Single-Crystal, Si Nanotubes, and Their Mechanical Resonant Properties

Single-crystalline Si nanotubes (NTs) were fabricated using vapor-liquid -solid grown, Ge nanowires (NWs) as a template upon which a Si shell was deposited to first grow Ge-core, Si-shell NWs. The tips of these NWs were removed, enabling exposure of the Ge core to H2SO4 and H2O2. After removing the Ge core, single-crystalline Si NTs remained. In addition to growing these Ge-core, Si-shell NWs from a Si (111) substrate, these NWs were also grown horizontally from a vertical Si surface to enable the fabrication of horizontal NTs after focused ion-beam cutting and etching steps. The resonant properties of the Ge-core, Si-shell NW, and the Si NT after the cutting and etching steps were measured and found to have a quality factor, Q, of similar to 1800.