1. Power density and temperature dependent multi-excited states in InAs/GaAs quantum dots
- Author
-
Hassen Maaref, Catherine Bru-Chevallier, L. Bouzaiene, L. Sfaxi, M. Baira, INL - Spectroscopies et Nanomatériaux (INL - S&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Micro-optoélectronique et Nanostructures [Monastir], Faculté des Sciences de Monastir (FSM), and Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM)
- Subjects
010302 applied physics ,Photoluminescence ,Materials science ,Exciton ,Bioengineering ,02 engineering and technology ,General Chemistry ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,7. Clean energy ,Atomic and Molecular Physics, and Optics ,Full width at half maximum ,Quantum dot ,Modeling and Simulation ,Excited state ,0103 physical sciences ,General Materials Science ,[SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics ,Atomic physics ,0210 nano-technology ,ComputingMilieux_MISCELLANEOUS ,Power density ,Molecular beam epitaxy - Abstract
Self-assembled InAs/GaAs (001) quantum dots (QDs) were grown by molecular beam epitaxy using ultra low-growth rate. A typical dot diameter of around 28 ± 2 nm and a typical height of 5 ± 1 nm are observed based on atomic force microscopy image. The photoluminescence (PL) spectra, their power and temperature dependences have been studied for ground (GS) and three excited states (1–3ES) in InAs QDs. By changing the excitation power density, we can significantly influence the distribution of excitons within the QD ensemble. The PL peak energy positions of GS and ES emissions bands depend on an excitation light power. With increasing excitation power, the GS emission energy was red-shifted, while the 1–3ES emission energies were blue-shifted. It is found that the full width at half maximum of the PL spectra has unusual relationship with increasing temperature from 9 to 300 K. The temperature dependence of QD PL spectra shown the existence of two stages of PL thermal quenching and two distinct activation energies corresponding to the temperature ranges I (9–100 K) and II (100–300 K).
- Published
- 2010