the bulk synthesis of highly crystalline noncatalytic low melting metals such as β - gallium oxide tubes , nanowires , and nanopaintbrushes is accomplished using molten gallium and microwave plasma containing a mixture of monoatomic oxygen and hydrogen . gallium oxide nanowires were 20 - 100 nm thick and tens to hundreds of microns long . transmission electron microscopy revealed the nanowires to be highly crystalline and devoid of any structural defects . results showed that multiple nucleation and growth of gallium oxide nanostructures can occur directly out of molten gallium exposed to appropriate composition of hydrogen and oxygen in the gas phase . these gallium oxide nanostructures are of particular interest for opto - electronic devices and catalytic applications .