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

Abstract

The germanium nitride and InP nanowires were grown using the pyrolytic decomposition products of hydrazine (N 2 H 4 ), which was containing 3 mol.% H 2 O. 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 Ge 3 N 4 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 In 2 O. After reaching the Si substrate these molecules were interacting with phosphorus vapor, producing InP nanowires.

Pre-stages of the Formation of Ge3N4 on the Surface of Syngle-crystal Germanium in Hydrazine Vapors

“…The curves shown in this Figure show a regular increase in the amount of "adsorbed" vapors and the etching rate of the germanium surface with increasing storage time. Since the etching process is caused by water vapor contained in hydrazine (Ge(s)+H 2 O(g)→GeO(g)+H 2 (g)) 7 , it can be assumed that hydrazine is gradually moistened during its storage. (We point out again that the change the degree of moisture cannot be determined by the physical characteristics of hydrazine.)…”