SUPPRESSION OF DIRECT-TRANSITION PHONON SIDE BANDS IN THE MAGNETOLUMINESCENCE FROM DOPED QUANTUM-WELLS

We present a theory for and the observation of LO-phonon side bands fo r transitions between the electron and hole Landau levels (n(e), n(h) = 0, 1,...). The side band of the primary n(e) = 0 --> n(h) = 0 line i n an n-GaAs/InGaAs/AlGaAs quantum well is absent at low temperatures. The side bands of the secondary n(e) (>0) --> n(h) = 0 lines are relat ively strong, growing with n(e) in excellent agreement with the theory . The suppression of small-Delta n (=\n(e) - n(h)\) side bands is due to the interference between the electron-phonon and hole-phonon recomb ination channels and the magnetic quantization in two dimensions.