We have studied narrow multiple quantum-well (MQW) wires using conventional absorption spectroscopy and time-resolved absorption measurements. Wires down to 130 nm were fabricated from MQW's using focused ion-beam lithography and electron cyclotron-resonance chlorine-plasma etching. In this structure, the photoexcited carriers diffuse toward sidewalls and recombine on the sidewall surface. We confirmed from the absorption spectrum of MQW wires that the exciton peak is preserved even in wires 130 nm wide. We show that the excitonic absorption recovery of MQW wires is reduced to 11 ps, preserving excitonic optical nonlinearity.
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