Mechanism of photo-induced strain relaxation in Sb₂S₃-coated quantum-dot nanowires

Determine the physical mechanisms responsible for the photo-induced strain relaxation and consequent spectral tuning in InP/InAs quantum-dot nanowires coated with amorphous Sb₂S₃ and SiO₂.

Background

The paper demonstrates persistent, laser-induced redshifts of the emission from InAs quantum dots embedded in InP nanowires coated with an amorphous Sb₂S₃ shell. Photoluminescence, X-ray diffraction, and microscopy measurements support an interpretation based on partial relaxation of the compressive strain imposed by the shell.

The observed tuning cannot be explained by conventional laser-induced crystallization under the reported 671 nm irradiation conditions: the authors observe no sufficient heating or crystallization and therefore discuss alternative chalcogenide-glass processes, including photo-induced bond rearrangements, photostructural relaxation, and local atomic reconfiguration. However, the specific physical mechanism that connects optical excitation, stored elastic energy, structural rearrangement in amorphous Sb₂S₃, and strain relaxation in the nanowire remains unresolved.