GaN Nanowire Growth on Si Substrate by Utilizing MOCVD Methods

Abstract

Abstract:We have grown GaN nanowires by the low pressure MOCVD method on Ni deposited oxidized Si surface and have established optimum conditions by observing surface microstructure and its photoluminescence. Optimum growth temperature of 880℃, growth time of 30 min, TMG source flow rate of 10 sccm have resulted in dense nanowires on the surface, however further increase of growth time or TMG flow rate has not increased the length of nanowire but has formed nanocrystals. On the contrary, the increase of ammonia flow has increased the length of nanowires and the coverage of nanowire over the surface. The shape of nanowire is needle-like with a Ni droplet at its tip; the length is tens of micron with more than 40 nm in diameter. Low temperature photoluminescence obtained from the sample at optimum growth condition has revealed several peaks related to exciton decay near band-edge, but does not show any characteristic originated from one dimensional quantum confinement. Strong and broad luminescence at 2.2 eV is observed from dense nanowire samples and this suggests that the broad band is related to e-h recombination at the surface state in a nanowire. The current result is implemented to the nanowire device fabrication by nanowire bridging between micro-patterned neighboring Ni catalysis islands.

Growth of oriented GaN nanowires by controlling nucleation conditions

“…Semiconductor nanowires (NWs) are promising materials for novel electronic and optoelectronic devices . Metal organic chemical vapor deposition (MOCVD) is widely employed to synthesize GaN NWs via vapor‐liquid‐solid (VLS) mechanism with Ni, Au, Pt and Fe as catalyst . Normally, vertical aligned NWs are preferred for some applications .…”