Direct Observation of Nitrogen Location in Molecular Beam Epitaxy Grown Nitrogen-Doped ZnO
- National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8562 (Japan)
- Physics Department, University of Bologna, viale C. Berti Pichat 6/2, 40127 Bologna (Italy)
- Advanced Detector Group, L-270 Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)
ZnO is a wide band gap, naturally n-type semiconductor with great promise for optoelectronic applications. To date, however, it has proven difficult to dope p-type, a prerequisite for device fabrication. Nitrogen is widely believed to be one of the most promising dopant candidates, however, experimental results to date have been inconsistent; recent theoretical formation energy calculations have indicated that Nitrogen preferentially incorporates into the ZnO lattice in the form of a N{sub 2}{sup -} molecule at an O-site when a Nitrogen plasma source is used, leading to compensation rather than p-type doping. We show by a combination of X-ray absorption spectroscopy at the N K-edge of plasma-assisted molecular beam epitaxy grown ZnO and ab-initio simulations that in as-grown material, Nitrogen incorporates substitutionally on an O-site where it is expected to act as an acceptor. We have also observed the distinctive formation of molecular nitrogen bubbles upon rapid thermal annealing. These results suggest that effective p-type doping of ZnO with N may only be possible for metastable low-temperature growth processes.
- OSTI ID:
- 21054632
- Journal Information:
- AIP Conference Proceedings, Vol. 882, Issue 1; Conference: XAFS13: 13. international conference on X-ray absorption fine structure, Stanford, CA (United States), 9-14 Jul 2006; Other Information: DOI: 10.1063/1.2644531; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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