Interplay of GaAsP barrier and strain compensation in InGaAs quantum well at near-critical thickness

•Highly strained InGaAs MQWs were grown using metalorganic vapor phase epitaxy.•Strain relaxation was studied via XRD-RSM, confirmed by AFM and micro-PL techniques.•GaAsP barrier with proper elastic energy density is essential for strain compensation in InGaAs MQW. The effect of GaAs1−yPy tensile-strained barriers on suppressing the partial strain relaxation of InGaAs/GaAs multiple quantum wells (MQWs) is investigated when the thickness of a heavily strained InxGa1−xAs QW is near-critical thickness. The strain relaxations of In0.4Ga0.6As MQWs with and without strain-compensating GaAs1−yPy barriers are characterized using X-ray diffraction reciprocal space mapping (RSM) and micro-photoluminescence (µ-PL) mapping. A significant amount of strain relaxation (~1.53%) is measured when the thickness of each In0.4Ga0.6As QW within a 4-period MQW becomes 9.5 nm in the absence of strain-compensating layers. By adding two ~5 nm GaAs0.67P0.33 tensile-strained barriers sandwiching each QW, the strain relaxation in the In0.4Ga0.6As/GaAs0.67P0.33/GaAs MQWs is reduced to ~0.3% together with decreased surface roughness. Our study shows that tensile barriers with proper elastic energy densities are essential to achieve efficient strain compensation in a heavily-strained InGaAs MQW structure, which provides an important insight into the understanding of how to better achieve the benefits of strain compensation in III-V based QWs and superlattices.