Full-spectrumopticallydetectedresonance(ODR)spectroscopy ofGaAs=AlGaAsquantumwells 1

Resonant magneto-absorption of far-infrared (FIR) laser radiation by neutral and negatively charged donors and free electrons, and the mechanisms of coupling of the power absorbed to various photoluminescence recombination paths in a Si-doped GaAs=AlGaAs multiple-quantum-well structure was studied by optically detected resonance (ODR) spectroscopy. A sensitive charge-coupled-device detection scheme was used to record complete PL=ODR spectra at high resolution with good signal-to-noise. The rich and complex ODR spectra were analyzed by a line-tting procedure. Results on the neutral donor 1s{2p+ transition show that at low FIR laster intensities, the recombination is modied by processes that do not involve carrier heating. At high FIR laser intensities, carrier heating eects dominate. ? 1998 Published by Elsevier Science B.V. All rights reserved.