Near-edge states induced by hydrogen inclusion in gallium arsenide

The equilibrium geometries and the electronic structures for different loca tions of H atoms and ions in GaAs have been evaluated by first-principle lo cal density functional methods. Discrete near-edge levels are induced in th e bandgap by the interactions of hydrogen with the GaAs lattice, as well as by charge effects in the case of H ions. Radiative transitions between tho se conduction-band and valence-band near-edge states account for the main f eatures of the emission bands observed in the photoluminescence spectra of hydrogenated III-V compounds.