A new type of spacial modulation spectroscopy applied in semiconductor superlattices quantum wells

A new type of differential reflectance (DR) spectroscopy technique that rel ies on the spacial modulation by rotation was reported. The experimental re sults in GaAs/AlGaAs and strained InGaAs/GaAs multiple quantum wells by usi ng DR technique at room temperature were presented, and compared with the e xperimental results of photoreflectance (PR) spectra and the theoretical va lues. It is shown that both spectra of DR and PR are coincident and in good agreement with the theoretically predicted values. The modulation signal o f DR spectra (Delta R/R) is about 10(-2), which is much higher than that in PR measurements. It is concluded that DR is an effective method at room te mperature for the study of films, semiconductor superlattices and quantum w ells.