Amplified Spontaneous Emission and Lasing from Zn-Processed AgIn5S8 Core/Shell Quantum Dots

I-III-VI ternary quantum dots (QDs) have emerged as favorable alternatives to the toxic II-VI QDs for optoelectronic and biological applications. However, their use as optical gain media for microlasers is still limited by a low neous emission (ASE) and lasing from colloidal QDs of Znprocessed AgIn5S8 (AIS) for the first time. The passivation treatment on the AIS QDs yields a 3.4-fold enhancement of fluorescence quantum efficiency and a 30% increase in the twophoton absorption cross section. ASE is achieved from the AIS/ ZnS core/shell QD films under both one- and two-photon pumping with a threshold fluence of -,84.5 mu J/cm2 and 3.1 mJ/cm2, respectively. These thresholds are comparable to the best optical gain performance of Cd based-QDs reported in the literature. Moreover, we demonstrate a facile whispering-gallery-mode microlaser of the core/shell QDs with a lasing threshold of -,233 mu J/cm2. The passivated AIS QDs can be promising optical gain media for photonic applications.

Automated summary

I-III-VI ternary quantum dots (QDs) have been proposed as non-toxic alternatives to II-VI QDs in optoelectronics and biotechnology. However, their application as optical gain media for microlasers is constrained by low neous emission (ASE) and lasing. In this study, passivated AIS QDs showed enhanced fluorescence efficiency and two-photon absorption cross section. ASE was achieved from AIS/ZnS core/shell QD films under both one- and two-photon pumping, with comparable thresholds to Cd-based QDs. A whispering-gallery-mode microlaser of the core/shell QDs was also demonstrated.