Waveguide-Coupled Colloidal Quantum Dot Light Emitting Diodes and Detectors on a Silicon Nitride Platform

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 mu A 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.

Automated summary

Colloidal quantum dots (QDs) are shown to be a promising light source for visible photonics, with integrated LED devices featuring high current density, power density, and low dark current. These devices are expected to find applications in absorption spectroscopy, bio-sensing, and could potentially be used for building electrically pumped lasers at a low cost.