Ge/Si core/shell nanowires with controlled low temperature grown Si shell thickness

Ge/Si core/shell nanowires are fabricated with narrow (20 nm) Ge core and thin (2 nm) Si shell. Ge nanowires are prepared by vapor–liquid–solid (VLS) chemical vapor deposition (CVD). The low-temperature (450 °C) process by using Si2H6 gas as a Si CVD source is essential to form ultrathin layer of epitaxial Si film onto very narrow Ge nanowires. Accumulation of holes in Ge nanowires confined in the Si shell is confirmed by electrical measurement.