Abstract
The relaxation mechanisms of an array of 10 vertically coupled layers of InGaAs/AlGaAs quantum dots were studied by time-resolved photoluminescencc. Both resonant and non-resonant excitation were employed and the photoluminescence (PL) intensity in the non-resonant case is a factor of 200 larger than the intensity with resonant excitation. The results obtained in the non-resonant pumping experiment were analysed with a rate equation model. It was found that the PL decay time increases rapidly with the wavelength of detection. Large carrier capture cross-sections [(2.5±0.9) × 10-5 cm3/s] were deduced, resulting in a capture time of 1 ps for a carrier concentration of 4 × 1016cm-3. A very fast PL risetime was observed with resonant pumping, ruling out a phonon bottleneck effect in these samples. The decay times at a given wavelength are always shorter for resonant than for non-resonant excitation and their difference increases rapidly with wavelength. This is interpreted in terms of a state filling effect for the non-resonant case. © 1999 Publication Board, Japanese Journal of Applied Physics.
Original language | English |
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Pages (from-to) | 674-680 |
Number of pages | 7 |
Journal | Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers |
Volume | 38 |
Issue number | 2 A |
Publication status | Published - 1999 |
Keywords
- Carrier dynamics
- Diode lasers
- III-V semiconductors
- Photoluminescence
- Quantum dots