(Invited) Surfactant-Assisted Chemical Vapor Deposition of High-Performance Small-Diameter Gasb Nanowires

Due to the intriguing physical properties, III-Sb nanowires such as GaSb have attracted extensive interest as promising channel materials for future electronics, optoelectronics and others. Although various device structures based on GaSb nanowires have been realized, further performance enhancement is still suffering from the notorious uncontrolled radial growth during the nanowire synthesis, resulting in the non-uniform and tapered nanowires with diameters much larger than few tens of nanometers. In this work, for the first time, we report the use of sulfur surfactant in the chemical vapor deposition to achieve high-performance and uniform GaSb nanowires with the diameter down to 20 nm. In contrast to the surfactant effect typically employed in the liquid phase or thin film technologies, the sulfur atoms, commonly used for the surface passivation of III-V semiconductors, are contributed to form stable S-Sb bonds on the as-grown nanowire surface, effectively stabilizing the sidewalls and thus minimizing the unintentional radial vapor-solid nanowire growth. More importantly, when configured into field-effect transistors, these nanowire devices exhibit impressive electrical properties with the peak field-effect hole mobility of ~200 cm² V^-1 s^-1, which is the best mobility value reported for any GaSb nanowire devices till now, owing to the improved gate-coupling efficiency and reduced surface carrier scattering in these thin nanowire geometry. All these results evidently indicate the effectiveness of this surfactant-assisted growth for high-performance small-diameter GaSb nanowires, significantly enhancing various device properties for practical applications.