Multioperation‐Mode Light‐Emitting Field‐Effect Transistors Based on van der Waals Heterostructure. Issue 43 (11th September 2020) - Kwon, Junyoung
Abstract: 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. Abstract : A light‐emitting transistor based on a van der Waals heterostructure is demonstrated. Utilizing tunable graphene contacts, holes and electrons are separately injected into the ambipolar WSe2 monolayer. By balanced recombination of electrons and holes, the external quantum efficiency reaches ≈6% at room temperature. Multimode operation of this device powered by combination of electrical and optical states would be beneficial for optical circuitry.