Abstract
The intersubband absorption spectrum of hot electrons is studied in a As/As multiple-quantum-well structure by picosecond infrared spectroscopy. The bandwidth of the transition between the n=1 and n=2 conduction subbands increases from 7 to 13 meV for a rise of the transient carrier temperature from 10 to 350 K. This broadening relaxes with carrier cooling on a time scale of approximately 100 ps. The different dispersion of the two subbands and the broad distribution function of hot electrons result in a temperature-dependent bandwidth of the spectrum. Theoretical calculations account quantitatively for our data.
- Received 7 July 1989
DOI:https://doi.org/10.1103/PhysRevB.40.10002
©1989 American Physical Society