Defect-free InAs nanowires self-catalyzed growth on graphene/Ge by molecular beam epitaxy

InAs nanowires (NWs) self-catalyzed grown on graphene surface frequently exhibit a large number of stacking-fault defects. However, the control of these defects in InAs NWs still remains a large challenge, which significantly limits the applications of InAs NWs in electronics and optoelectronics. In this work, the self-catalyzed growth of InAs NWs on graphene/Ge substrate by molecular beam epitaxy (MBE) is systematically investigated. Growth models for InAs NWs and parasitic islands on graphene/Ge are developed. Through rational design of growth parameters, the self-catalyzed growth of defect-free InAs NWs on graphene surfaces is ultimately achieved. Our experimental results indicate that lower growth temperature can effectively suppress the formation of stacking-fault defects in InAs NWs, no visible stacking-fault defects are observed in the samples grown below 510 °C, and the intrinsic mechanism for this is clarified with the density functional theory (DFT) calculations.