The growth of graphene on SiC/Si substrates is an appealing alternative to the growth on bulk SiC for cost reduction and to better integrate the material with Si based electronic devices. In this paper, we present a thorough in-situ study of the growth of epitaxial graphene on 3C SiC (111)/Si (111) substrates via high temperature annealing (ranging from 1125˚C to 1375˚C) in ultra high vacuum (UHV). The quality and number of graphene layers have been investigated by using X-ray Photoelectron Spectroscopy (XPS), while the surface characterization have been studied by Scanning Tunnelling Microscopy (STM). Ex-situ Raman spectroscopy measurements confirm our findings, which demonstrate the exponential dependence of the number of graphene layer from the annealing temperature.

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We designed a nickel-assisted process to obtain graphene with sheet resistance as low as 80 Ω square(-1) from silicon carbide films on Si wafers with highly enhanced surface area. The silicon carbide film acts as both a template and source of graphitic carbon, while, simultaneously, the nickel induces porosity on the surface of the film by forming silicides during the annealing process which are subsequently removed. As stand-alone electrodes in supercapacitors, these transfer-free graphene-on-chip samples show a typical double-layer supercapacitive behaviour with gravimetric capacitance of up to 65 F g(-1). This work is the first attempt to produce graphene with high surface area from silicon carbide thin films for energy storage at the wafer-level and may open numerous opportunities for on-chip integrated energy storage applications.

An easy transfer procedure to obtain graphene-based gas sensing devices operating at room temperature (RT) is presented. Starting from chemical vapor deposition-grown graphene on copper foil, we obtained single layer graphene which could be transferred onto arbitrary substrates. In particular, we placed single layer graphene on top of a SiO/Si substrate with pre-patterned Pt electrodes to realize a chemiresistor gas sensor able to operate at RT. The responses to ammonia (10, 20, 30 ppm) and nitrogen dioxide (1, 2, 3 ppm) are shown at different values of relative humidity, in dark and under 254 nm UV light. In order to check the sensor selectivity, gas response has also been tested towards hydrogen, ethanol, acetone and carbon oxide. Finally, a model based on linear dispersion relation characteristic of graphene, which take into account humidity and UV light effects, has been proposed.

Large-scale production of reliable carbon nanotubes (CNTs) based gas sensors involves the development of scalable and reliable processes for the fabrication of films with controlled morphology. Here, we report for the first time on highly scalable, ultrathin CNT films, to be employed as conductometric sensors for NO 2 and NH 3 detection at room temperature. The sensing films are produced by dip coating using dissolved CNTs in chlorosulfonic acid as a working solution. This surfactantfree approach does not require any post-treatment for the removal of dispersants or any CNTs functionalization, thus promising high quality CNTs for better sensitivity

The expanding development of portable electronic devices and ubiquitous sensing systems has created a strong demand for efficient miniaturized energy storage units, with planar geometries and capable of being integrated on a silicon platform. Generally, the performance of thin-film storage devices, including using graphene, is dramatically limited by their low surface area for ion-exchange. We had recently shown that a higher number of graphene layers does not translate into higher storage performance. Here we show a way to overcome this limitation and achieve a maximum accessible area for ion exchange. A repeated graphitization strategy using a nickel catalyst on epitaxial silicon carbide films on silicon yields few-layers graphenic nanocarbon electrodes with prominent edge defects, facilitating the intercalation between multiple graphenic sheets while maintaining overall a high electrode conductivity.

In this paper we clarify the transformation mechanism of 3C-SiC into graphene upon thermal decomposition, by a combination of high resolution Scanning Tunneling Microscopy (STM) images and first principle calculations. We studied the transition from 3C-SiC to graphene by high temperature annealing of C-terminated 3C SiC(111)/Si(111) samples in Ultra High Vacuum. By using STM we were able to observe * × 3) 30° structure due to its incommensurability with the 3C-SiC(111) lattice.