Browsing by Author "Su, S. K."

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Shape dependent carrier dynamics in InAs/GaAs nanostructures
(2009-12-01)
Lin, C. H.
;
Ling, H. S.
;
Su, S. K.
;
Lin, S. D.
;
Lee, C. P.
We present systematic experimental studies of the temperature dependence of continuous wave and time-resolved photoluminescence spectroscopy in self-assembled InAs/GaAs nanostructures as the shape of quantum structures evolved from dot to ring. The carrier dynamics show strong dependence on the geometrical shape of the nanostructures under investigation. An increase in photoluminescence decay time of the excited and ground states is observed as the shape of nanostructures changed from dot, volcano, to ring. It is attributed to the carrier thermalization between the dark and ground states. The photoluminescence excitation spectra of the quantum rings reveal resonances related to the dark states. A rate equation model is proposed to interpret the observed carrier dynamics.
Temperature dependence of time-resolved photoluminescence spectroscopy in InAs/GaAs quantum ring
(2009-05-04)
Lin, C. H.
;
Lin, H. S.
;
Huang, C. C.
;
Su, S. K.
;
Lin, S. D.
We present detailed experimental results of the temperature dependence of continuous wave and time-resolved photoluminescence (PL) spectroscopy in self-assembled InAs/GaAs quantum dot and quantum ring nanostructures. A dramatic increase in PL decay time of the excited and ground states is observed in InAs quantum rings at high temperature. We speculate that the longer PL lifetime in quantum rings is due to the interplay among the dark states, ground states, and the reduced wave function overlapping between electrons and holes. A rate equation model is proposed to interpret the observed temperature dependence of the ground state exciton lifetime.