Nanocavity Integrated van der Waals Heterostructure Light-Emitting Tunneling Diode

Abstract

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 WSe 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.

Midinfrared Electro-optic Modulation in Few-Layer Black Phosphorus

“…Those include photodetectors [4][5][6][7][8][9][10][11][12] , optical modulators [13][14][15] , light emitters and laser diodes [16][17][18] . The diverse optical and electronic properties of 2D materials enable optoelectronic functions covering a broad spectral range from the ultraviolet to the visible, and from the infrared (IR) to the terahertz.…”

Light Sources and Photodetectors Enabled by 2D Semiconductors

“…Furthermore, with the vertically stacked heterostructures made of multilayer MoS 2 or WSe 2 , Al 2 O 3 , and GaN, unconventionally electric‐induced EL associated with the direct excitonic transition has been observed from multilayer MoS 2 or WSe 2 , which paves the way to the development of atomically thin LEDs based on multilayer indirect‐bandgap semiconductors. By integrating a 1L WSe 2 LED with a photonic‐crystal cavity, enhanced EL was realized and high‐speed modulation was achieved . In addition, with the help of an electrolyte film, centimeter‐scale LEDs based on 1L WSe 2 and MoS 2 have been accomplished, which takes an important step toward the realization of large‐area lighting applications based on 2D semiconductors .…”

“…In the aspect of light sources, one remaining challenge is regarding the finite emission colors of present 2DLEDs, which limits their further practical applications for displays and illumination. Up to now, the main emission of the reported 2DLEDs has covered the orange, red, and near‐infrared spectral ranges, while 2DLEDs dominantly emitting from the ultraviolet to yellow wavelengths are still lacking. In particular, blue and green 2DLEDs are highly desired to realize 2D semiconductor–based full‐color displays and while‐light illumination.…”

Recent Advances in van der Waals Heterojunctions Based on Semiconducting Transition Metal Dichalcogenides

“…Yang and co-workers [87] LEDs Gr/h-BN/WSe 2 /h-BN/Gr MX 2 /insulator Modulation speed ≈ 1 MHz Liu et al [142] h-BN/Gr/2h-BN/ WS 2 /2h-BN/Gr/h-BN…”

“…LEDs rely on a junction with a built-in electric field, which promotes the recombination of electrons and holes. [142] The EL of the LED can be significantly enhanced, and its modulation speed is increased to ≈1 MHz when voltage pulses are applied. For 2D materials, it is difficult to form p-n junction through the doping method because of the ultrathin thickness.…”