Carrier dynamics in modulation-doped InAs/GaAs quantum rings

Chien Hung Lin*, Shin Chin Lin, Kien-Wen Sun, Chien Ping Lee

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Carrier dynamics in undoped and modulation-doped self-assembled InAs/GaAs quantum rings was comprehensively examined through time-resolved photoluminescence techniques at room temperature. After photoexcitation, the rates of carrier capture and relaxation in the ground state and excited states were equally fast in both the undoped and charged quantum rings. Instead of cascading down through the excited states, the carriers excited in the undoped quantum rings relaxed through the quasi-continuum states via coupling with acoustical phonons and eventually thermalized to the ground state by emitting longitudinal optical phonons. The dynamics of carrier thermalization was governed by cold carriers in the charged quantum rings. In carrier recombination, the undoped quantum rings had a shorter PL decay time and lower luminescence intensity than the charged quantum rings because radiative recombination was suppressed by defects in the matrix and the absence of cold carriers.

Original languageEnglish
Pages (from-to)24126-24131
Number of pages6
JournalRSC Advances
Issue number46
StatePublished - 14 Dec 2013


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