It was noted that a small amount of N incorporation in GaAs led to a counter-intuitive and large band-gap reduction, and to an unexpected sudden increase in the effective mass of electrons. Furthermore, both electronic and structural changes could be reversed fully and in a tunable manner by H incorporation. Here, X-ray absorption spectroscopy at the N edge were combined with ab initio simulations in order to investigate the atomic geometry of N-H complexes in hydrogenated GaAsN. In this way, experimental evidence was found that dihydrogen-N complexes with C2v symmetry were the most abundant species in hydrogenated GaAsN. This finding contradicted previous predictions of "in-line" N-H2* complexes as being the predominant species, and accounted for recent infra-red absorption experiments.

Nitrogen-Hydrogen Complex in GaAsxN1–x Revealed by X-ray Absorption Spectroscopy. G.Ciatto, F.Boscherini, A.A.Bonapasta, F.Filippone, A.Polimeni, M.Capizzi: Physical Review B, 2005, 71[20], 201301 (4pp)