Two Different Growth Mechanisms for Au-Free InAsSb Nanowires Growth on Si Substrate

We present a study of Au-free InAsSb nanowire (NW) growth on Si (111) substrate under different growth parameters including V/III ratio, group Sb flow rate fraction (Sb-FRF, TMSb/(TMSb+AsH3)), and temperature. It was found that two different kinds of growth mechanisms for the Au-free InAsSb NW growth may be dominant depending on the growth parameters. At low V/III ratio and relatively high Sb-FRF, the NWs grow via vapor-liquid-solid (VLS) mode, while at high V/III ratio and relatively low Sb-FRF, they grow via vapor-solid (VS) mode. The NWs obtained by the two, growth modes show clear differences in morphology, growth direction, and crystal quality. Under VS mode, the NWs exhibit unified growth direction and a uniform composition distribution, which are beneficial to integration devices of multiple NWs. On the other hand, under VLS mode, the NWs are first reported with pure crystal phase, which will be useful for the development of single NW devices.