A new all-2-D light-emitting field-effect transistor

2D Sheets

Transition metal dichalcogenides (TMDs), a two-dimensional (2-D) semiconductor, are promising materials for next-generation optoelectronic devices. They can emit strong light due to the large binding energies of excitons, quasiparticles composed of electron-hole pair, as well as an atomically thin nature. In existing 2-D light emitting devices, however, the simultaneous injection of electrons and holes into 2-D materials has been challenging, which results in low light emission efficiency.

To overcome these problems, Prof. Gwan-Hyoung Lee's group in Seoul National University and Prof. Chul-Ho Lee's group in Korea University demonstrated all-2-D light-emitting field-effect transistors (LEFETs) by staking 2-D materials. They chose graphene and monolayer WSe2 as contact electrode and an ambipolar channel, respectively. Typically, a junction between metal and semiconductor has a large energy barrier. It is the same at a junction of graphene and WSe2.

However, Lee's group utilized the barrier-tunable graphene electrode as a key for the selective injection of electrons and holes. Since the work function of graphene can be tuned by an external electric field, the contact barrier height can be modulated in the graphene-contacted WSe2 transistor, enabling selective injection of electrons and holes at each graphene contact. By controlling the densities of injected electrons and holes, high efficiency of electroluminescence as high as 6% was achieved at room temperature.

In addition, it was demonstrated that, by modulating the contacts and channel with separate three gates, the polarity and light emission of LEFETs can be controlled, showing great promises of the all-2-D LEFETs in multi-digit logic devices and highly integrated optoelectronic circuitry.

This research is published as a paper entitled "Multi-operation mode light-emitting field-effect transistors based on van der Waals heterostructure" in Advanced Materials.


Multioperation‐Mode Light‐Emitting Field‐Effect Transistors Based on van der Waals Heterostructure

Junyoung Kwon, June‐Chul Shin, Huije Ryu, Jae Yoon Lee, Dongjea Seo, Kenji Watanabe, Takashi Taniguchi, Young Duck Kim, James Hone, Chul‐Ho Lee, Gwan‐Hyoung Lee

DOI: 10.1002/adma.202003567


Gwan-Hyoung Lee

Associate Professor

Materials Science and Engineering

Seoul National University


Seoul National University

Spin defects under control

UMass Amherst team discovers use of elasticity to position microplates on curved 2D fluids

The spintronics technology revolution could be just a hopfion away

Scientists watch 2D puddles of electrons emerge in a 3D superconducting material

Lighting the way to folding next-level origami

Energy transmission by gold nanoparticles coupled to DNA structures

A breakthrough that enables practical semiconductor spintronics

SMART discovers the science behind varying performance of different colored LEDs

Optically active defects improve carbon nanotubes

Discovery could help lengthen lifespan of electronic devices