posted on 2016-12-07, 00:00authored byChang-Hua Liu, Genevieve Clark, Taylor Fryett, Sanfeng Wu, Jiajiu Zheng, Fariba Hatami, Xiaodong Xu, Arka Majumdar
Developing
a nanoscale, integrable, and electrically pumped single mode light
source is an essential step toward on-chip optical information technologies
and sensors. Here, we demonstrate nanocavity enhanced electroluminescence
in van der Waals heterostructures (vdWhs) at room temperature. The
vertically assembled light-emitting device uses graphene/boron nitride
as top and bottom tunneling contacts and monolayer WSe2 as an active light emitter. By integrating a photonic crystal cavity
on top of the vdWh, we observe the electroluminescence is locally
enhanced (>4 times) by the nanocavity. The emission at the cavity
resonance is single mode and highly linearly polarized (84%) along
the cavity mode. By applying voltage pulses, we demonstrate direct
modulation of this single mode electroluminescence at a speed of ∼1
MHz, which is faster than most of the planar optoelectronics based
on transition metal chalcogenides (TMDCs). Our work shows that cavity
integrated vdWhs present a promising nanoscale optoelectronic platform.