We report on the electrical characterisation and Raman spectroscopy of CVD copper-grown graphene transferred onto a Si/SiO 2 substrate by the high-speed (1mm per second) electrochemical delamination. We determine graphene's sheet resistance, carrier mobility and concentration as well as its physical quality as a function of the electolyte concentration. Graphene's electrical properties are investigated with standard Hall measurements in van der Pauw geometry and a contactless method that employs a single-post dielectric resonator operating at microwave frequencies.These properties are related to the widely used copper etching technique. The results prove that the high-speed electrochemical delamination provides good quality graphene within a short timescale.

We describe the fabrication and characterisation of a touch-mode capacitive pressure sensor (TMCPS) with a robust design that comprises a graphene-polymer heterostructure film, laminated onto the silicon dioxide surface of a silicon wafer, incorporating a SU-8 spacer grid structure. The spacer grid structure allows the flexible graphene-polymer film to be partially suspended above the substrate, such that a pressure on the membrane results in a reproducible deflection, even after exposing the membrane to pressures over 10 times the operating range. Sensors show reproducible pressure transduction in water submersion at varying depths under static and dynamic loading. The measured capacitance change in response to pressure is in good agreement with an analytical model of clamped plates in touch mode. The device shows a pressure sensitivity of 27.1 0.5 fF Pa−1 over a pressure range of 0.5 kPa–8.5 kPa. In addition, we demonstrate the operation of this device as a force-touch sensor in air.

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In this report, we demonstrate the preparation method of a multi-layer stack with a pre-defined number of graphene layers, which was obtained using chemical vapor deposition graphene deposited on a copper substrate and subsequently transferred onto a poly(methyl methacrylate) (PMMA) substrate. The prepared multi-layer stack can also be transferred onto an arbitrary substrate and in the end, the polymer can be removed, which in consequence significantly increases the range of possible graphene applications. The multi-layer character was confirmed by optical transmittance measurements and Raman spectroscopy, whereas the microstructure of the multi-layer graphene stack was investigated using Scanning Electron Microscopy. The electrical properties in the function of the number of graphene layers were assessed with standard Hall Effect measurements. Finally, we showed the practical application of the multi-layer graphene stack as a saturable absorber of a mode-locked Er-doped fiber laser.