Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.
DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.
An experimental method is demonstrated for the determination of internal quantum efficiency (IQE) in III-nitride-based light-emitting diodes (LEDs). LED devices surrounded with an optically absorbing material have been fabricated to limit collected light t ...
Thin-film InGaN photonic crystal (PhC) light-emitting diodes (LEDs) with a total semiconductor thickness of either 800 nm or 3.45 mu m were fabricated and characterized. Increased directional radiance relative to Lambertian emission was observed for both c ...
The light extraction efficiency of photonic-crystal (PhC) light-emitting diodes (LEDs) relies on the competition between the PhC extraction and dissipation mechanisms of the guided light within the LED. This work presents the experimental determination of ...
A quantum dot is a semiconductor nanostructure that confines the motion of conduction band electrons and valence band holes in all three spatial directions, thus creating fully discrete energy levels. The confinement in the InAs/GaAs material system is gen ...
Gallium Nitride (GaN) and its ternary alloys with aluminium and indium have met a growing interest in the last decade. These semiconductors have a large direct bandgap and can be doped with either silicon (Si) for n-type and magnesium (Mg) for p-type layer ...
A novel, highly blue luminescent molecule containing donor and acceptor groups, 4,4 prime -di-(2-(2,5-dimethoxyphenyl)ethenyl)-2,2 prime -bipyridine, that shows photoluminescence emission at 450 nm with 43% quantum yield is designed and synthesized. Time d ...
The present doctoral thesis aims to contribute to the field of organic semiconductor physics and technology, both of which have become fast growing disciplines. Two technological applications are emerging from these research efforts: Organic light-emitting ...
Self-assembled quantum-dots (QDs) represent a distributed ensemble of zero dimensional structures with a near-singular density of states. Implemented as the active medium in a diode laser their unique properties lead to improved and often novel characteris ...
It was about 125 years ago that the light bulb was commercialized by Thomas Edison. No doubt a brilliant invention at the time, today its low power conversion efficiency is one of the reasons why lighting in the western world has such high energy consumpti ...
We present a theoretical and experimental study of a multilayer organic light emitting device (OLED) with a partially doped emission layer. An extended version of our established "MOLED" device model is used to understand the effects of the partially doped ...
