Direct experimental evidence of indirect bandgap transitions in strained GaInAs(P)/InP quantum well structures

An additional low energy peak was found in low temperature photoluminescence of tensile strained GaInAs/InP quantum well structures. Owing to the tensile strain, the uppermost valence band state is shifted out of the Brillouin zone center thus giving rise to the formation of an indirect band structure. In consequence, the low energy peak was attributed to a phonon assisted transition of an indirect exciton. Carrier lifetime measurements confirm this interpretation.<
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