Optical properties and band bending of InGaAs/GaAsBi/InGaAs type-Ⅱ quantum well grown by gas source molecular beam epitaxy

摘要

Photoluminescence (PL) properties of In_(0.2)Ga_(0.8)As/GaAs_(0.96)Bi_(0.04)/In_(0.2)Ga_(0.8)As quantum well (QW) grown on GaAs substrates by gas source molecular beam epitaxy were studied by varying excitation power and temperature, respectively. The type-Ⅱ transition energy shifts from 1.149eV to 1.192 eV when increasing the excitation power from 10 mW to 150 mW at 4.5 K, which was ascribed to the band-bending effect. On the other hand, the type-Ⅱ PL quenches quickly along with fast redshift with the increasing temperature due to the relaxation of the band bending caused by the thermal excitation process. An 8 band k·p model was used to analyze the electronic properties and the band-bending effect in the type-Ⅱ QW. The calculated subband levels and transition energy fit well with the experiment results, and two thermal activation energies of 8.7 meV and 50meV, respectively, are deduced.