MXene Electrode for the Integration of WSe2 and MoS2 Field Effect Transistors

• Published in: Advanced functional materials Vol. 26; no. 29; pp. 5328 - 5334
• Main Authors: Xu, Jiao, Shim, Jaewoo, Park, Jin-Hong, Lee, Sungjoo
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 02-08-2016
• Subjects: 2D field effect transistor; barrier height; layered electrode material; transition metal carbides
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201600771

Recently, MXenes, which are 2D early transition metal carbides and carbonitrides, have attracted wide attention because of their excellent conductivities. Here, the electrode applications of Ti2C(OH)xFy, one member of the MXene family, in WSe2 and MoS2 field effect transistors (FETs) are assessed. Kelvin probe force microscopy analysis is performed to determine its work function, which is estimated to be ≈4.98 eV. Devices based on WSe2/Ti2C(OH)xFy and MoS2/Ti2C(OH)xFy heterostructures are fabricated with the mechanical transfer method and their electronic performances evaluated. The temperature‐dependent current–voltage transfer characteristics of the devices are determined to extract their Schottky barrier heights. The hole barrier between WSe2 and Ti2C(OH)xFy is estimated to be ≈0.23 eV and the electron barrier between the MoS2 band and Ti2C(OH)xFy is ≈0.19 eV, which indicates that the pinning effect occurs at the MoS2/Ti2C(OH)xFy interface but not at the WSe2/Ti2C(OH)xFy interface; this difference arises because of the difference between the band structures of WSe2 and MoS2. A complementary metal–oxide–semiconductor inverter based on these electrode properties of Ti2C(OH)xFy with MoS2 (n‐channel) and WSe2 (p‐channel) is fabricated, which demonstrates that Ti2C(OH)xFy is a promising electrode for future nanoelectronics applications.
By using Ti2C(OH)xFy as an electrode for the integration of 2D p‐FET (WSe2) and n‐FET (MoS2), the heights of the hole barriers of WSe2/Ti2C(OH)xFy and MoS2/Ti2C(OH)xFy are determined to be 0.23 eV and 0.19 eV, respectively. A complementary metal–oxide–semiconductor inverter is fabricated, which demonstrates that Ti2C(OH)xFy is a promising electrode for future nanoelectronics applications.