Open AccessUltrafast carrier dynamics in CdTe/CdS Core/Shell quantum dots
Author(s) -
Xia Li,
Feng Dong-Hai,
Hongxuan He,
Jia Tian-Qing,
Shan Lu-Fan,
Sun Zhen-Rong,
Zhizhan Xu
Publication year - 2012
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.61.197801
Subject(s) - quantum dot , exciton , materials science , femtosecond , relaxation (psychology) , cadmium telluride photovoltaics , photoluminescence , ultrafast laser spectroscopy , charge carrier , spectroscopy , biexciton , absorption (acoustics) , ultrashort pulse , shell (structure) , chemical physics , molecular physics , condensed matter physics , optoelectronics , physics , optics , laser , quantum mechanics , composite material , psychology , social psychology
On the basic of the synthesis of CdTe/CdS core/shell quantum dots (QDs) in aqueous phase, we study ultrafast carrier dynamic behaviors of CdTe/CdS QDs with different shell thicknesses, by using femtosecond time-resolved transmission spectroscopy. The results show that both the buildup time of the lowest exciton state and its following relaxation time become longer as CdS shell thickness increases. The results also indicate that the buildup rate of a space-separate exciton is slower than that of a space-overlapped exciton, and that carrier relaxation changes from surface-defect related mechanism into surface-passivated charge separation regime, which is consistent with steady-state absorption and photoluminescence experiments.