Published online by Cambridge University Press: 28 February 2011
Photoluminescence and photoluminescence excitation spectroscopies are utilized to study excitons in GaAs/AlGaAs quantum wells (QW's) fabricated using MBE on MOCVD grown GaAs/Si. The experimental results are understood in terms of the biaxial tension of approximately 3 kbar present in the plane of growth for both the QW's and the GaAs buffer. An important consequence of the biaxial tension is that for QW's with well widths larger than ≈15 nm the light- and heavy- hole sub-bands cross each other in energy. This results in the light-hole exciton energy being lower than that of the heavy-hole exciton, opposite to the case of QW's grown on GaAs substrates.