Waveguide‐Coupled Colloidal Quantum Dot Light Emitting Diodes and Detectors on a Silicon Nitride Platform
Lukas Elsinger, Robin Petit, Frederik Van Acker, Natalia K. Zawacka, Ivo Tanghe, Kristiaan Neyts, Christophe Detavernier, Pieter Geiregat, Zeger Hens, Dries Van Thourhout
Abstract
Abstract Colloidal quantum dots (QDs) are an attractive light source for visible photonics, in particular their widely tunable emission wavelength, inexpensive wet‐chemical synthesis and straight‐forward hybrid integration can make the difference. In this work, integrated light‐emitting diodes are demonstrated based on CdSe/CdS QDs, with the emission directly coupled to a silicon nitride waveguide. The devices feature a record current density of up to 100 A cm −2 and a maximum on‐chip power density of almost 1.5 W cm −2 in a single‐mode waveguide. Operated as detectors, the photodiodes have a low dark current of 1.5 µA cm −2 . It is anticipated, that the devices will find an application in chip‐based absorption spectroscopy and bio‐sensing, as they can be post‐processed on foundry‐fabricated waveguide platforms, at a low cost. In addition, this approach provides the missing low‐loss waveguide layer, necessary for building an electrically pumped laser using colloidal QDs.