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Optical characterization of Zn 0.97 Mn 0.03 Se/ZnSe 0.92 Te 0.08 type II multiple‐quantum‐well structures
Author(s) -
Lin D. Y.,
Shiu J. J.,
Wu J. D.,
Yang C. S.,
Chou W. C.
Publication year - 2007
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200675123
Subject(s) - blueshift , photoluminescence , spectral line , polarization (electrochemistry) , band bending , excitation , quantum well , chemistry , molecular physics , analytical chemistry (journal) , materials science , condensed matter physics , optics , physics , laser , optoelectronics , quantum mechanics , astronomy , chromatography
The optical characterization of type II Zn 0.97 Mn 0.03 Se/ZnSe 0.92 Te 0.08 multiple‐quantum‐well structures have been studied using photoluminescence (PL), temperature‐dependent PL, polarized PL, power‐dependent PL, and photoreflectance (PR) in this study. The PL data reveal that the band alignment of the ZnMnSe/ZnSeTe system is type II. Comparing with the theoretical calculation based on the Schrodinger equation, the valence band offset is estimated to be 0.6 eV. From the power‐dependent PL spectra, it is observed that the peak position of PL spectra shows a blueshift under different excitation power. The blueshift can be interpreted in terms of the band‐bending effect due to spatially photoexcited carriers in a type II alignment. The thermal activation energy ( E A ) for quenching the PL intensity was determined from tem‐ perature‐dependent PL spectra. The thermal activation energy was found to decrease as the thickness of ZnMnSe and ZnSeTe layers decreased. The polarized PL spectra exhibit a large in‐plane polarization with the polarization degree up to 50%. The polarization does not depend on the excitation intensity as well as temperature. The large polarization is an inherent orientation of the interface chemical bonds. The higher transition features observed in PR spectra show a blueshift with the similar trend observed in the PL spectra as decreasing the thickness of ZnSeTe layer. This result provides a consistent evidence for the assumption that square‐like well shapes were built in the ZnSeTe layers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)