Picosecond dynamics of quantum structure carriers measured by time resolved photoinduced intersubband absorption
✍ Scribed by R. Duet; D. Gershoni; E. Ehrenfreund
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 225 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0749-6036
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✦ Synopsis
A novel interband-pump intersubband-probe technique is developed in order to study the dynamics of photogenerated carriers and excitons in (\mathrm{GaAs} / \mathrm{AlGaAs}) superlattices by time resolved photoinduced absorption. The photogenerated population reaches a thermal distribution a few picoseconds after the excitation. The time dependence of the intersubband absorption strength and its time resolved excitation spectra yield a measure for the time it takes for that population to cool first to the lattice temperature and then to radiatively decay. The first time is roughly (70-100) ps depending on the excess energy with which the photogenerated carriers are created. The second is on a sub-nanosecond scale and depends linearly on the lattice temperature.