Direct observation of doping incorporation pathways in self-catalytic GaMnAs nanowires
Journal article, 2015
Doping mechanisms of Mn in GaAs nanowires (NWs) that have been grown self-catalytically at 600 degrees C by molecular beam epitaxy (MBE) are investigated using advanced electron microscopy techniques and atom probe tomography, Mn is found to be incorporated primarily in the form of non-magnetic tetragonal Ga0.82Mn0.18 nanocrystals in Ga catalyst droplets at the ends of the NWs, while trace amounts of Mn (22 +/- 4 at. ppm) are also distributed randomly in the NW bodies without forming clusters or precipitates. The nanocrystals are likely to form after switching off the reaction in the MBE chamber, since they are partially embedded in neck regions of the NWs. The Ga0.82Mn0.18 nanocrystals and the low Mn concentration in the NW bodies are insufficient to induce a ferromagnetic phase transition, suggesting that it is difficult to have high Mn contents in GaAs even in 1-D NW growth via the vapor-liquid-solid process.
Author
T. Kasama
Technical University of Denmark (DTU)
Mattias Thuvander
Chalmers, Applied Physics, Materials Microstructure
A. Siusys
Polish Academy of Sciences
L. C. Gontard
Spanish National Research Council (CSIC)
A. Kovacs
Jülich Research Centre
S. Yazdi
Technical University of Denmark (DTU)
M. Duchamp
Jülich Research Centre
A. Gustafsson
Lund University
R. E. Dunin-Borkowski
Jülich Research Centre
J. Sadowski
Lund University
Polish Academy of Sciences
Journal of Applied Physics
0021-8979 (ISSN) 1089-7550 (eISSN)
Vol. 118 5 054302Enabling Science and Technology through European Electron Microscopy (ESTEEM 2)
European Commission (EC) (EC/FP7/312483), 2012-10-01 -- 2016-09-30.
Subject Categories (SSIF 2011)
Nano Technology
DOI
10.1063/1.4927623