Growth of InAs Quantum Dots on InP Substrates Based on MOCVD Technology: Study on the Influence of InAlGaAs Capping Layer Thickness on Luminescent Properties and Band Structure Engineering

Self-assembled InAs quantum dots (QDs) with InAlGaAs capping layers were grown by metal–organic chemical vapor deposition (MOCVD) on N-type InP(001) substrates using an In-flush technique. By variation of the capping layer thickness below the average QD height, the photoluminescence wavelength was continuously tuned from 1420 to 1800 nm. This redshift is qualitatively attributed to the combined effects of modified quantum confinement, strain accumulation, and carrier redistribution, rather than a single dominant mechanism. The results demonstrate a viable approach for the band engineering of QDs in the key optical communication band and provide a foundation for developing high-performance optoelectronic devices.