Effects of N on the electronic structures of H defects in III-V semiconductors

Nitrogen has profound effects on the electronic structure of III-V semiconductors, as adding a few percent of N can drastically lower the band gap. Hydrogen, on the other hand, is an important impurity in III-V semiconductors. Using first-principles band structure calculations we find that N can also qualitatively alter the electronic behavior of hydrogen in III-V semiconductors. We show that in GaAsN and GaPN a H atom bonds preferentially to the more electronegative N and can act as a donor in its own right. At high Fermi energy and H concentration, the H-2* complex associated with N is stabilized. The formation of the H-2* removes the effect of N on the band gap, restoring the gap of GaAs. For GaPN, the calculated local vibrational frequencies and isotope shifts of H-2* are in good agreement with experiments. (C) 2003 Elsevier B.V. All rights reserved.