Distinctive Field-Effect Transistors and Ternary Inverters Using Cross-Type WSe2/MoS2Heterojunctions Treated with Polymer Acid

Jun Young Kim, Hyeon Jung Park, Sang Hun Lee, Changwon Seo, Jeongyong Kim, Jinsoo Joo

Research output: Contribution to journalArticlepeer-review

Abstract

The electrical and optical characteristics of two-dimensional (2D) transition-metal dichalcogenides (TMDCs) can be improved by surface modification. In this study, distinctive field-effect transistors (FETs) were realized by forming cross-type 2D WSe2/MoS2 p-n heterojunctions through surface treatment using poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-PMAA). The FETs were applied to new ternary inverters as multivalued logic circuits (MVLCs). Laser confocal microscope photoluminescence spectroscopy indicated the generation of trions in the WSe2 and MoS2 layers, and the intensity decreased after PMMA-co-PMAA treatment. For the cross-type WSe2/MoS2 p-n heterojunction FETs subjected to PMMA-co-PMAA treatment, the channel current and the region of anti-ambipolar transistor characteristics increased considerably, and ternary inverter characteristics with three stable logic states, "1", "1/2", and "0", were realized. Interestingly, the intermediate logic state 1/2, which results from the negative differential transconductance characteristics, was realized by the turn-on of all component FETs, as the current of the FETs increased after PMMA-co-PMAA treatment. The electron-rich carboxyl acid moieties in PMMA-co-PMAA can undergo coordination with the metal Mo or W atoms present in the Se or S vacancies, respectively, resulting in the modulation of charge density. These features yielded distinctive FETs and ternary inverters for MVLCs using cross-type WSe2/MoS2 heterojunctions.

Original languageEnglish
Pages (from-to)36530-36539
Number of pages10
JournalACS Applied Materials and Interfaces
Volume12
Issue number32
DOIs
Publication statusPublished - 2020 Aug 12

Keywords

  • field-effect transistor
  • heterojunction
  • surface treatment
  • ternary inverter
  • transition-metal dichalcogenide

ASJC Scopus subject areas

  • Materials Science(all)

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