Spectroscopy of sub-wetting layer states in InAs/GaAs quantum dot bi-layer systems
| Autor: | Yu. I. Mazur, Zh. M. Wang, M. P. Lisitsa, Georgiy G. Tarasov, Gregory J. Salamo, Z. Ya. Zhuchenko, H Kissel |
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| Rok vydání: | 2006 |
| Předmět: |
Photoluminescence
Condensed matter physics Chemistry Band gap Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Condensed Matter Physics Electronic Optical and Magnetic Materials Condensed Matter::Materials Science Quantum dot Monolayer Materials Chemistry Density of states Electrical and Electronic Engineering Spectroscopy Excitation Wetting layer |
| Zdroj: | Semiconductor Science and Technology. 22:86-96 |
| ISSN: | 1361-6641 0268-1242 |
| Popis: | The density of states for InAs/GaAs quantum dot (QDs) bi-layer arrays placed between two AlGaAs barriers is studied by means of photoluminescence (PL) excitation, resonant PL and time-resolved PL. By varying the excitation energy from above the AlGaAs band gap to values resonant with the QD energies, the energy of states in each layer including the wetting layer, corresponding localized states, defect states and QD states is determined. The creation of asymmetric pairs of quantum dots caused by interlayer coupling is traced starting from the case of weakly correlated systems represented by bi-layer QD arrays with a thick GaAs spacer layer (50 monolayers) to the case of fully correlated systems with a GaAs spacer (30 monolayers). Different mechanisms of carrier relaxation related to the density of states below the barrier and interlayer coupling are explored. |
| Databáze: | OpenAIRE |
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