Band engineered epitaxial Ge-Si_xGe_(1-x) core-shell nanowire heterostructures

摘要

We report the growth of germanium (Ge)-silicon-germanium (Si_xGe_(1-x)) epitaxial core-shell nanowire (NW) heterostructures, with tunable Si and Ge shell content. The Ge NWs are grown using the vapor-liquid-solid growth mechanism, and the Si_xGe_(1-x) shells are grown in situ, conformally on the Ge NWs using ultrahigh vacuum chemical vapor deposition. We use transmission electron microscopy to demonstrate epitaxial shell growth, and scanning energy dispersive x-ray spectroscopy to determine the shell thickness and content. The Si and Ge shell content can be tuned depending on the SiH_4 and GeH_4 partial pressures during the shell growth, enabling band engineered core-shell NW heterostructures.