Abstract
ZnO is a wide band gap, naturally -type semiconductor with great promise for optoelectronic applications; the main obstacle yet to be overcome is -type doping. Nitrogen, the most promising candidate currently being pursued as a dopant, has been predicted to preferentially incorporate into the ZnO lattice in the form of a molecule at an O site when a plasma source is used, leading to compensation rather than -type doping. We demonstrate this to be incorrect by using N -edge x-ray absorption spectra and comparing them with first-principles calculations showing that nitrogen, in fact, incorporates substitutionally at O sites where it is expected to act as an acceptor. We also detect the formation of molecular nitrogen upon annealing. These results suggest that effective -type doping of ZnO with N may be possible only for low-temperature growth processes.
- Received 27 October 2005
DOI:https://doi.org/10.1103/PhysRevLett.96.045504
©2006 American Physical Society