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Grafen je zelo perspektiven material, ki kljub debelini enega ogljikovega atoma velja za enega najmočnejših materialov na svetu. Poleg tega je odličen prevodnik toplote in električne energije. Grafen se uporablja na različnih področjih, kot so bioinženiring, kompozitni materiali, nanotehnologija, shranjevanje energije, itd. Lahko ga sintetiziramo na več načinov, vključno z mehansko cepitvijo, epitaksijo na silicijevem karbidu, kemijsko redukcijo grafen oksida in rastjo na kovinskih substratih s kemijsko depozicijo iz parne faze (CVD). Namen te diplomske naloge je bila sinteza grafena s pomočjo CVD metode na nikljevem substratu in karakterizacija pridobljenega produkta s pomočjo vrstičnega elektronskega mikroskopa (SEM) in ciklične voltametrije (CV). V našem primeru smo za sintezo grafena uporabljali metodo hladne stene (ang. »cold-wall«), pri kateri se stene reakcijske komore niso segrele direktno z indukcijo in so prav tako ostale na precej nižji temperaturi v primerjavi z nikljevim substratom. Z uporabo SEM smo najprej odkrili, da smo namesto enoplastnega grafena sintetizirali večplasten grafen oz. grafit. Nato smo se lotili preučevanja površinske aktivnosti niklja z uporabo CV in odkrili, da ima žarjen nikelj boljšo površinsko aktivnost od žarjenega niklja, na katerem so grafenske plasti. Graphene is a very promising material that, despite the thickness of one carbon atom, is considered one of the strongest materials in the world. Additionally, it exhibits excellent thermal and electrical conductivity. Graphene finds applications in various fields such as bioengineering, composite materials, nanotechnology, and energy storage, among others. It can be synthesized using different methods, including mechanical exfoliation, epitaxial growth on silicon carbide, chemical exfoliation, and growth on metal substrates through chemical vapor deposition (CVD). The objective of this thesis is to synthesize graphene using the CVD method on a nickel substrate and to characterize the resulting product using a scanning electron microscope (SEM) and cyclic voltammetry (CV). In our study, we employed the cold-wall method for graphene synthesis, whereby the walls of the reaction chamber were not directly heated by induction and have remained at a significantly lower temperature compared to the nickel substrate. Using SEM, we first discovered that we had synthesized graphite instead of graphene. We then set about studying the surface activity of nickel using CV and discovered that annealed nickel has a higher surface activity than annealed nickel with layers of carbon atoms on it. |
