Suchergebnisse

Thin layer MoS2-based field effect transistors (FET) are emerging candidates to fabricate very fast and sensitive devices. Here, we demonstrate a method to fabricate very narrow transistor channel widths on a single layer MoS2 flake connected to gold electrodes. Oxidation scanning probe lithography is applied to pattern insulating barriers on the flake. The process narrows the electron path to about 200 nm. The output and transfer characteristics of the fabricated FET show a behavior that is consistent with the minimum channel width of the device. The method relies on the direct and local chemical modification of MoS2. The straightforward character and the lack of specific requirements envisage the controlled patterning of sub-100 nm electron channels in MoS2 FETs. ; This work was funded by the European Union FP7/2007-2013 under Grant Agreement No. 318804 (SNM), the Ministerio de Economía y Competitividad (Spain) under Grant No. MAT2013-44858-R, the Marie Curie ITN network "MoWSeS" (Grant No. 317451) and the Swiss SNF Sinergia Grant No. 147607. ; Peer Reviewed

Vertically stacked two-dimensional (2D) heterostructures composed of 2D semiconductors have attracted great attention. Most of these include hexagonal boron nitride (h-BN) as either a substrate, an encapsulant, or a tunnel barrier. However, reliable synthesis of large-area and epitaxial 2D heterostructures incorporating BN remains challenging. Here, we demonstrate the epitaxial growth of nominal monolayer (ML) MoSe2 on h-BN/Rh(111) by molecular beam epitaxy, where the MoSe2/h-BN layer system can be transferred from the growth substrate onto SiO2. The valence band structure of ML MoSe2/h-BN/Rh(111) revealed by photoemission electron momentum microscopy (kPEEM) shows that the valence band maximum located at the K point is 1.33 eV below the Fermi level (EF), whereas the energy difference between K and Γ points is determined to be 0.23 eV, demonstrating that the electronic properties, such as the direct band gap and the effective mass of ML MoSe2, are well preserved in MoSe2/h-BN heterostructures. ; The access was provided by the NFFA-Europe Infrastructure (proposal ID 121) under Horizon 2020 EU Funding Program. We thank N. Gambacorti for coordinating the access to the NFFA-EU program. This work was financially supported by the European Research Council (Grant No. 240076) and has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement Nos. 696656 and 785219 (Graphene Flagship Core 1 and Core 2). M.P. acknowledges support by the Swiss National Science Foundation (Grant No. 200021-162612). ; Peer reviewed