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

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 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.