A new method that enables a dual-channel field-effect-transistor (FET) based on a vertically stacked heterostructure of ultrathin n-type MoS2 and p-type WSe2 layers for the study of parallel carrier transport was demonstrated. First, a MoS2 layer was mechanically exfoliated on a SiO2/Si substrate by the Scotch tape method. The electrodes were patterned by photolithography, followed by e-beam evaporation of Ti/Pt (15/10 nm). An exfoliated WSe2 layer was transferred onto the device region by the poly(methyl methacrylate) (PMMA)-transfer method, resulting in the formation of a WSe2/MoS2 heterostructure and the contact of WSe2 with the Pt electrode. To investigate the optical properties of the WSe2/MoS2 heterostructure, Raman spectroscopy was employed using a laser with a wavelength of 532 nm. To study the optoelectronic interactions in the heterostructure, photoluminescence (PL) measurements were performed using a laser with a wavelength of 514 nm. Before measurement of the dual-channel WSe2/MoS2 FETs, the single-channel FETs of MoS2 and WSe2 were separately measured to confirm the doping polarity in each channel material. The transfer characteristics of the single-channel MoS2 (WSe2) FET with Ti (Pt) electrodes showed n-type (p-type) unipolar transport. The vertically stacked p- and n-channel heterostructure reduces device fabrication complexities, specifically for ambipolar CMOS invertors. The dual-channel FET demonstrates novel optoelectrical applications of TMDs in stacked 2D materials to achieve highly dense electronics.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Nos. 2013R1A2A2A01069023 and 2015H1D3A1062519). This work was partly supported by Institute for Information and Communications Technology Promotion (IITP) grant funded by the Korea government (MSIP) (B0117-16-1003, Fundamental technologies of 2D materials and devices for the platform of new-functional smart devices).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering