IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Wednesday Sessions
       Session EL+MI-WeM

Paper EL+MI-WeM3
Dilute Magnetic Semiconductors Based Upon GaP

Wednesday, October 31, 2001, 9:00 am, Room 111

Session: Spintronics III: Ferromagnetic Semiconductors
Presenter: M.E. Overberg, University of Florida
Authors: 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
S.N.G. Chu, Agere Systems
R.G. Wilson, Consultant
Correspondent: Click to Email
Dilute magnetic semiconductors (DMS), where a semiconductor host material is heavily doped with magnetic ions, could potentially be used in a variety of interesting applications and devices where the spin degree of freedom of the electron is exploited, such as quantum-based computation, electro-optic switches and modulators, to name a few. Recent theoretical calculations based upon a 5% concentration of Mn have predicted a Curie temperature for (Ga,Mn)P of roughly 100 K.@footnote 1@ The challenge is to incorporate such a large amount of magnetic ions while still maintaining the integrity of the host semiconductor. In this paper, we will report on the growth of (Ga,Mn)P:C thin films by gas source molecular beam epitaxy (GSMBE) utilizing phosphine as the group V source, and co-doped with C via a CBr@sub 4@ source for enhanced p-type doping. Results of the epitaxially grown films will be compared to (Ga,Mn)P films produced via direct implantation of Mn into GaP:C, particularly in regard to the formation of alternate phases and how this correlates with the observed magnetic behavior. X-ray diffraction (XRD) of the epitaxial films indicates the presence of the orthorhombic MnP phase in layers grown at a temperature of 600°C, and in addition the hexagonal Mn@sub 5.64@P@sub 3@ phase in films grown at a temperature of 400°C. At lower temperatures, only the Mn@sub 5.64@P@sub 3@ phase exists. The use of superlattices appears to help suppress the second phase formation, particularly in the low temperature regime. Analysis of the GaMnP:C by SQUID magnetometry suggests the presence of a ferromagnetic phase with a T@sub C@ above 50 K. This behavior is most likely due to the presence of ferromagnetic MnP. In an effort to increase the T@sub C@ above that which is possible when using Mn, the properties of Ni implanted GaP:C will also be presented. @FootnoteText@ @footnote 1@ T. Dietl, H. Ohno, F. Matsukura, J. Cibert, and D. Ferrand, Science, 287, p. 1019 (2000).