| AVS 66th International Symposium & Exhibition | |
| 2D Materials | Tuesday Sessions |
| Session 2D+AS+MI+NS-TuM |
| Session: | 2D Materials Characterization including Microscopy and Spectroscopy |
| Presenter: | Daniel Lizzit, Elettra - Sincrotrone Trieste, Trieste, Italy |
| Authors: | L. Bignardi, University of Trieste, Italy D. Lizzit, Elettra - Sincrotrone Trieste, Trieste, Italy B. Harsh, Department of Physics, University of Trieste, Italy E. Travaglia, Department of Physics, University of Trieste, Italy C.E. Sanders, iNANO, Aarhus University, Denmark, UK M. Dendzik, Aarhus University, Denmark, Germany P. Lacovig, Elettra-Sincrotrone Trieste, Italy M. Michiardi, iNANO, Aarhus University, Denmark, Canada M. Bianchi, Aarhus University, Denmark R. Larciprete, CNR-Institute for Complex Systems, Roma, Italy J.I. Flege, University of Bremen, Germany J. Falta, University of Bremen, Germany P.K. Das, Abdus Salam International Centre for Theoretical Physics, Trieste, Italy J. Fujii, IOM-CNR, Laboratorio TASC, Trieste, Italy I. Vobornik, IOM-CNR, Laboratorio TASC, Trieste, Italy M. Ewert, University of Bremen, Germany L. Buß, University of Bremen, Germany A. Baraldi, University of Trieste, Italy P. Hofmann, Aarhus University, Denmark S. Lizzit, Elettra - Sincrotrone Trieste, Trieste, Italy |
| Correspondent: | Click to Email |
It has been widely demonstrated that Transition Metal Dichalcogenides (TMDs), and in particular MoS2 and WS2 could be good candidates for future electronic devices because of their intrinsic electronic properties and their potential for ultimate device scaling. In the single layer (SL) form, the inversion symmetry breaking and the strong spin-orbit coupling of the heavy transition metals (Mo or W) open new possibilities for data storage and computing thanks to the spin and valley degrees of freedom. However, in order to investigate the fundamental physics behind these materials and to produce high quality electronic devices, SL TMDs with enough large area and high quality are demanded. In particular, single domain oriented layers, that are SLs without mirror domains, allow to strongly suppress defects due to the absence of grain boundaries which are known to degrade the overall performances.
We here present a successful synthesis method based on physical vapor deposition that consists in dosing W or Mo in H2S atmosphere onto Au(111), and provide an in-depth characterization of the synthesized SL TMDs through different surface science techniques. Synchrotron radiation based photoelectron spectroscopy in the fast modality (fast-XPS) was used to carefully tune the growth parameters whereas high resolution (HR-XPS) was used for the characterization. In particular fast-XPS allowed to optimize the growth parameters which turned out to be different for MoS2 [1] with respect to WS2[2]. Then, photoelectron diffraction (XPD) was employed to find the structural parameters of the SLs and to unambiguously determine their single orientation character and the relative alignment with respect to the underlying substrate. Scanning Tunneling Microscopy (STM), Low Energy Electron Diffraction (LEED) and Microscopy (LEEM) added further insight into the lateral extension of the SLs and the structural order at the atomic level.
[1] H. Bana, E. Travaglia, L. Bignardi, P. Lacovig, C. E. Sanders, M. Dendzik, M. Michiardi, M. Bianchi, D. Lizzit, F. Presel, D. D. Angelis, N. Apostol, P. K. Das, J. Fujii, I. Vobornik, R. Larciprete, A. Baraldi, P. Hofmann and S. Lizzit, 2D Materials, 2018, 5, 035012.
[2] L. Bignardi, D. Lizzit, H. Bana, E. Travaglia, P. Lacovig, C. E. Sanders, M. Dendzik, M. Michiardi, M. Bianchi, M. Ewert, L. Buss, J. Falta, J. I. Flege, A. Baraldi, R. Larciprete, P. Hofmann, and S. Lizzit, Physical Review Materials 3, 014003 (2019).