Gallium-catalyzed silicon oxide nanowire growth

Silicon oxide nanowires tend to assemble into various complex morphologies through a metal-catalyzed vapor-liquid-solid (VLS) growth process. This article summarizes our recent efforts in the controlled growth of silicon oxide nanowire assemblies by using molten gallium as the catalyst and silicon wafer, SiO powder, or silane (SiH₄) as the silicon sources. Silicon oxide nanowire assemblies with morphologies of carrotlike, cometlike, gourdlike, spindlelike, badmintonlike, sandwichlike, etc. were obtained. Although the morphologies of the nanowire assemblies are temperature- and silicon source-dependent, they share similar structural and compositional features: all the assemblies contain a microscale spherical liquid Ga ball and a highly aligned, closely packed amorphous silicon oxide nanowire bunch. The Ga-catalyzed silicon oxide nanowire growth reveals several interesting new nanowire growth phenomena that expand our knowledge of the conventional VLS nanowire growth mechanism.