Photogenerated charge effects on photoluminescence signals in a GaAs/AlAs superlattice p-i-n diode with thicker barriers

Electric field effects on photoluminescence spectra have been investigated of a p-i-n diode whose intrinsic layer consists of a 100-period GaAs/AlAs superlattice as a function of illumination power. The PL spectral characteristics show unusual behaviors, which are strongly deviated from those expected from the quantum-confined Stark effect. That is, low-energy PL peaks or shoulders are observed in addition to the main PL peak due to the ground subband state under the reverse bias conditions. The PL changes with the reverse bias voltage are strongly dependent on the illumination power. These anomalous PL results indicate that the electric field domains can be formed for a certain low excitation power, suggesting that the carrier transport within the intrinsic layer of the diode is strongly influenced by photogenerated space charges.