This book begins with a overview of silicon nanowires. A chemical method for synthesis of Silicon Nanowir at room temperature has been discussed in this book.The effect of variation of different reaction parameter like concentration of solution and reaction time has extensively been investigated. It is observed that the size of nanostructure depends on the reaction parameters. This observation suggests some way to control the length and diameter of synthesized nanostructures. The experimental findings to control the synthesized nanostructure have also been incorporated. Optical, structural and electronic characteristics of silicon naowires have been presented. Enhanced optical absorption and modified reflection property are observed in silicon nanowires, what suggests the potential application of synthesized structure in photovoltaic devices.