High-performance multilayer WSe2 field-effect transistors with carrier type control

摘要

In this study,high-performance multilayer WSe2 field-effect transistor (FET) devices with carrier type control are demonstrated via thickness modulation and a remote oxygen plasma surface treatment.Carrier type control in multilayer WSe2 FET devices with Cr/Au contacts is initially demonstrated by modulating the WSe2 thickness.The carrier type evolves with increasing WSe2 channel thickness,being p-type,ambipolar,and n-type at thicknesses ＜ 3,～ 4,and ＞ 5 nm,respectively.The thickness-dependent carrier type is attributed to changes in the bandgap of WSe2 as a function of the thickness and the carrier band offsets relative to the metal contacts.Furthermore,we present a strong hole carrier doping effect via remote oxygen plasma treatment.It non-degenerately converts n-type characteristics into p-type and enhances field-effect hole mobility by three orders of magnitude.This work demonstrates progress towards the realization of high-performance multilayer WSe2 FETs with carrier type control,potentially extendable to other transition metal dichalcogenides,for future electronic and optoelectronic applications.