Asymmetrically strained quantum dots with non-fluctuating single-dot emission spectra and subthermal room-temperature linewidths

• Published in: Nature materials 2019-03, Vol.18 (3), p.249-255
• Main Authors: Park, Young-Shin, Lim, Jaehoon, Klimov, Victor I.
• Format: Article
• Language: English
• Subjects: 140/125; 639/624/400/3925; 639/925/357/1017; Asymmetry; Biomaterials; Blinking; Chemistry and Materials Science; Compressive strength; Condensed Matter Physics; Electrons; Emission spectra; Emissions; Fluctuations; Heterostructures; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Light sources; Material Science; Materials Science; Nanotechnology; Optical and Electronic Materials; Quantum dots; Room temperature; Variation; Wurtzite
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-018-0254-7

The application of colloidal semiconductor quantum dots as single-dot light sources still requires several challenges to be overcome. Recently, there has been considerable progress in suppressing intensity fluctuations (blinking) by encapsulating an emitting core in a thick protective shell. However, these nanostructures still show considerable fluctuations in both emission energy and linewidth. Here we demonstrate type-I core/shell heterostructures that overcome these deficiencies. They are made by combining wurtzite semiconductors with a large, directionally anisotropic lattice mismatch, which results in strong asymmetric compression of the emitting core. This modifies the structure of band-edge excitonic states and leads to accelerated radiative decay, reduced exciton–phonon interactions, and suppressed coupling to the fluctuating electrostatic environment. As a result, individual asymmetrically strained dots exhibit highly stable emission energy (