https://scholars.lib.ntu.edu.tw/handle/123456789/626344
Title: | Recombination dynamics in CdTe/CdSe type-II quantum dots | Authors: | Wang C.H Chen T.T Chen Y.F Ho M.L Lai C.W YANG-FANG CHEN |
Issue Date: | 2008 | Journal Volume: | 19 | Journal Issue: | 11 | Source: | Nanotechnology | Abstract: | Recombination dynamics in CdTe/CdSe core-shell type-II quantum dots (QDs) has been investigated by time-resolved photoluminescence (PL) spectroscopy. A very long PL decay time of several hundred nanoseconds has been found at low temperature, which can be rationalized by the spatially separated electrons and holes occurring in a type-II heterostructure. For the temperature dependence of the radiative lifetime, the linewidth and the peak energy of PL spectra show that the recombination of carriers is dominated by delocalized excitons at temperatures below 150 K, while the mixture of delocalized excitons, electrons and holes overwhelms the process at higher temperature. The binding energy of delocalized excitons obtained from the temperature dependence of the non-radiative lifetime is consistent with the theoretical value. The energy dependence of lifetime measurements reveals a third power relationship between the radiative lifetime and the radius of QDs, the light of which can be shed by the quantum confinement effect. In addition, the radiative decay rate is found to be proportional to the square root of excitation power, arising from the change of wavefunction overlap of electrons and holes due to the band bending effect, which is an inherent character of a type-II band alignment. © IOP Publishing Ltd. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-42549084773&doi=10.1088%2f0957-4484%2f19%2f11%2f115702&partnerID=40&md5=005599d435d9aee24dee504452a79d21 https://scholars.lib.ntu.edu.tw/handle/123456789/626344 |
ISSN: | 09574484 | DOI: | 10.1088/0957-4484/19/11/115702 | SDG/Keyword: | Carrier lifetime; Excitons; Low temperature effects; Photoluminescence spectroscopy; Semiconducting cadmium compounds; Delocalized excitons; Lifetime measurements; Recombination dynamics; Semiconductor quantum dots; cadmium; quantum dot; selenium; tellurium; article; electron transport; energy transfer; excitation; molecular dynamics; photoluminescence; priority journal; spectroscopy; temperature dependence |
Appears in Collections: | 化學系 |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.