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Monitoring the α‐ to β‐phase transition in MnAs/GaAs(001) thin films as function of temperature
Author(s) -
Gallas B.,
Rivory J.,
Arwin H.,
Vidal F.,
Stchakovsky M.
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200777783
Subject(s) - epitaxy , condensed matter physics , amorphous solid , anisotropy , materials science , thin film , atmospheric temperature range , phase transition , phase (matter) , dielectric , dielectric function , layer (electronics) , analytical chemistry (journal) , chemistry , optics , crystallography , optoelectronics , nanotechnology , physics , thermodynamics , organic chemistry , chromatography
MnAs layers with a 5 nm thick amorphous GaAs capping layer were grown epitaxially on GaAs(001). Generalized ellipsometric measurements were made on a 45 nm thick layer in the spectral range 1.5–4 eV at temperatures between –10 °C and 50 °C in steps of 5 °C. By using both the diagonal and off‐diagonal elements of the Jones matrix, the in‐plane unixial anisotropy of MnAs was determined in terms of the ordinary and extraordinary complex dielectric functions. The measurements at each temperature could be well reproduced by modeling using the optical properties of the two limiting phases α‐MnAs and β‐MnAs determined at –10 °C and 50 °C, respectively. The best sensitivity to the volume fractions of the two phases was obtained near 2.2 eV by monitoring the generalized ellipsometric parameter Δ p for which the variations reached 30°. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)