Study on GaAs/AlGaAs multiple quantum wells irradiated by free electron laser and OTCS measurement

Photoluminescence (PL) and optical transient current spectra (OTCS) were observed from GaAs/AlGaAs quantum wells structure excited by midinfrared free electron laser (FEL) irradiation. The experimental results of PL showed that the characteristic PL peak of quantum wells shifted to longer wavelength (red shift) and the intensity decreased much after FEL irradiation. From the analysis of OTCS, extrinsic defects were found after FEL irradiation. This paper author discusses the results and comparison with that of electron irradiation．