No abstract

We present an ab-initio investigation of the structural, electronic, and optical properties of substitutional nitrogen doping of a-TiO 2 . Through observation of multiple N-doped amorphous structures, we find additional localized tail states within the band gap. Some structures show these states nearly 1 eV above the valence band, while most structures show these states very close to the valence band edge. We also observe a general trend of increasing cohesive energy with increasing distance between nitrogen impurities, suggesting the tendency for nitrogen to form localized clusters within the material.