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Proceedings Paper

Multifunctional III-nitride dilute magnetic semiconductor epilayers and nanostructures as a future platform for spintronic devices
Author(s): Matthew H. Kane; Martin Strassburg; Ali Asghar; Qing Song; Shalini Gupta; Jayantha Senawiratne; Christoph Hums; Ute Haboeck; Axel Hoffmann; Dmitry Azamat; Wolfgang Gehlhoff; Nikolaus Dietz; Z. John Zhang; Christopher J. Summers; Ian T. Ferguson
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Paper Abstract

This work focuses on the development of materials and growth techniques suitable for future spintronic device applications. Metal-organic chemical vapor deposition (MOCVD) was used to grow high-quality epitaxial films of varying thickness and manganese doping levels by introducing bis-cyclopentadienyl as the manganese source. High-resolution X-ray diffraction indicates that no macroscopic second phases are formed during growth, and Mn containing films are similar in crystalline quality to undoped films Atomic force microscopy revealed a 2-dimensional MOCVD step-flow growth pattern in the Mn-incorporated samples. The mean surface roughnesses of optimally grown Ga1-xMnxN films were almost identical to that from the as-grown template layers, with no change in growth mechanism or morphology. Various annealing steps were applied to some of the samples to reduce compensating defects and to investigate the effects of post processing on the structural, magnetic and opto-electronic properties. SQUID measurements showed an apparent ferromagnetic hysteresis behavior which persisted to room temperature. An optical absorption band around 1.5 eV was observed via transmission studies. This band is assigned to the internal Mn3+ transition between the 5E and the partially filled 5T2 levels of the 5D state. The broadening of the absorption band is introduced by the high Mn concentration. Recharging of the Mn3+ to Mn2+ was found to effectively suppress these transitions resulting in a reduction of the magnetization. The structural quality, and the presence of Mn2+ ions were confirmed by EPR spectroscopy, meanwhile no Mn-Mn interactions indicative of clustering were observed. The absence of doping-induced strain in Ga1-xMnxN was observed by Raman spectroscopy.

Paper Details

Date Published: 25 March 2005
PDF: 12 pages
Proc. SPIE 5732, Quantum Sensing and Nanophotonic Devices II, (25 March 2005); doi: 10.1117/12.582980
Show Author Affiliations
Matthew H. Kane, Georgia Institute of Technology (United States)
Martin Strassburg, Georgia Institute of Technology (United States)
Georgia State Univ. (United States)
Ali Asghar, Georgia Institute of Technology (United States)
Qing Song, Georgia Institute of Technology (United States)
Shalini Gupta, Georgia Institute of Technology (United States)
Jayantha Senawiratne, Georgia State Univ. (United States)
Christoph Hums, Georgia State Univ. (United States)
Technische Univ. Berlin (Germany)
Ute Haboeck, Technische Univ. Berlin (Germany)
Axel Hoffmann, Technische Univ. Berlin (Germany)
Dmitry Azamat, Technische Univ. Berlin (Germany)
Wolfgang Gehlhoff, Technische Univ. Berlin (Germany)
Nikolaus Dietz, Georgia State Univ. (United States)
Z. John Zhang, Georgia Institute of Technology (United States)
Christopher J. Summers, Georgia Institute of Technology (United States)
Ian T. Ferguson, Georgia Institute of Technology (United States)

Published in SPIE Proceedings Vol. 5732:
Quantum Sensing and Nanophotonic Devices II
Manijeh Razeghi; Gail J. Brown, Editor(s)

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