Surfactant-assisted chemical vapour deposition of high-performance small-diameter GaSb nanowires

Although various device structures based on GaSb nanowires have been realized, further performance enhancement suffers from uncontrolled radial growth during the nanowire synthesis, resulting in non-uniform and tapered nanowires with diameters larger than few tens of nanometres. Here we report the use of sulfur surfactant in chemical vapour deposition to achieve very thin and uniform GaSb nanowires with diameters down to 20 nm. In contrast to surfactant effects typically employed in the liquid phase and thin-film technologies, the sulfur atoms contribute to form stable S-Sb bonds on the as-grown nanowire surface, effectively stabilizing sidewalls and minimizing unintentional radial nanowire growth. When configured into transistors, these devices exhibit impressive electrical properties with the peak hole mobility of ~200 cm2V−1s−1, better than any mobility value reported for a GaSb nanowire device to date. These factors indicate the effectiveness of this surfactant-assisted growth for high-performance small-diameter GaSb nanowires.