Photoluminescence Excitation Spectroscopy of In 0.53 Ga 0.47 As/InP Multi-Quantum-Well Heterostructures

The photoluminescence and, for the first time, the excitation spectra of In 0.53 Ga 0.47 As/InP multi-quantum-well structures were measured at 4.2 K. Emission bands were observed below E 1h as well as at E 1h , where E 1h denotes the n = 1 electron-heavy-hole free-exciton transition. The emission below E 1h was found from the excitation spectra to be in striking contrast to the band-acceptor transition in thick In 0.53 Ga 0.47 As layers. Its luminescent intensity decreases very slowly or show little decrease as the photon energy of excitation decreases below E 1h . This emission is believed to be related to the n = 1 electron quantum state-acceptor transition. Fluctuation of quantum levels due to strain in the interdiffused layers at the heterointerfaces is thought to be a possible origin of the anomalous excitation spectra.