Complementary Metal Oxide Semiconductor-Compatible, High- Mobility, <111>-Oriented GaSb Nanowires Enabled by Vapor-Solid- Solid Chemical Vapor Deposition

Using CMOS-compatible Pd catalysts, we demonstrate successfully the formation of high-mobility and <111>-oriented GaSb nanowires (NWs) via vapor-solid-solid (VSS) growth in surfactant-assisted chemical vapor deposition through a complementary experimental and theoretical approach. In contrast to NWs formed by conventional vapor-liquidsolid (VLS) mechanism, cylindrical-shaped Pd5Ga4 catalytic seeds are present in our Pdcatalyzed VSS-NWs. The stoichiometric composition is found to have the lowest crystal surface energy when constituted as solid catalysts, contributing to minimal surface diffusion and optimal in-plane interface orientation at the seed/NW interface for efficient epitaxial NW nucleation. All these VSS characteristics lead to the NW growth with slender diameter distribution (down to 26.9 ± 3.5 nm), uniform growth orientation (over 95 % NWs grown in <111> orientation for a wide diameter range of between 10 and 70 nm), and enhanced crystallinity. 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 the excellent homogeneity of NW phase purity, growth orientation, surface morphology and electrical characteristics. Contact printing process is also used to fabricate largescale assembly of Pd-catalyzed GaSb NW parallel arrays, confirming the potential constructions and applications of these high-performance electronic devices.