High-quality graphene can be produced in large scale by chemical vapor deposition (CVD). Ethanol is emerging as a versatile carbon source alternative to methane for the growth of graphene on a copper (Cu) foil catalyst. To date, rigorous studies of the ethanol-based process still lack, especially concerning the first stages of the growth, which ultimately determines graphene's properties, such as defect density and crystal size, and performance, such as electrical conductance and mechanical strength. In particular, so far the growth of isolated graphene grains by ethanol-CVD has been achieved only on preoxidized Cu foils folded in enclosures, in an attempt to limit the partial pressure of the precursor, and thus the nucleation rate. We systematically explored the process parameters of ethanol-CVD to obtain full control over the nucleation rate, grain size, and crystallinity of graphene on flat Cu foils, which are of interest for any realistic production in large scale. To limit the nucleation density and increase the grain size, preoxidized Cu foils (250 °C in air) were used as substrates, and the process parameters were thoroughly investigated and tuned. Ultimately, at an ethanol vapor flow of 1.5 × 10 −3 sccm the nucleation density reduced to less than 3 nuclei/mm 2 and isolated single-crystal grains grew with a lateral size above 500 μm. When transferred onto Si/SiO 2 substrates, these grains showed field-effect mobility beyond 1300 cm 2 /(V s). Our results provide a step closer towards an affordable commercialization of electronic-grade, large-area graphene.

Low‐dimensional carbon materials occupy a relevant role in the field of nanotechnology. Herein, the authors report a study conducted by atomic force microscopy and Raman spectroscopy on the deposition of carbon dots onto graphene surfaces. The study aims at understanding if and how the morphology and the microstructure of chemical vapor deposited graphene on Si/SiO2 may change due to the interaction with the carbon dots. Potential alteration in the graphene's electrical properties might be detrimental for optoelectronic applications. The deposition of carbon dots dispersed in water and ethanol solvents are explored to investigate the effect of solvents with different fluidic properties. The obtained results indicate that the carbon dots do not alter the quality of graphene.

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Schottky‐barrier solar cells (SBSCs) represent low‐cost candidates for photovoltaics applications. The engineering of the interface between absorber and front electrode is crucial for reducing the dark current, blocking the majority carriers injected into the electrode, and reducing surface recombination. The presence of tailored interfacial layers between the metal electrode and the semiconductor absorber can improve the cell performance. In this work, the interface of a graphene/n‐type Si SBSC by introducing a graphene‐based derivative (GBD) layer meant to reduce the Schottky‐barrier height (SBH) and ease the charge collection are engineered. The chemical vapor deposition (CVD) parameters are tuned to obtain the two graphene films with different structure and electrical properties: few‐layer graphene (FLG) working as transparent conductive electrode and GBD layer with electron‐blocking and hole‐transporting properties. Test SBSCs are fabricated to evaluate the effect of the introduction of GBD as interlayer into the FLG/n‐Si junction. The GBD layer reduces the recombination at the interface between graphene and n‐Si, and improves the external quantum efficiency (EQE) with optical bias from 50 to 60%. The FLG/GBD/n‐Si cell attains a power conversion efficiency (PCE) of ≈5%, which increase to 6.7% after a doping treatment by nitric acid vapor.

The presence of heavy minerals, including radionuclides such as 238U and 232Th, in the beach placers outcropping along the western Calabrian coast (South Italy) has been investigated in order to single out the contribution from natural sources to the total radiation level. Assessing the human health radiation risk for these areas is of great importance due to their main touristic destination. With the aim of characterizing the natural radionuclides contents of the Calabrian sands, the correlations existing between their mineralogical and geochemical features and those of the parent rocks have been studied by measuring the sand radionuclides concentrations and decay products and by calculating the outdoor effective dose rate. The radioactivity in the Calabrian beach sediments is for the most part attributed to monazite and, in turn, to the high amount of Th (in the 409–464 ppm range), and is a function of the rock types and of the formation processes. The outdoor dose and effective dose rates for an exposure period of three months are in the range 1045–1240 nGy/h and 0.32–0.37 mSv/y, respectively. Although these values are remarkably higher than the corresponding average world values, they fall within the limits fixed by the Italian legislation, assuming individuals that spend three summer months on the beach. The results obtained for this area of the Southern Italy coastlines can be used as a baseline for future investigations concerning radioactivity background levels, also in other regions. Moreover, the coupling of the present findings with those of epidemiological studies will allow gaining a better evaluation of possible health effects on the population.