Janotti A, Zhang S B, Wei Su-Huai, Van de Walle C G
National Renewable Energy Laboratory, Golden, Colorado 80401.
Phys Rev Lett. 2002 Aug 19;89(8):086403. doi: 10.1103/PhysRevLett.89.086403. Epub 2002 Aug 5.
Nitrogen has profound effects on the electronic structure of GaAs, as only a few percent of N can drastically lower the band gap. It is, however, not recognized that the same amount of N can also qualitatively alter the electronic behavior of hydrogen: First-principles calculations reveal that, in GaAsN, a H atom bonds to N and can act as a donor in its own right, whereas in GaAs and GaN, H is amphoteric, causing passivation instead. At high Fermi energy and H concentration, a N complex with two H was found to have lower energy than the single-H configuration. By removing the effect of N, this electrically inactive complex restores the gap of GaAs.
