Deep nitrogen-induced valence- and conduction-band states in GaAs1-xNx
2003 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 68, no 3Article in journal (Refereed) Published
Most studies of the anomalous electronic properties of the GaAs1-N-x alloy have focused on near-edge states, but x-ray spectroscopic experiments [V. N. Strocov et al., Phys. Status Solidi B 233, RI (2002)] have now revealed anomalous properties deep inside the valence and conduction bands. Indeed, whereas N p character is found in GaN in the energy region near the valence-band maximum (VBM), when similar to3% N is introduced into GaAs one finds that N p character exists about 2-3 eV below the VBM and as two narrow peaks just above the conduction-band minimum. First-principles calculations of the N p character in Ga32As31N and GaN show that the valence resonances are due the fact that the VBM of GaAs0.97N0.03 itself lies > 2 eV above that of GaN. Thus, there is no need to involve an N--> As charge transfer to explain the data. This conclusion is further confirmed by our calculated valence--> conduction-band absorption spectra. We also show that the broken-symmetry core-hole calculations are necessary to explain, within the local density approximation (LDA), the energy of the N 1s<--valence-band transitions. As to the conduction-band peaks observed experimentally in the x-ray absorption, our LDA calculations do not reveal the sharp peaks seen in the measured spectra, leading to the possibility that the latter may not be related to substitutional N.
Place, publisher, year, edition, pages
2003. Vol. 68, no 3
broken-symmetry approach, x-ray-emission, electronic-structure, core-hole, ii-vi, semiconductors, spectra, absorption, gan
IdentifiersURN: urn:nbn:se:kth:diva-22799ISI: 000185229600069OAI: oai:DiVA.org:kth-22799DiVA: diva2:341497
QC 201005252010-08-102010-08-10Bibliographically approved