AVS 53rd International Symposium
    Electronic Materials and Processing Wednesday Sessions
       Session EM+MI-WeA

Paper EM+MI-WeA3
Deposition of Doped ZnO by Pulsed Laser Deposition Utilizing Novel Ablation Targets

Wednesday, November 15, 2006, 2:40 pm, Room 2003

Session: Magnetic Semiconductors
Presenter: T.C. Kaspar, Pacific Northwest National Laboratory
Authors: T.C. Kaspar, Pacific Northwest National Laboratory
T. Droubay, Pacific Northwest National Laboratory
S.M. Heald, Pacific Northwest National Laboratory
V. Shutthanandan, Pacific Northwest National Laboratory
P. Nachimuthu, Pacific Northwest National Laboratory
C.M. Wang, Pacific Northwest National Laboratory
S.A. Chambers, Pacific Northwest National Laboratory
K.R. Kittilstved, University of Washington
C.A. Johnson, University of Washington
K.M. Whitaker, University of Washington
D.R. Gamelin, University of Washington
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Zinc oxide (ZnO) is a promising material for optical, electro-optical, magneto-optical, and spintronic applications. The desired properties of ZnO are obtained by doping the material, in which case distribution and substitution of the dopants is of prime importance. Doped ZnO nanoparticles can achieve the necessary dopant dispersion and speciation to create high-quality material exhibiting, for example, the room temperature ferromagnetism necessary for spintronic applications. However, these nanoparticles may not be as useful in practical devices as high-quality epitaxial films. To this end, we have explored the deposition of epitaxial Co- and Mn-doped ZnO thin films by pulsed laser deposition (PLD), utilizing well-characterized doped ZnO nanoparticles as the basis for the PLD ablation target material. Ablating a target which already contains the dopant in the desired substitutional environment in ZnO should allow full substitution of the dopant into the epitaxial film and reduce or eliminate the formation of secondary phases. Initial results on Co-doped ZnO films deposited on Al@sub 2@O@sub 3@(0001) from a Co:ZnO nanoparticle target indicate that smooth, epitaxial ZnO films can be obtained. Co K-edge x-ray absorption near edge spectroscopy and extended x-ray absorption fine structure show full oxidation of Co to Co(II) for all oxygen pressures explored (5x10@super -5@ - 5x10@super -2@ Torr), with substitution of Co for Zn in the ZnO lattice. Issues associated with the nanoparticle ablation targets, such as target densification using low-temperature processing, particle and droplet ejection during ablation, and localized dopant diffusion in the ablated region, will be discussed.