The effects of strain compensation in type-II GaAsSb/InGaAs quantum wells grown on GaAs (001) substrates

The effect of the GaAsP strain-compensating layer on type-II GaAs_1−xSb_x/In_yGa_1−yAs was investigated. GaAsSb/InGaAs multiple quantum wells (MQWs) without and with GaAsP strain-compensating layers were grown by molecular beam epitaxy. Increasing Sb or In compositions can extend photoluminescence (PL) emission at longer wavelength along with the highly induced compressive strain in the QWs. The power-dependent PL measured at low temperature reveals the type-II band characteristics of the GaAs_1−xSb_x/In_yGa_1−yAs system. A detailed analysis of the experimental data reveals that the GaAsP layers compensate the compressive strain of GaAsSb/InGaAs. The type-II QWs with GaAsP layers, (8 nm) GaAs_0.84Sb_0.16/(2.5 nm) In_0.3Ga_0.7As/(10 nm) GaAs_0.85P_0.15, emits PL at ∼1.1 μm, up to 210 K, while the PL of those strained sample without GaAsP vanishes at lower temperature. In view of the described sample, x-ray diffraction (XRD) analysis along with the simulation shows the validity of the procedure, resulting in nearly matched parameters of QW thicknesses and material compositions—(8.9 nm) GaAs_0.835Sb_0.165/(2.3 nm) In_0.3Ga_0.7As/(10.3 nm) GaAs_0.85P_0.15, with those of the designed QW. The thicknesses of QW from the TEM image, (8.6 nm) GaAsSb/(3.1 nm) InGaAs/(10.1 nm) GaAsP, agree well with the XRD results.