Growth and optical properties of catalyst-free InP nanowires on Si (1Â 0Â 0) substrates

Catalyst-free InP nanowires were grown on Si (1 0 0) substrates by metal-organic chemical vapor deposition. Morphology, crystal structure, photoluminescence, and Raman scattering properties of the nanowires were investigated. Most nanowires are long and straight; the angles between the nanowires and the Si substrate are diverse. The photoluminescence peak shows blue-shift from the band gap energy of bulk InP. Both the blue-shift of photoluminescence peak and the full width at half-maximum of photoluminescence spectrum increase with decreasing nanowires growth temperature. Due to laser-induced heating, the TO and LO phonon peaks of the nanowires reveal downshift and asymmetric broadening compared with those of bulk InP at room temperature.