An outline of the synthesis and properties of silicon nanowires

We consider some of the significant aspects of Silicon nanowires (NWs), referring to their various modes of fabrication and their measured properties. Lithographic patterning as well as individual NW synthesis, e.g., through chemical vapor deposition based processes, has been utilized for their fabrication. It is seen that the properties of these nanostructures, to a large extent, are determined by the enhanced surface area to volume ratio and defects play a relatively major role. A diminished size also brings forth the possibility of quantum confinement effects dictating their electronic and optical properties, e.g., where NWs can possess a direct energy gap in contrast to the indirect bandgap of bulk Si. While new challenges, such as enhanced Ohmic contact resistance, carrier depletion–which can severely influence electrical conduction, and surface passivation abound, there also seem to be exciting opportunities. These include, e.g., high sensitivity sensors, nanoelectromechanical systems, and reduced thermal conductivity materials for thermoelectrics. Much preliminary work has been done in these areas as well as investigating the possible use of Si NWs for transistor applications, photovoltaics, and electrochemical batteries etc., all of which are briefly reviewed.