AVS 52nd International Symposium
    Magnetic Interfaces and Nanostructures Thursday Sessions
       Session MI-ThA

Paper MI-ThA4
Characterization of Transition Metal Doped MOCVD-Grown ZnO Epifilms and Nanostructures

Thursday, November 3, 2005, 3:00 pm, Room 204

Session: Magnetic Oxides
Presenter: D. Hill, Rutgers University
Authors: D. Hill, Rutgers University
R. Gateau, Rutgers University
J.F. Veyan, Univ. Tech. Frederico Santa Maria
L.S. Wielunski, Rutgers University
S. Guha, Rutgers University
R.A. Bartynski, Rutgers University
D.A. Arena, Brookhaven National Lab
J. Dvorak, Montana State University
P. Wu, Rutgers University
Y. Lu, Rutgers University
F. Cosandey, Rutgers University
V. Poltavets, Rutgers University
M. Greenblatt, Rutgers University
Correspondent: Click to Email
ZnO is a wide bandgap (~3.3 eV) semiconductor that recently has been identified as a promising DMS candidate for room temperature spintronics. We have characterized the chemical, compositional, and magnetic properties of transition metal- (TM-) doped ZnO epitaxial thin films and nanostructures grown by MOCVD. The films and nanopillars were doped with Mn or Fe either by ion implantation or in-situ during MOCVD growth. RBS ion channeling shows a minimum yield < 2% for the ZnO epi films indicating excellent crystallinity. The minimum yield is much higher for the ion implanted samples, but improves dramatically upon annealing. Soft x-ray absorption spectroscopy (SXAS) indicates that the TM dopant may be in either the 2+ or 3+ oxidation state, depending upon annealing history. In-situ doped films exhibit oxidation states similar to ion implanted films that have been annealed. SQUID magnetometry measurements show that both the implanted and annealed films and nanostructures exhibit hysteretic M vs. H curves at temperatures as high as liquid nitrogen temperature. M(T) curves show a small paramagnetic component at 5 K, but the majority of the magnetization remains up to room temperature. TM-ion implanted MOCVD-grown ZnO nanotips show relatively uniform TM concentration (<~ 5%) throughout the tip, and TEM images show no indication of secondary phase formation or metal clustering upon annealing to temperatures as high as 700C. @FootnoteText@ @footnote 1@Supported by NSF grant # ECS-0224166 .