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The goal of the conducted experiments was to evaluate if the increased density of the plasma in High Power Impulse Magnetron Sputtering (HiPIMS) argon discharge would give the possibility of obtaining diamond-like films with high sp3 fraction content at room temperature. The magnetron cathode was driven by the self-designed supply. It consisted of high voltage supply, tank capacitors and a set of switches. The tank capacitors and the inductances of connecting wires formed an LC resonant circuit. As a result, each sputtering pulse (duration of 20 μs, peak current of 1500–2200 A) was followed by the inverse pulse (duration of 25 μs, peak current of 400–700 A), both having a sinusoidal shape. The repetition time was 3 s. The silicon substrates were placed 8 cm above the target surface. The sputtering processes of 99.99% pure graphite target were conducted in argon atmosphere at a pressure of 6–8 × 10− 3 hPa. The carbon films obtained after 400 deposition pulses had a thickness of 35 nm. The surface RMS roughness, measured using an optical profiler, was about 2 nm. The refractive index was estimated by means of ellipsometric studies to be 2.45 and 2.3 at 400 and 800 nm, respectively. The sp3 hybridization fraction content of about 70–80% was calculated based on the analysis of Raman Scattering spectra.

In this work we present combined Kelvin probe force microscopy and Raman spectroscopy studies of supported and suspended structures formed out of chemical vapor deposition (CVD) grown graphene. Work function of both suspended and supported graphene was -4.81 ± 0.06eV and -4.92 ± 0.06eV respectively. By G and 2D modes correlation we showed, that CVD graphene was influenced by biaxial strain. Increased contact potential difference (CPD) on the suspended graphene in comparison with the areas of the supported graphene was the sign of increased strain (from 0.05% to ~ 0.12%) rather than decreased doping (p-doping decreased from ~ 5.5 × 1012cm-2 to ~ 4.5 × 1012cm-2).