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Open AccessArticle

Silicon Quantum Dot Light Emitting Diode at 620 nm

by Hiroyuki Yamada 1,2 and Naoto Shirahata 1,2,3,*
International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
Department of Physics, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan
Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
Author to whom correspondence should be addressed.
Micromachines 2019, 10(5), 318;
Received: 29 April 2019 / Revised: 8 May 2019 / Accepted: 10 May 2019 / Published: 11 May 2019
(This article belongs to the Special Issue Silicon Photonics Bloom)
Here we report a quantum dot light emitting diode (QLED), in which a layer of colloidal silicon quantum dots (SiQDs) works as the optically active component, exhibiting a strong electroluminescence (EL) spectrum peaking at 620 nm. We could not see any fluctuation of the EL spectral peak, even in air, when the operation voltage varied in the range from 4 to 5 V because of the possible advantage of the inverted device structure. The pale-orange EL spectrum was as narrow as 95 nm. Interestingly, the EL spectrum was narrower than the corresponding photoluminescence (PL) spectrum. The EL emission was strong enough to be seen by the naked eye. The currently obtained brightness (∼4200 cd/m2), the 0.033% external quantum efficiency (EQE), and a turn-on voltage as low as 2.8 V show a sufficiently high performance when compared to other orange-light-emitting Si-QLEDs in the literature. We also observed a parasitic emission from the neighboring compositional layer (i.e., the zinc oxide layer), and its intensity increased with the driving voltage of the device. View Full-Text
Keywords: quantum dot; silicon nanocrystals; light emitting diode quantum dot; silicon nanocrystals; light emitting diode
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Yamada, H.; Shirahata, N. Silicon Quantum Dot Light Emitting Diode at 620 nm. Micromachines 2019, 10, 318.

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