Browsing by Author "Chia, Chin-Hau"

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Radiative recombination of indirect exciton in type-II ZnSeTe/ZnSe multiple quantum wells
(2011-05-01)
Chia, Chin-Hau
;
Fan, Wen-Chung
;
Lin, Yen-Chen
;
Chou, Wu-Ching
;
電子物理學系
The tunability of the emission energy, oscillator strength and photoluminescence (PL) efficiency by varying the well thickness and excitation density was demonstrated in the ZnSe(0.8)Te(0.2)/ZnSe multiple quantum wells. A significant blueshift about 260 meV of the PL peak energy was observed as the well width decreased from 5 to 1 nm. An extraordinary long lifetime (300 ns) of the recombination for the widest sample was detected. The binding energy of the indirect excitons is determined as 12 meV for the thinnest sample. The reduction of PL efficiency by thermal energy is greatly suppressed by employing a high excitation power. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
Temperature-dependent decay dynamics in highly mismatched ZnSe1-xTex alloy
(2012-02-13)
Lin, Yan-Cheng
;
Jiang, Wei-Shi
;
Chou, Wu-Ching
;
Chen, Wei-Kuo
;
Chang, Wen-Hao
This study investigates the temperature-dependent decay dynamics in highly mismatched ZnSe0.950Te0.050 alloy using photoluminescence (PL) and time-resolved PL spectroscopy. The PL peak energy exhibits a V-shaped dependence on temperature (10-300 K), indicating strong carrier localization. Kohlrausch's stretched exponential law, in which the deduced stretching exponent beta is highly consistent with the V-shaped PL peak shift, closely corresponds to the complex decay curves over a wide temperature range. Additionally, the PL lifetime tau initially increases and then monotonically declines as the temperature increases. These findings agree excellently with the low electron-hole binding energy upon thermal ionization of weakly bound electrons. (C) 2012 American Institute of Physics. [doi:10.1063/1.3687187]