Monolayer graphene (1LG) is frequently unpredictably modified by supporting material so that it limits development of devices. Van der Waals interaction is dominant in the models describing the in-plane processes, including the electrical charge transport. However, the current flow perpendicular to the plane of the graphene is still less understood. This report analysed specific aspect of the perpendicular current and disclosed an original way to create transport bridges perpendicular to the plane across the 1LG. The most extraordinary finding is that the electron transport between two parallel metal surfaces can be shut down and opened if the metals are separated by the 1LG. The electron transmission can be intentionally varied in this metal – 1LG – metal (M-G-M) system by pressure. In the experimental study the AFM force curve and tunnelling current measurements were combined when the external load force (0 – 1200 nN) and electrical potential (-1.5 V – +1.5 V) were used. It is proved that for low voltages (< ±9 mV) a bridge is opened perpendicular to the graphene across the M-G-M systems by the external force, if the compression dependent Fermi level crosses electronic states in the interfaces and graphene. The localised bridges with diameter about 10 – 40 nm can be opened and kept continuously by the stabilised force in separated points of the system. However, the predictable changes can be produced in the system if the voltage and the force exceeded critical magnitudes. A combined model was proposed acceptable to explain the bridging and predictably modify the characteristics.

Fabrication of practical devices based on the transient metal dichalcogenides (TMDs) can be successively extended to various areas of the applications if the large area growth technology can be intentionally controlled and the characteristics of the layers can be easily predicted. In present work we presented the principles of the technology control based on the single key variable that can be directly related to the sequence of the technological processes. The atomically thin MoS2 layers were used as a model material and the layers were obtained by the CVD synthesis of the molybdenum precursor. Our thorough study demonstrated that the method allowed to deliberately choose the number of the MoS2 two-dimensional (2D)-layers between 1 and 10 by simply choosing the precursor deposition time. The optical properties of the layers were characterised by the optical transitions that corresponded to the known band structure of the MoS2 layers. Fused calibration diagram was proposed as the practical tool for the technology control and it was proved to be highly successive in relating the 2D-properties of the films with the initial stage of the fabrication technology. The method can be adapted to the wafer size TMDs growth on the diverse substrates.

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Annealing is well known technique to improve metal contacts. In order to anneal metal/graphene contacts information of suitable time of thermal treatment process is required, otherwise in a long annealing process undesired deformation in graphene layer or electronic device can be induced. In this article we introduce the investigation of the annealing time of metal/graphene structure. Electrical properties of contact between CVD grown graphene and metal (Au and Ni), using circular transmission line model (CTLM) contact geometry is observed. Raman spectroscopy is applied for characterization aiming to clarify surface and interface properties. It is found that the effective contact formation occur after 4 min annealing. The increase of thermal treatment time leads to unwished effects in graphene layers.

Metal – graphene – metal stacks (M-G-M) suggested new specific ways for an integration of the two-dimensional (2D) materials into the three-dimensional (3D) electronic devices, such as transistors, supercapacitors, memristors and other. Intentional control of the local electronic properties in the stacks is the primary problem to be solved when developing the hybrid structures with 2D and 3D elements. For this, the physical mechanisms and the processes that define the properties of the stacks must be thoroughly understood. This report introduced an approach based on the force curve analysis in the terms of the interface characteristics in the M-G-M stack. In the study, the stack was produced by pressing platinum probe of Scanning Probe Microscope (SPM) to the surface of gold supported graphene monolayer and the force curve was measured under applied dc-voltage. Based on the model of the van der Waals contact, the equilibrium interface distances and the built-in potential were obtained from the experimental results. The equilibrium state was proved weakly dependent on the applied voltage below a threshold level. Above this level, irreversible changes and effect of the history of the tests were detected. The proposed method was acceptable to quantitatively describe the most essential characteristics in a local area of the M-G-M stack, essential for construction of nano-scaled electronic devices.