have the potential for efficient charge carrier collection across the nanowire diameter for radial junction (homo/hetro p-n junctions) solar cells and therefore may relax high quality material requirement, enabling lower-cost PV cells. In the chapter, a short review of aperiodic SiNW arrays fabrication by silver assisted wet chemical etching method, their light trapping properties and PV applications with emphasis on SiNW arrays based solar cells would be presented. Finally, challenges in effective use of SiNW arrays in PV devices and future perspective would also be briefly discussed.