2D semiconductors have shown great potential for application to electrically tunable optoelectronics. Despite the strong excitonic photoluminescence (PL) of monolayer transition metal dichalcogenides (TMDs), their efficient electroluminescence (EL) has not been achieved due to the low efficiency of charge injection and electron–hole recombination. Here, multioperation-mode light-emitting field-effect transistors (LEFETs) consisting of a monolayer WSe2 channel and graphene contacts coupled with two top gates for selective and balanced injection of charge carriers are demonstrated. Visibly observable EL is achieved with the high external quantum efficiency of ≈6% at room temperature due to efficient recombination of injected electrons and holes in a confined 2D channel. Further, electrical tunability of both the channel and contacts enables multioperation modes, such as antiambipolar, depletion,and unipolar regions, which can be utilized for polarity-tunable field-effect transistors and photodetectors. The work exhibits great potential for use in 2D semiconductor LEFETs for novel optoelectronics capable of high efficiency, multifunctions, and heterointegration.
Bibliographical noteFunding Information:
This work was supported by Samsung Research Funding Center of Samsung Electronics under Project Number SRFC-MA1502-12, the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning by the Korean government (2018M3D1A1058793, 2019R1F1A1058420, 2020R1A2C2009389 and 2017R1A5A1014862, SRC program: vdWMRC center). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, Grant Number JPMXP0112101001, JSPS KAKENHI Grant Numbers JP20H00354 and the CREST(JPMJCR15F3), JST. C.-H.L. acknowledges the support from the KU-KIST School Project. Synthesis of WSe2 at Columbia was supported by the NSF MRSEC program through the Center for Precision Assembly of Superstratic and Superatomic Solids (DMR-1420634).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering