Influence of Water on the Growth Process of Ge3N4 and InP Nanowires

The germanium nitride and InP nanowires were grown using the pyrolytic decomposition products of hydrazine (N2H4), which was containing 3 mol.% H2O. In a separate set of experiments the quartz microbalance was used to study the interaction of water containing hydrazine with Ge sample in the temperature range of 450-650°C. It was established that up to 500°C only water molecules interact with Ge, forming volatile suboxide GeO. At higher temperatures GeO molecules and nitrogen precursors, produced after decomposition of hydrazine, form crystalline Ge3N4 nanowires on the Ge surface. Analysis of thermo-chemical reactions reveal that in the presence of water molecules and nitrogen precursors the formation of nitride is thermodynamically favourable than the synthesis of germanium dioxide. When InP was annealed in hydrazine at 440°C the water molecules were producing volatile In2O. After reaching the Si substrate these molecules were interacting with phosphorus vapor, producing InP nanowires.