Abstract
This thesis aims to develop several processes of electrochemical etched porous silicon for either energy storage devices or demonstrating its potential for silicon-based solar cells. Silicon, the second most abundant material on earth, has been utilized in a wide range of regimes including batteries, semiconductor industry, and solar cells due to its low cost and well-developed technology. Porous silicon (PSi), as a functional material either due to its intrinsic property or the porous structure, has been presented to be fabricated by electrochemical etching, which is a facile and cost-effective method for producing porous silicon in a large scale. For lithium-ion batteries, the high theoretical capacity makes it a suitable candidate for anode material. However, the volume expansion during lithiation/delithiation limits its cycling performance. In this thesis, SiNPs produced from PSi has been exploited to lithium-ion batteries with excellent capacitance, columbic efficiency, and cycling retention. Porous silicon is further exploited as electrodes of supercapacitors after few-layer of graphene coating, showing competitive specific capacitance and stable cycling retention. In the last part of the results, porous silicon films and quasi-monocrystalline silicon films possessing extraordinary flexibility are exfoliated from silicon wafers, showing good potential for reusing the silicon wafers to reduce cost of Si-based solar cells.