Polarized excitation luminescence of semiconductor quantum wells

A new photoluminescence excitation (PLE) spectroscopy technique for the characterization of quantum‐well structures is described. The technique, which requires a standard PLE setup modified to allow for variable control of the excitation beam polarization, provides an unusually simple and unambiguous means for distinguishing between electron‐to‐light‐hole (e‐lh) and electron‐to‐heavy‐hole (e‐hh) near‐gap excitonic optical transitions. Transition types are identified by inspection of the quotient of two PLE spectra obtained using orthogonal incident beam polarizations. In this letter we describe the experimental setup and procedure for this technique, discuss the theoretical foundation for our interpretation scheme, and present experimental results for tensile‐strained GaAs_yP_1−y‐Al_xGa_1−xAs and lattice‐matched GaAs‐Al_xGa_1−xAs quantum‐well structures.