| Autor: |
Höglund, Linda, Karlsson, Fredrik, Holtz, Per-Olof, Pettersson, Håkan, Pistol, Mats-Erik, Wang, Qin, Almqvist, Susanne, Asplund, Carl, Malm, Hedda, Petrini, Erik, Andersson, Jan |
| Jazyk: |
angličtina |
| Rok vydání: |
2010 |
| Předmět: |
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| Popis: |
A thorough investigation of quantum-dots-in-a-well structures for infrared photodetector applications has been performed employing different experimental techniques. The electronic structure of self-assembled InAs quantum dots embedded in an In0.15Ga0.85As/GaAs quantum well (QW) was deduced from photoluminescence (PL) and PL excitation (PLE) spectroscopy. From polarization-dependent PL it was revealed that the quantum dots hold two electron energy levels and two heavy-hole levels. Tunnel capacitance spectroscopy confirmed an electron energy level separation of about 50 meV, and additionally, that the conduction-band ground state and excited state of the dots are twofold and fourfold degenerates, respectively. Intersubband photocurrent spectroscopy, combined with simultaneous interband pumping of the dots, revealed a dominant transition at 150 meV (8.5 mu m) between the ground state of the quantum dots and the excited state of the QW. Results from detailed full three-dimensional calculations of the electronic structure, including effects of composition intermixing and interdot interactions, confirm the experimentally unravelled energy level scheme of the dots and well. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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