Improving optical properties of 1.55 μm GaInNAs/GaAs multiple quantum wells with Ga(In)NAs barrier and space layer

We present the 1.55 μm GaInNAs/GaAs multiple quantum well (QW) heterostructures with a GaNAs or a GaInNAs barrier and space layer (BSL). The stronger improvement of photoluminescence efficiency has been observed with increasing N concentration in a GaNAs BSL, instead of increasing N composition in GaInNAs QWs, to achieve room-temperature emission above 1.5 μm for GaInNAs/GaNAs multiple QW structure, when the nitrogen concentration in GaInNAs QW is as high as 3%. A further enhancement of photoluminescence intensity and a remarkable reduction of emission linewidth of GaInNAs multiple QWs have been demonstrated by using a GaInNAs quaternary BSL. These effects of a GaInNAs BSL could be understood in terms of the improvement of structural properties of GaInNAs QWs, resulting from the reduction of the strain at QW/BSL interface. These results present a variable approach to further developing GaAs-based light sources in the telecommunication-wavelength range near 1.55 μm.