Transfer-free, scalable vertical heterostructure FET on MoS2/WS2 continuous films


NANOTECHNOLOGY, vol.33, no.47, 2022 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 33 Issue: 47
  • Publication Date: 2022
  • Doi Number: 10.1088/1361-6528/ac8997
  • Journal Name: NANOTECHNOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Biotechnology Research Abstracts, Communication Abstracts, Compendex, EMBASE, INSPEC, MEDLINE, Metadex, Civil Engineering Abstracts
  • Keywords: TMDC, WS2, MoS2, 2D heterostructures, ambipolar FET, sputtering, FIELD-EFFECT TRANSISTORS, LARGE-AREA, GRAPHENE, WS2, TRANSPORT, BEHAVIOR, STEP
  • Eskisehir Osmangazi University Affiliated: Yes


Taking into account the novel layered structure and unusual electronic properties of MoS2 and WS2 on the side the lack of dangling bonds between these two components and donor-acceptor linkage effects, growth of the MoS2/WS2 vertical heterojunction film on the amorphous SiO2/Si substrate have created high demand. In this study, we reported the continuous, scalable, and vertical MoS2/WS2 heterostructure film by using a sputtering without a transfer step. The WS2 film was continuously grown on MoS2 and eventually led to the formation of the MoS2/WS2 vertical heterojunction film. Dozens of FETs fabricated on MoS2/WS2 continuous heterojunction film were created on the same substrate in a single lithographic fabrication step, allowing them to be commercialized and not only used in research applications. RAMAN spectra proved the formation of the MoS2/WS2 heterostructure film. In XPS measurements, it was shown that a separate MoS2 and WS2 layer was grown instead of the alloy structure. The polarity behavior of the MoS2/WS2 heterostructure FET was found to be modulated with different drain voltages as p-type to ambipolar and finally n-type conductivity because of the transition of band structure and Schottky barrier heights at different drain voltages. Electron mobility (7.2 cm(2) V.s(-1)) and on/off ratio (10(4)-10(5)) exhibited by the MoS2/WS2 heterostructure FETs displayed a more improved electrical performance than that of individual WS2, MoS2 devices. It was observed that the mobility value of MoS2/WS2 FET was approximately 514 times greater than WS2 FET and 800 times greater than MoS2 FET. Additionally, the MoS2/WS2 FET on/off ratio was larger than 2 order MoS2 FET and 1 order WS2 FET. The film of continuous vertical heterojunctions as in the MoS2/WS2 currents in the study would be a promising candidate for nanoelectronics fields. This work demonstrated the progress towards realizing carrier-type controlled high-performance MoS2/WS2 heterojunction-based FETs for future logic devices.