Spectroscopy studies of P-type GaAs/AlGaAs MQWs heavily doped with carbon

摘要

In the low-temperature eflectance spectra of GaAs/AlGaAs MQW structures heavily doped in the wells with carbon, a series of resonances with energies below the barrier gap were observed. Taking into account the high doping levels of up to 5x10~(19) cm~(3-), detailed computations which include Hartree and exchange-correlation effects were carried out to obtain the effective MQW potential, the electron and hole energy eigenvalues and the Fermi level. On the basis of these calculations the resonances are well explained by excitonic transitions between the second hole and second electron subbands. It is shown that the band gap narrowing effect for p-type doped QWs has a similar magnitude to that in bulk GaAs.