Effect of InAs insertion layer on the structural and optical property improvement of InGaAs/InAlAs multiple quantum wells

A 100 periods In_0.53Ga_0.47As/In_0.52Al_0.48As multiple quantum wells (MQWs) with and without 2 ML InAs insertion layers (ISLs) were grown on semi-insulating GaAs (001) substrates by molecular beam epitaxy (MBE). The stress-strain was weakened by inserting two monolayers of InAs between the In_0.53Ga_0.47As well layer and the In_0.52Al_0.48As barrier layer. High-resolution transmission electron microscopy (HRTEM) was investigated to visually characterize the crystal quality of MQW structures with and without InAs ISLs. The effect of structural and optical properties of the In_0.53Ga_0.47As/In_0.52Al_0.48As MQWs by InAs-inserting were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectra. The research shows that the introduction of the 2 ML InAs ISLs can eliminate the strain and reduce the average dislocation density from 2.4×10⁸ cm⁻² to 1.4×10⁸ cm⁻² in the InGaAs/InAlAs MQWs structure, then control the interface between InGaAs and InAlAs, and finally realize the improvement of the quantum well structural and optical properties with the PL intensity increased by one order of magnitude. Our studies have great significance to the fabrication of GaAs-based multiple quantum well optoelectronic devices, which promote the further development of high-performance versatile optoelectronic applications.