Interplay of VLS and VS growth mechanism for GaN nanowires by a self-catalytic approach

The variation of reactor pressure on the self-catalytic assisted growth of gallium nitride (GaN) nanowires (NWs) by chemical vapour deposition demonstrates the transition of a one-dimensional structure from entangled to quasi-aligned vertical NWs. Entangled NWs grown at atmospheric pressure display liquid Ga droplets on the apex, which is absent on the vertical NWs grown at reduced pressure. The correlation between the evolution of a distinct morphology reveals that the reactor pressure perturbs the growth modes and suggests that the entangled NWs follow the vapor-liquid-solid mechanism and the growth of vertical NWs is likely to be vapour-solid driven. mu-Raman and photoluminescence studies exhibit the high optical quality of both the entangled and vertical NWs.