Applied Physics A

, Volume 88, Issue 1, pp 1–5

Growth, electronic and magnetic properties of doped ZnO epitaxial and nanocrystalline films

  • S.A. Chambers
  • D.A. Schwartz
  • W.K. Liu
  • K.R. Kittilstved
  • D.R. Gamelin
Invited paper

DOI: 10.1007/s00339-007-3948-2

Cite this article as:
Chambers, S., Schwartz, D., Liu, W. et al. Appl. Phys. A (2007) 88: 1. doi:10.1007/s00339-007-3948-2
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Abstract

We have used oxygen plasma assisted metal organic chemical vapor deposition along with wet chemical synthesis and spin coating to prepare CoxZn1-xO and MnxZn1-xO epitaxial and nanoparticle films. Co(II) and Mn(II) substitute for Zn(II) in the wurtzite lattice in materials synthesized by both methods. Room-temperature ferromagnetism in epitaxial Co:ZnO films can be reversibly activated by diffusing in Zn, which occupies interstitial sites and makes the material n-type. O-capped Co:ZnO nanoparticles, which are paramagnetic as grown, become ferromagnetic upon being spin coated in air at elevated temperature. Likewise, spin-coated N-capped Mn:ZnO nanoparticle films also exhibit room-temperature ferromagnetism. However, the inverse systems, N-capped Co:ZnO and O-capped Mn:ZnO, are entirely paramagnetic when spin coated into films in the same way. Analysis of optical absorption spectra reveals that the resonances Co(I)↔Co(II)+e-CB and Mn(III)↔Mn(II)+h+VB are energetically favorable, consistent with strong hybridization of Co (Mn) with the conduction (valence) band of ZnO. In contrast, the resonances Mn(I)↔Mn(II)+e-CB and Co(III)↔Co(II)+h+VB are not energetically favorable. These results strongly suggest that the observed ferromagnetism in Co:ZnO (Mn:ZnO) is mediated by electrons (holes).

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • S.A. Chambers
    • 1
  • D.A. Schwartz
    • 2
  • W.K. Liu
    • 2
  • K.R. Kittilstved
    • 2
  • D.R. Gamelin
    • 2
  1. 1.Fundamental Science DirectoratePacific Northwest National LaboratoryRichlandUSA
  2. 2.Department of ChemistryUniversity of WashingtonSeattleUSA

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