Abstract

We investigate the stability and electronic properties of defects formed by a substitutional nitrogen in GaAs (N-As) plus interstitial hydrogen atoms using first-principles total-energy calculations. We find the formation of strong N-As-H bond when a single H atom is incorporated in the lowest-energy bond centered (BC) position. This defect induces an electrically active level in the GaAs band gap. When two H atoms are incorporated, we find the stable N-As-H-2* complex as the lowest-energy configuration, with one H atom at the BC position and the second H atom at an antibonding position. The electronic structure of this complex shows the passivation of the gap level restoring the GaAs band gap. (C) 2002 American Institute of Physics.