Measurement of miniband parameters of a doped superlattice by photoluminescence in high magnetic fields

We have studied a 50/50 A superlattice of GaAs/Al0.21Ga0.79As composition, modulation-doped with Si, to produce n = 1.4 × 1012 cm−2 electrons per superlattice period. The modulation-doping was tailored to avoid the formation of Tamm states, and photoluminescence (PL) due to interband transitions from extended superlattice states was detected. By studying the effects of a quantizing magnetic field on the superlattice PL, the miniband energy width, the reduced effective mass of the electron–hole pair, and the band gap renormalization could be deduced.