Free-to-bound and light- and heavy-hole bound-exciton transitions in ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As-GaAs multiple quantum wells

Observation of several optical transitions associated with the recombination of a free heavy hole with a neutral donor (${\mathit{D}}^0$,HH) and with heavy- and light-hole excitons bound to shallow donors and acceptors in a GaAs-${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As multiple-quantum-well (MQW) structure with a nominal well width of 350 Å is reported. These transitions are identified using high-resolution photoluminescence and photoluminescence excitation spectroscopies at 2 K. Temperature-dependent (2–20 K) data are also analyzed. To further aid in identifying these transitions, their behavior in the presence of a magnetic field applied parallel to the plane of the MQW structure is investigated. The measured diamagnetic shift agrees well with the calculated diamagnetic shift for the same size well.