Photoluminescence Excitation Spectroscopy of Strained Ingaas/GaAs Quantum Wells

Photoluminescence excitation spectroscopy of exciton transitions has been utilized to obtain information about light-holes in strained InGaAs/GaAs single quantum wells. By monitoring their behavior with respect to that of heavy-holes, it was shown possible to ascertain whether or not the quantum wells were pseudomorphic (lattice matched but strained) or relaxed and, if strained, the magnitude of strain present. Thus the indium composition of the single QW layers was deduced. This method is advantageous since it is nondestructive, requires no special sample preparation, is accurate and can readily be extended to monitoring strain in QWs subjected to various processing steps associated with device fabrication.