Tuning the emission wavelength by varying the Sb composition in InGaAs/GaAsSb "W" quantum wells grown on GaAs (001) substrates

InGaAs/GaAsSb "W" quantum wells with GaAsP barriers are grown on GaAs (001) substrates by molecular beam epitaxy. We investigate the effect of the Sb composition in GaAsSb on the photoluminescence (PL) wavelength. X-ray rocking curve (XRC) measurements and simulations are performed to investigate the material composition and layer thickness. Low-temperature PL spectra are consistent with the XRC results. At the lowest Sb composition of 6%, the PL intensity is the strongest, and room-temperature PL is realized at similar to 1100 nm. By increasing the Sb composition in the GaAsSb layer, low-temperature (20 K) PL emits at longer wavelength up to similar to 1400 nm at 21% Sb while the PL intensity is the weakest. The XRC is also degraded. The strained bandgap simulation reveals the type-I to type-II band alignment transition as the Sb composition is >= 9%.