N-H$_{n}$ complexes in GaAsN:H containing more than two H atoms

The III-N-V alloys have attracted much attention because of a large reduction of the band gap that occurs for N concentrations of a few percent. The hydrogenation of these alloys eliminates the effect of N.[1] IR experiments and theory revealed the properties of an NH$_{2}$ complex that can cause these novel effects.[2] Further studies by theory [3] and experiment [4] suggest the formation of defect complexes that contain more than two H atoms per N atom. In the present talk, new IR data provide experimental clues about the structures of NH$_{n}$ defect complexes with n$>$2 that have been found in GaAsN samples that were hydrogenated at reduced temperature. [1] A. Polimeni et al., Phys. Rev. B \textbf{63}, 201204 (2001). [2] S. Kleekajai et al., Phys. Rev. B \textbf{77}, 085213 (2008) and the references contained therein. [3] A.A. Bonapasta et al., Phys. Rev. Lett. \textbf{98}, 206403 (2007). [4] M. Berti et al., Phys. Rev. B \textbf{76}, 205323 (2007).