Sub-band-gap photoconductivity in Co2+-doped ZnO
Journal Article
·
· Physical Review. B, Condensed Matter, 81(12):Article Number: 125206
Variable-temperature and polarized scanning photoconductivity measurements on Zn1-xCoxO epitaxial films allow description of Co2+-derived sub-bandgap photoionization excited states in this archetypal diluted magnetic oxide. Low-temperature (27 K) measurements demonstrate spontaneous ionization from the photo-generated 4T1(P) d-d excited state, despite the highly localized nature of this excitation. Ionization involves relaxation from this d-d state to the lower Co2+/3+ donor-type photoionization level. Variable-temperature photoconductivity measurements reveal an additional thermally assisted ionization process that enhances the d-d photoconductivity at higher temperatures. The energy barrier to thermal ionization from the 4T1(P) excited state at low temperatures is estimated to be Ea ≈ 40 meV.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 979479
- Report Number(s):
- PNNL-SA-72146; KC0201050
- Journal Information:
- Physical Review. B, Condensed Matter, 81(12):Article Number: 125206, Journal Name: Physical Review. B, Condensed Matter, 81(12):Article Number: 125206 Journal Issue: 12 Vol. 81; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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