Browsing by Author "Kuo, M. C."

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Effects of substrate temperature on properties of Alq3 amorphous layers prepared by vacuum deposition
(2006-01-01)
Chiu, K. C.
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Jian, Z. A.
;
Luo, Y. Z.
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Chung, J. M.
;
Tang, S. J.
In this report, various organic Alq3 amorphous layers are prepared by vacuum deposition at different substrate temperatures T-sub (from 30 to 180 degrees C). The surface morphology, structural information, electrical and optical properties of these as-deposited layers are investigated by atomic force microscopy, X-ray diffraction, J-E curves, and photoluminescence studies, respectively. Furthermore, a temperature dependence of dark electrical conductivity sigma(T) deduced from J-E curves of these organic amorphous layers is presented. Finally, effects from T-sub on the physical properties of these organic Alq3 amorphous layers are discussed and a model based on a thermal interconversion between Alq3 isomers is proposed to explain these experimental results.
Photoluminescence studies of type-II diluted magnetic semiconductor ZnMnTe/ZnSe quantum dots
(2006-12-25)
Kuo, M. C.
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Hsu, J. S.
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Shen, J. L.
;
Chiu, K. C.
;
Fan, W. C.
Type-II diluted magnetic semiconductor ZnMnTe quantum dots (QDs) in ZnSe matrix grown by molecular beam epitaxy were investigated by conventional and magnetophotoluminescence (PL) spectroscopy. The QD emission exhibits a type-II characteristic in excitation power dependence of PL peak energy. A nonzero circular polarization of PL at the absence of magnetic field was observed. This phenomenon is attributed to the accumulation of interface charges confined in adjacent layers. The magneto-optical measurement demonstrates a magnetic-induced degree of circular polarization in the PL spectra, indicating the Mn incorporation into the QD system. (c) 2006 American Institute of Physics.