Differential Reflectance Spectroscopy of GaAs/AlGaAs Multiple Quantum Wells\+*

An improved spatial modulation technique called Differential Reflectance (DR) spectroscopy has been described. The DR spectra of GaAs/Al 0 25 Ga 0 75 As multiple quantum wells (MQWs) samples were measured experimentally. The reflectance and photoreflectance spectra of these samples were also obtained. Good correspondence between DR, PR spectra and the calculated results shows that like PR, DR technique can be used as an effective tool of the study and characterization of semiconductor quantum wells. Besides, it's proved experimentally that the DR spectra of MQWs have a first order derivative line shape of reflectance to the photon energy.