Experimental and ab-initio studies of temperature dependent InN decomposition in various ambient

N-polarity InN layers grown on (0001) sapphire substrates by hydride vapor phase epitaxy (HVPE) were annealed in atmospheric N2, H2, H2+NH3, or N2+NH3 ambient at various temperatures. In the N2 ambient, InN decomposition became significant above 600 C, whereas in the H2 ambient, InN layers reacted with H2 and decomposed at very low temperatures above 350 C. The process of InN decomposition was also investigated using a first-principles calculation. In a system free from H2, the rate-limiting process was found to be desorption of N atoms from the surface as atomic N (N*), whereas in the H2 ambient, the desorption of In atoms as In, InH or InH3 is the rate-limiting process. Thus, the decomposition reactions of InN layers in the ambient in the presence and absence of H2 are different. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)