Piezomodulated-reflectivity study of GaAs/Al_0.29Ga_0.71As single quantum well

We report here that we have built a set of piezomodulated-reflectivity measurement system, and obtained piezomodulated-reflectivity spectra of two GaAs/Al_0.29GA_0.71 As single quantum well samples in which the well widths are 5 and 25 nm respectively. From these spectra, the transitions between electron and heavy and light hole subbands can be easily identified. Furthermore, we have observed the optical transition related to spin-orbit split-off of GaAs buffer. Effective mass theory is applied to calculate the transition energy between electron and hole subbands. Then the spectral structures are assigned based on the calculated results. It is found that these calculated results agree with experimental ones very well.