Influence of carrier localization at the core/shell interface on the temperature dependence of the Stokes shift and the photoluminescence decay time in CdTe/CdS type-II quantum dots

Article

关键词: LIGHT-EMITTING-DIODES;    SIZE DEPENDENCE;    DARK-EXCITON;    NANOCRYSTALS;    EMISSION;    CORE;    ZNSE;    DYNAMICS;    EDGE;    GAP;   

DOI  :  10.1103/PhysRevB.96.035305

来源: SCIE

【 摘 要 】

We have systematically investigated the temperature dependence of absorption, photoluminescence (PL), and PL decay profiles in CdTe-core and CdTe/CdS type-II quantum dots (QDs). In CdTe/CdS QDs, Stokes shifts and PL decay time become larger with an increase in temperature above 120 K, while those in CdTe-core QDs are almost independent of temperature. The unusual temperature dependence of Stokes shifts and PL decay time in CdTe/CdS QDs is understood by considering carrier localization at the core/shell interface at low temperatures and thermal-energy-assisted detrapping from localized-exciton to type-II exciton states at higher temperatures. Furthermore, a phenomenological rate-equation model is developed to explain the experimentally observed temperature-dependent PL decay time.

【 授权许可】

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