Sub-single-exciton lasing using charged quantum dots coupled to a distributed feedback cavity

• Published in: Science (American Association for the Advancement of Science) Vol. 365; no. 6454; pp. 672 - 675
• Main Authors: Kozlov, Oleg V, Park, Young-Shin, Roh, Jeongkyun, Fedin, Igor, Nakotte, Tom, Klimov, Victor I
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 16.08.2019; American Association for the Advancement of Science (AAAS)
• Subjects: Augers; Carrier recombination; Charging; Complications; Electrons; Epitaxial growth; Excitons; Lasers; Lasing; Material Science; MATERIALS SCIENCE; Optical properties; Quantum dots; Recombination; Semiconductor materials
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aax3489

Colloidal semiconductor quantum dots (QDs) are attractive materials for realizing highly flexible, solution-processable optical gain media, but they are difficult to use in lasing because of complications associated with extremely short optical-gain lifetimes limited by nonradiative Auger recombination. By combining compositional grading of the QD's interior for hindering Auger decay with postsynthetic charging for suppressing parasitic ground-state absorption, we can reduce the lasing threshold to values below the single-exciton-per-dot limit. As a favorable departure from traditional multi-exciton-based lasing schemes, our approach should facilitate the development of solution-processable lasing devices and thereby help to extend the reach of lasing technologies into areas not accessible with traditional, epitaxially grown semiconductor materials.