In-situ photo-modulated reflectance study on GaAs/AlxGa1-xAs single surface quantum wells

We have studied the optical properties of surface quantum wells with differ ent width of wells (5nm and 10nm) by means of In-situ photo-modulated refle ctance(PR) spectroscopy on a molecular beam epitaxy system. The surface qua ntum well is confined on one side by the vacuum and on the other side by Al xGa1-xAs barrier. In experiments, we have observed clearly the transitions between the confined heavy and light hole states to the confined electron s tates. The transitions of the excited states in 10nm surface quantum well a re observed at first. The effects of the surface on the confined states hav e been well studied by combination of the PR spectra and the effective mass approximation theory.