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    Electronics Wednesday Sessions
       Session EL+MI-WeM

Paper EL+MI-WeM7
Epitaxial Growth of GaMnN

Wednesday, October 31, 2001, 10:20 am, Room 111

Session: Spintronics III: Ferromagnetic Semiconductors
Presenter: G.T. Thaler, University of Florida
Authors: G.T. Thaler, University of Florida
M.E. Overberg, University of Florida
C.R. Abernathy, University of Florida
S.J. Pearton, University of Florida
N. Theodoropoulou, University of Florida
A.F. Hebard, University of Florida
Correspondent: Click to Email
Dilute magnetic semiconductors (DMS) offer the use of the spin degree of freedom of the electron in addition to its charge in device applications. Recent theoretical calculations have predicted a Curie temperature for GaMnN of roughly 400 K.@footnote 1@ In this talk we will discuss the feasibility of growing GaMnN via gas-source molecular beam epitaxy. Mn levels up to 47% as determined by Auger electron spectroscopy (AES) have been obtained in GaMnN. X-ray diffraction (XRD) shows no evidence of second phase formation in films with Mn concentrations less than 9%. Addition of Mn to the GaN changes the conductivity from highly conductive n-type to highly resistive, suggesting that at least some of the Mn behaves as a deep acceptor. Nominally semi-insulating GaMnN with a Mn concentration of ~5% shows paramagnetic behavior with a saturation moment per Mn of 3.9 Bohr magnetons, suggesting that much of the Mn is substitutional. Increasing the growth temperature increases the electron concentration due to enhanced incorporation of nitrogen vacancies. The increased carrier concentration produces what appears to be a ferromagnetic material, but with a low Curie temperature of ~100K. Similar studies on p-GaMnN will be discussed in this talk as will the effect of adding Al to the GaMnN. @FootnoteText@ @footnote 1@ T. Dietl, H. Ohno, F. Matsukura, J. Cibert, and D. Ferrand, Science, 287, p. 1019 (2000).