Nanowires are structures that have a lateral size constrained to tens of nanometers or less with an unconstrained longitudinal size. At these scales, quantum mechanical effects become predominant and hence such wires are also known as quantum wires. They have new electrical properties and so are used in the field of computing, solar cells and metamaterials. Types of Nanowires are (i) metallic (e.g., Ni, Pt, Au), (ii) semiconducting (e.g., Si, InP, GaN.), (iii) insulating (e.g., SiO2,TiO2) and molecular. Nanowires are composed of repeating molecular units either organic (e.g. DNA) or inorganic.