Looking Inside a Working SiLED

In this study, we investigate for the first time morphological and compositional changes of silicon quantum dot (SiQD) light-emitting diodes (SiLEDs) upon device operation. By means of advanced transmission electron microscopy (TEM) analysis including energy filtered TEM (EFTEM) and energy dispersiv...

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Bibliographic Details
Published in:Nano letters 2013-08, Vol.13 (8), p.3539-3545
Main Authors: Maier-Flaig, Florian, Kübel, Christian, Rinck, Julia, Bocksrocker, Tobias, Scherer, Torsten, Prang, Robby, Powell, Annie K, Ozin, Geoffrey A, Lemmer, U
Format: Article
Language:English
Subjects:
Applied sciences
Cross-disciplinary physics: materials science
rheology
Degradation
Devices
Electric potential
Electroluminescence
Electronics
Exact sciences and technology
Failure analysis
Materials science
Molecular electronics, nanoelectronics
Nanocrystalline materials
Nanoscale materials and structures: fabrication and characterization
Optoelectronic devices
Physics
Quantum dots
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Transmission electron microscopy
Voltage
X-rays
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Summary:In this study, we investigate for the first time morphological and compositional changes of silicon quantum dot (SiQD) light-emitting diodes (SiLEDs) upon device operation. By means of advanced transmission electron microscopy (TEM) analysis including energy filtered TEM (EFTEM) and energy dispersive X-ray (EDX) spectroscopy, we observe drastic morphological changes and degradation for SiLEDs operated under high applied voltage ultimately leading to device failure. However, SiLEDs built from size-separated SiQDs operating under normal conditions show no morphological and compositional changes and the biexponential loss in electroluminescence seems to be correlated to chemical and physical degradation of the SiQDs. By contrast, we found that, for SiLEDs fabricated from polydisperse SiQDs, device degradation is more pronounced with three main modes of failure contributing to the reduced overall lifetime compared to those prepared from size-separated SiQDs. With this newfound knowledge, it is possible to devise ways to increase the lifetimes of SiLEDs.
ISSN:1530-6984
1530-6992
DOI:10.1021/nl400975u