Charge and energy transfer in double asymmetric quantum wells with quantum dots
| Autor: | G. V. Budkin, M. Eremenko, A. N. Reznitskiy |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Condensed Matter::Quantum Gases
010302 applied physics Physics Condensed Matter::Other Phonon Exciton General Physics and Astronomy 02 engineering and technology Electron Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 01 natural sciences Condensed Matter::Materials Science Quantum dot 0103 physical sciences Charge carrier Atomic physics 0210 nano-technology Biexciton Quantum tunnelling Quantum well |
| Zdroj: | Journal of Experimental and Theoretical Physics. 124:740-750 |
| ISSN: | 1090-6509 1063-7761 |
| DOI: | 10.1134/s1063776117040100 |
| Popis: | The luminescence and luminescence excitation spectra of CdSe/ZnSe quantum dots are studied in a set of double quantum wells with the ZnSe barrier of width 14 nm, the same amount of a deposited CdSe layer forming a deep well and shallow wells with different depths. It is found that for a certain relation between the depths of shallow and deep wells in this set, conditions are realized under which the exciton channel in the luminescence excitation spectrum of a shallow well dominates in the region of kinetic exciton energies exceeding 10 longitudinal optical phonons above the bottom of the exciton band of the ZnSe barrier. A model is developed for the transfer of electrons, holes, and excitons between the electronic states of shallow and deep quantum wells separated by wide enough barriers. It is shown that the most probable process of electronic energy transfer between the states of shallow and deep quantum wells is indirect tunneling with the simultaneous excitation of a longitudinal optical phonon in the lattice. Because the probability of this process for single charge carriers considerably exceeds the exciton tunneling probability, a system of double quantum wells can be prepared in which, in the case of weak enough excitation, the states of quantum dots in shallow quantum wells will be mainly populated by excitons, which explains experimental results obtained. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|