InAs/InGaAs quantum dots with room temperature photoluminescence at 1380 nm by Sb surfactant-induced strain relaxation

This study examined the effects of Sb exposure on the optical properties of InAs/InGaAs quantum dot-in-a-well (QDWELL) heterostructures. A two-step strain compensation scheme was employed, with InAs QDs embedded within an InGaAs matrix to reduce the compressive strain caused by lattice mismatch between InAs and GaAs. Subsequent post-growth Sb flux exposure further reduced strain and altered surface energetics, producing a pronounced redshift of the ground-state emission from 1310 to 1380 nm at room temperature with a narrow linewidth (<30 meV). Temperature-dependent photoluminescence measurements also showed an enhanced activation energy of approximately 288 meV, compared with 250 meV for the QDs without Sb exposure, indicating a deeper confinement potential arising from increased conduction and valence band offsets. These results suggest that this approach allows both strain and carrier confinement to be effectively tailored to enable wavelength tuning into the E-band, promising for QD-based long-wavelength optoelectronic devices.