High‐Speed Electroluminescence Modulation in Monolayer WS₂

Abstract

The high‐speed modulation of the nanoscale light sources is of fundamental interest in nanophotonics. Here, electrically driven light emission from a metal–insulator–semiconductor heterostructure consisting of graphene, hexagonal boron nitride (h‐BN), and monolayer tungsten disulfide (WS2) is demonstrated. Electroluminescence in these devices originates from radiative recombination of majority carriers (electrons) accumulated by electrostatic doping and hot minority carriers (holes) injected into monolayer WS2 from graphene through an ultrathin h‐BN tunnel barrier. The devices are electrically driven with a radio frequency signal and electrical modulation of the light emission at frequencies up to 1.5 GHz is demonstrated. The high‐speed WS2 tunnel diodes provide a promising path for on‐chip nanophotonics.

AC-driven multicolor electroluminescence from a hybrid WSe2 monolayer/AlGaInP quantum well light-emitting device

“…6–9 Many works have indicated the potential of TMDCs for light-emitting modulators due to their short exciton lifetime. 10–16…”

“…[6][7][8][9] Many works have indicated the potential of TMDCs for light-emitting modulators due to their short exciton lifetime. [10][11][12][13][14][15][16] TMDC-based light-emitting devices with various structures have been demonstrated by several groups. [17][18][19][20][21] The structures of electroluminescent (EL) devices based on 2D TMDC materials can be mainly divided into two types in accordance with the driving source: (i) p-n junction structures and (ii) capacitor structures.…”

Monolayer WS2 electro- and photo-luminescence enhancement by TFSI treatment

“…Layered material heterostructures (LMHs) combining single layer graphene (SLG), 1L-TMDs, and hexagonal boron nitride (hBN), from 1L-hBN to hundreds of layers, are promising for electronics [13,14], photonics [15], and optoelectronics [16,17]. Direct bandgap 1L-TMDs and LMHs can be used to make light-emitting diodes (LEDs) [18][19][20][21][22][23][24][25][26][27], with fast modulation speed (up to GHz) [7,25,28], and emission wavelength tunability [6,7,25] besides multi-spectral (visible ∼618 nm [21][22][23] to near-infrared ∼1160 nm [29,30]) emission.…”

“…ratio between emitted photons and injected electrons (e) [19,20], depends on the optical emission of the material [30][31][32][33][34][35][36][37], as well as on its doping level [6,[38][39][40][41]. In doped 1L-TMDs, the PL and EL emission originates from either negative (X − ) [28,33,34,38] or positive (X + ) [6,19,20] trions, depending on the type of doping. However, 1L-TMD-LEDs based on trionic emission show low η EL (typically <0.05% [19,20]) with respect to neutral exciton (X 0 ) emission (typically η EL <1% [6,7,31,32,38,39]).…”

Electroluminescence from Megasonically Solution-Processed MoS2 Nanosheet Films

“…An outstanding challenge in 2D material optoelectronics is the scalable solution-based fabrication of large-area electroluminescent devices. For example, the majority of studies on electroluminescent TMDs have utilized mechanically exfoliated nanosheets ,,− ,,,,,− that cannot be mass-produced. While wafer-scale electroluminescent TMD monolayers can be synthesized by chemical vapor deposition (CVD), , these CVD-grown TMD materials suffer from two principal limitations.…”