LEE- Nano Bilim ve Nano Mühendislik-Yüksek Lisans
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ÖgeFormation and structural properties of water induced structures at graphene/mica and graphene/CrxO/glass interfaces(Graduate School, 2021-10-08) Novruzov, Orkhan ; Gürlü, Oğuzhan ; 513171019 ; Nano Science and Nano Engineering ; Nano Bilim ve Nano MühendislikWater behavior at interfaces has great importance. Especially molecularly thin layer water or nanoconfined water. Nanoconfined water properties are different from bulk ones. Studying nanoconfined water properties have fundamental importance in biology, material science, nanofluidics, tribology, and corrosion. Nanoconfiment materials are carbon nanotubes and layered two-dimensional materials or Van der Waals crystals. In this thesis, we studied water interaction behavior with graphene/water/CrxOy/glass and graphene/mica systems. For this purpose, we needed the following devices: Optic microscope with the isolated system, PVD system, graphene heater, and materials like CVD-grown graphene, muscovite mica, soda-lime glass, and chromium granulates. Firstly, we started with graphene/water/CrxOy/glass system. We did thermal evaporation of chromium using PVD system that was assembled in our laboratory. As a substrate, we used soda lime microscope slide glass(INTROLAB). Chromium thin-film on glass samples was produced. The thickness of thin-film chromium was varied. We transferred CVD-grown graphene onto chromium thin-film glass with the wet transfer method, then annealed it in a tube furnace around 450°C degrees under atmospheric ambient conditions for approximately 40 minutes. As soon as annealing finished we quickly transferred produced sample into a container full of silica gels to preserve from environmental humidity. We reduced humidity within enclosed boxes in which an Optical light microscope stayed for study samples under controlled humidification. We took optic data before, during, and after the humidification process. Secondly, our second system for research was graphene/water/mica. Again as in the graphene/water/CrxOy/glass system, we used CVD-grown graphene and V2grade muscovite mica(Ted Pella). Using scotch tape we cleavage mica several times then CVD-grown graphene was transferred onto it using the wet transfer method. We preserve graphene/mica samples in a container full of silica gels. We studied them with two methods: First under the optic microscope in the isolated box and second using the graphene heater. We reduced humidity to 9% in the isolated box using silica. In the case of the graphene heater, we managed to heat up nearly 200°C. We observed fractal in graphene/CrxOy/glass system but due to non-homogeneous deposition of chromium fractal formation was inconsistent. In case of graphene/mica system observation of de/rewetting process was not possible even though we reduce humidity. The graphene heater was functional, the reason that we couldn't use it was a poorer resolution of the graphene/mica system. Otherwise, observation de/rewetting graphene/water/mica with the optic microscope is challenging.