PHOTOREFLECTANCE STUDIES OF LATTICE-MATCHED AND STRAINED INGAAS INALAS SINGLE QUANTUM-WELLS

Lattice-matched and strained InxGa1-xAs/In0.52Al0.48As single quantum wells with x=0.53 and x=0.60 have been studied by the optical modulati on technique of photoreflectance (PR) at room temperature. The measure ments have allowed the observation of interband transitions from the h eavy- and light-hole valence subbands to the conduction subbands. The PR data have been adjusted with a least-squares fit to the first-deriv ative functional form. The energetic positions of the optical transiti ons deduced from the fit have been compared with theoretical values ob tained by an envelope function model calculation including strain effe cts. The best adjustment allowed the determination of the conduction-b and offset parameter Q(c) which is found equal to 0.71 +/- 0.07 for th e lattice-matched and strained compositions.