Browsing by Author "Hsu, W. L."

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Biexciton emission from sol-gel ZnMgO nanopowders
(2010-05-10)
Chia, C. H.
;
Lai, Y. J.
;
Hsu, W. L.
;
Han, T. C.
;
Chiou, J. W.
We studied the power-dependent photoluminescence of Zn(1-x)Mg(x)O nanopowders grown by sol-gel method, at temperature T = 100 K. At moderate optical pumping intensity, a nonlinear emission band due to the radiative recombination of free biexcitons was detected. We found that the free biexciton binding energies of Zn(1-x)Mg(x)O nanopowder (0.01 <= x <= 0.05) are nearly constant (13.5 +/- 1.5 meV). (C) 2010 American Institute of Physics. [doi:10.1063/1.3428780]
Size dependence of exciton-phonon coupling in sol-gel ZnMgO powders
(2011-03-15)
Chia, C. H.
;
Chen, J. N.
;
Han, T. C.
;
Chiou, J. W.
;
Lin, Y. C.
We found that the exciton-phonon coupling in the Zn(1-x)Mg(x)O powders (0.01 <= x <= 0.07) is greatly influenced by the crystalline-size. Two well-resolved photoluminescence (PL) bands due to recombination of free exciton and its longitudinal optical (LO)-phonon replicas enable us to analyze the relative intensities among free excitons, one-LO-phonon replicas, and two-LO-phonon replicas. As crystalline size increases, a larger enhancement of the PL-intensity ratio of a free exciton to its LO-phonon replicas was found compared to that of two LO-phonon replica to one-LO-phonon replica. (C) 2011 American Institute of Physics. [doi:10.1063/1.3563574]
Thermal-activated carrier transfer in ZnCdO thin film grown by plasma-assisted molecular beam epitaxy
(2013-09-01)
Chien, K. F.
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Hsu, W. L.
;
Tzou, A. J. .
;
Lin, Y. C.
;
Chou, W. C.
` The thermal-activated carrier transfer processes in a Zn0.98Cd0.020 thin film grown by plasma-assisted molecular beam epitaxy were investigated using temperature-dependent and time-resolved photoluminescence (PL) spectroscopy. As the temperature increases from 50 to 220 K, the carriers transfer from shallow to deep localized states. Additionally, the carriers escape from the deep localized states above 220 K due to an activation energy of about 19 meV. (c) 2013 Elsevier B.V. All rights reserved.