Internal transitions of confined neutral magnetoexcitons in GaAs/AlxGa1-xAs quantum wells

Optically detected resonance spectroscopy has been used to study resonant a bsorption of electrons, holes, and their complexes in GaAs/AlxGa1-xAs quant um wells (QW's) in magnetic fields up to 15 T. In undoped multiple-QW sampl es with well widths of 12.5, 15, and 20 nm, in addition to an electron and two hole cyclotron resonances, 1s --> np(+.-) (in the hydrogenic notation) internal exciton transitions (IET's) arising from two distinct neutral heav y-hole magneto-excitons were observed. The unique capability of observing e lectron and hole cyclotron resonance as well as several IET's in a single s ample permitted verification of a predicted relationship resulting from the symmetry of the magnetoexciton Hamiltonian, namely, h(omega(e) - omega(h)) = E1s-np+ - E1s-np-, where omega(e)(omega(h)) is the electron (hole) cyclo tron frequency, and E1s-np+ (E1s-np-) is the energy of the 1s --> np(+) (1s --> np(-)) transition.