COMBINED EXCITON-CYCLOTRON RESONANCE IN QUANTUM-WELL STRUCTURES

A combined exciton-cyclotron resonance is found in photoluminescence e xcitation and reflectivity spectra of semiconductor quantum wells cont aining an electron gas of low density. In external magnetic fields, an incident photon creates an exciton in the ground state and simultaneo usly excites one of the resident electrons from the lowest to one of t he upper Landau levels. A theoretical model is developed, which gives a good quantitative description of the energy position and the intensi ty of the combined exciton-cyclotron resonance.