Growth and band-gap modulation in single-crystalline Si1-xGex nanowires for nanophotonics applications

We report growth of single crystalline Si
_1-x
Ge
_x
nanowires, whose relative composition is controllably tuned over the entire composition range by Au-catalyst assisted chemical vapor syntheses. We also present experimental demonstration of the band-gap modulation from near infrared to ultraviolet regions with alloying of Si and Ge, and their spatial confinement at the nanometer scale. Our finding demonstrates that the energy band-gap of Si
_1-x
Ge
_x
nanowires can be modulated in a wider energy range, and suggests implications for group IV semiconductor nanophotonics.