Internal transitions of excitons and hole cyclotron resonance in undoped GaAs/AlGaAs quantum wells by optically detected resonance spectroscopy

Optically detected resonance (ODR) spectroscopy has been used to study electron and hole cyclotron resonance (CR) and various internal excitonic transitions in one sample in magnetic fields up to 15 T. The consequences of the cylindrical symmetry of the Hamiltonian for this system are observed directly. The energy difference between electron and hole CR equals the energy difference between any pair of 1s → np_± internal excitonic transitions (IET). The two principal hole CR transitions were identified from comparison with theoretical calculations. In addition to the nearly degenerate 1s → 2p₊ IET(s), two 1s → 2p_- IETs resulting from the two distinct heavy-hole magnetoexcitons were observed. The capability of observing electron and hole CR as well as several IETs in a single sample is unique to the ODR technique and demonstrates its potential for elucidating the electronic states of semiconductor nanostructures.