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 nanometers. However, high-quality and uniform GaSb NWs with diameters down to 20 nm have been prepared by using a sulfur surfactant technique in our previous works, which efficiently stabilizes the high-energy sidewalls for homogenous NW formation during the chemical vapor deposition (CVD) process.¹ At the same time, the growth direction and corresponding carrier mobilities are still found to be heavily depended on the NW diameters, in which the <111>-orientated GaSb NWs exhibit the highest hole mobility because of the optimized surface passivation and roughness in preference to the minimized surface traps, indicating the potential applications of these phase pure NWs for high-performance electronics.²

Using CMOS-compatible Pd catalysts and a complementary experimental and theoretical approach, we demonstrate successfully the formation of high-performance, <111>-oriented GaSb nanowires (NWs) via vapor-solid-solid (VSS) growth mode in surfactant-assisted chemical vapor deposition. When back-gated field-effect transistors (FETs) are fabricated using these NWs, the Pd-catalyzed GaSb NW exhibits a superior peak hole mobility of ~330 cm²V^-1s^-1, and this value is close to the mobility limit for a NW channel diameter of ~30 nm with a free carrier concentration of ~10¹⁸ cm^-3, indicating excellent homogeneity of the NW phase purity, the growth orientation, the surface morphology and the electrical characteristics. Contact printing process is also used to fabricate large-scale assembly of Pd-catalyzed GaSb NW parallel arrays, and a calculated peak hole mobility of ∼65cm²V^-1s^-1 is achieved, confirming the potential construction and application of these high-performance electronic devices. ³

Acknowledgment

We acknowledge “Qilu young scholar” program of Shandong University.

References

1. Yang, Z.-x.; Han, N.; Fang, M.; Lin, H.; Cheung, H.-Y.; Yip, S.; Wang, E.-J.; Hung, T.; Wong, C.-Y.; Ho, J. C., Surfactant-assisted chemical vapour deposition of high-performance small-diameter GaSb nanowires. Nature Communications 2014, 5, 5249.

2. Yang, Z.-x.; Yip, S.; Li, D.; Han, N.; Dong, G.; Liang, X.; Shu, L.; Hung, T. F.; Mo, X.; Ho, J. C., Approaching the Hole Mobility Limit of GaSb Nanowires. Acs Nano 2015, 9 (9), 9268-9275.

3. Yang, Z.-x.; Liu, L.; Yip, S.; Li, D.; Shen, L.; Zhou, Z.; Han, N.; Hung, T. F.; Pun, E. Y.-B.; Wu, X.; Song, A.; Ho, J. C., Complementary Metal Oxide Semiconductor-Compatible, High-Mobility,< 111>-Oriented GaSb Nanowires Enabled by Vapor-Solid-Solid Chemical Vapor Deposition. ACS nano 2017, DOI: 10.1021/acsnano.7b01217.