Захват и рекомбинация носителей в полупроводниковых квантовых точках CdSe/ZnSeстатья
Статья опубликована в журнале из списка RSCI Web of Science
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Статья опубликована в журнале из перечня ВАК
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 20 сентября 2013 г.
Аннотация:Time-resolved photoluminescence (PL) spectra of self-assembled CdSe/ZnSe quantum dots (QDs) are measured with a view to identifying the QD-size dependence of carrier capture and recombination in a single QD. The PL is excited by optical absorption in the ZnSe barrier layers under weak and strong irradiation with femto-and nanosecond laser pulses, respectively. In the case of weak excitation, the PL dynamics observed in a QD and the barrier layers are attributed to (i) fast carrier diffusion in the barrier layers, (ii) intense capture of carriers by the QD, (iii) fast carrier relaxation to the QD ground state, and (iv) dependence of the carrier capture and recombination times on the QD size. In the case of strong excitation, PL spectra are measured for different levels of excitation intensity and PL intensity is examined as a function of excitation intensity. It is established that (i) an increase in excitation intensity has a stronger effect on a high-frequency part of the spectrum and (ii) the intensity characteristic is essentially nonlinear. These findings are explained by state filling and/or decrease in carrier capture rate as the QD becomes increasingly full.