When dimensions of material approach nanoscale, they often reveal startling properties. These unique properties when compared to bulk material make them interesting candidates for new technologies. In a race to sustain Moore’s Law, silicon nanowires which possess remarkable properties diverse from bulk-silicon have gained notable attention. With advancement in technology engineers have mastered the art of fabrication of nanowires, but there exists a big gap in understanding various phenomena at this scale. The aim of this work is to bridge the gap and give an insight into some interesting properties and application of silicon nanowires. Using top-down lithography Silicon nanowires are fabricated and various mechanical and electrical properties are studied. The use of functionalized silicon nanowires for gas detection is demonstrated with very large sensitivity and detection window reported for the first time.