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1 PublicationAnnealing effect on ferromagnetic properties, hole concentration and electronic band structure of GaMnAs epitaxial layers
Zhu, J. J.; Li, L.; Chen, L.; Prucnal, S.; Grenzer, J.; Zhao, J. H.; Helm, M.; Zhou, S. Q.
Abstract
In this paper, we analyze the correlation of the magnetism and the carrier concentration with the shift of the spectroscopic critical points for low compensated GaMnAs samples with a high Curie temperature of around 150 K. The GaMnAs layers were grown by low-temperature molecular beam epitaxy. The low-temperature annealing leads to a reduction of Mn interstitials from 0.8 to 0.4% and an enhancement in the hole concentration. The saturation magnetization is 51 emu/cm and the Curie temperature is 150 K after post-growth annealing, while those of as-grown layers are 37 emu/cm and 80 K. The resistivity dropped significantly after the post-growth annealing, due to the fact that the number of Mn, which act as double donors and compensate holes, was significantly reduced by the low-temperature and long-time annealing. The electronic band structure is investigated by spectroscopic ellipsometry. The transition energies of critical points show redshift after post-growth annealing due to the annealing-induced enhancement of the hole concentration. Our results support the valence band picture (the Zener model) in ferromagnetic GaMnAs.
Keywords: GaMnAs; DMS; doping; magnetic properties
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
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DOI: 10.1007/s10854-017-7700-1
Cited 2 times in Scopus
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