Crystalline GaSb nanowires synthesized on amorphous substrates: From the formation mechanism to p-channel transistor applications

In recent years, because of the narrow direct bandgap and outstanding carrier mobility, GaSb nanowires (NWs) have been extensively explored for various electronics and optoelectronics. Importantly, these p-channel nanowires can be potentially integrated with n-type InSb, InAs, or InGaAs NW devices via different NW transfer techniques to facilitate the III-V CMOS technology. However, until now, there have been very few works focusing on the electronic transport properties of GaSb NWs. Here, we successfully demonstrate the synthesis of crystalline, stoichiometric, and dense GaSb NWs on amorphous substrates, instead of the commonly used III-V crystalline substrates, InAs, or GaAs NW stems as others reported. The obtained NWs are found to grow via the VLS mechanism with a narrow distribution of diameter (220 ± 50 nm) uniformly along the entire NW length (>10 μm) with minimal tapering and surface coating. Notably, when configured into FETs, the NWs exhibit respectable electrical characteristics with the peak hole mobility of ∼30 cm² V^-1 s^-1 and free hole concentration of ∼9.7 × 10¹⁷ cm^-3. All these have illustrated the promising potency of such NWs directly grown on amorphous substrates for various technological applications, as compared with the conventional MOCVD-grown GaSb NWs.