An investigation into the conversion of In(2)O(3 )into InN nanowires

Straight In(2)O(3 )nanowires (NWs) with diameters of 50 nm and lengths ≥2 μm have been grown on Si(001) via the wet oxidation of In at 850°C using Au as a catalyst. These exhibited clear peaks in the X-ray diffraction corresponding to the body centred cubic crystal structure of In(2)O(3 )while the photoluminescence (PL) spectrum at 300 K consisted of two broad peaks, centred around 400 and 550 nm. The post-growth nitridation of In(2)O(3 )NWs was systematically investigated by varying the nitridation temperature between 500 and 900°C, flow of NH(3 )and nitridation times between 1 and 6 h. The NWs are eliminated above 600°C while long nitridation times at 500 and 600°C did not result into the efficient conversion of In(2)O(3 )to InN. We find that the nitridation of In(2)O(3 )is effective by using NH(3 )and H(2 )or a two-step temperature nitridation process using just NH(3 )and slower ramp rates. We discuss the nitridation mechanism and its effect on the PL.