Print Email Facebook Twitter Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots Title Continuous-wave infrared optical gain and amplified spontaneous emission at ultralow threshold by colloidal HgTe quantum dots Author Geiregat, P.A. (Universiteit Gent) Houtepen, A.J. (TU Delft ChemE/Opto-electronic Materials; Universiteit Gent) Sagar, Laxmi Kishore (Universiteit Gent) Infante, Ivan (Vrije Universiteit Amsterdam) Zapata, Felipe (Vrije Universiteit Amsterdam) Grigel, Valeriia (Universiteit Gent) Allan, Guy (IEMN Institut d'Electronique de Microelectronique et de Nanotechnologie) Delerue, Christophe (IEMN Institut d'Electronique de Microelectronique et de Nanotechnologie) Van Thourhout, Dries (Universiteit Gent) Hens, Zeger (Universiteit Gent) Date 2018-01-01 Abstract Colloidal quantum dots (QDs) raise more and more interest as solution-processable and tunable optical gain materials. However, especially for infrared active QDs, optical gain remains inefficient. Since stimulated emission involves multifold degenerate band-edge states, population inversion can be attained only at high pump power and must compete with efficient multi-exciton recombination. Here, we show that mercury telluride (HgTe) QDs exhibit size-tunable stimulated emission throughout the near-infrared telecom window at thresholds unmatched by any QD studied before. We attribute this unique behaviour to surface-localized states in the bandgap that turn HgTe QDs into 4-level systems. The resulting long-lived population inversion induces amplified spontaneous emission under continuous-wave optical pumping at power levels compatible with solar irradiation and direct current electrical pumping. These results introduce an alternative approach for low-threshold QD-based gain media based on intentional trap states that paves the way for solution-processed infrared QD lasers and amplifiers. To reference this document use: http://resolver.tudelft.nl/uuid:d146c30f-04c8-4e02-a666-9e06da90a6df DOI https://doi.org/10.1038/NMAT5000 Embargo date 2018-04-09 ISSN 1476-1122 Source Nature Materials, 17 (1), 35-42 Bibliographical note Accepted Author Manuscript Part of collection Institutional Repository Document type journal article Rights © 2018 P.A. Geiregat, A.J. Houtepen, Laxmi Kishore Sagar, Ivan Infante, Felipe Zapata, Valeriia Grigel, Guy Allan, Christophe Delerue, Dries Van Thourhout, Zeger Hens Files PDF Accepted_Manuscript.pdf 1010.84 KB Close viewer /islandora/object/uuid:d146c30f-04c8-4e02-a666-9e06da90a6df/datastream/OBJ/view