Low-density band-filling in strained InAs quantum wells

We study the low-temperature photoluminescence (PL) of strained InAs single quantum wells (SQWs) embedded in a Ga_0.47In_0.53As matrix grown on InP substrates by modified solid-source molecular beam epitaxy. The spectra are interpreted in the frame of a two-level rate equation model describing the carrier dynamics in the structures. We show that band-filling occurs in these QWs for an excitation power as low as 30 Wcm^–2. Moreover, the spectra reveal that the band-filling results from the rapid population of the hole subband. This observation highlights the low in-plane heavy-hole mass in the compressively strained film. Our results therefore demonstrate the high potential of InAs/Ga_0.47In_0.53As QW nonlinear optical devices operating in the mid-IR wavelength range.