| Abstract [eng] |
In this doctoral dissertation, the direct horizontal synthesis of graphene on catalytic-free substrates (Si, SiO₂, Al₂O₃(0001), and h-BN/SiO₂) commonly used in microelectronics and optoelectronics is investigated using microwave plasma-enhanced chemical vapor deposition (MW-PECVD). A steel protective cap was successfully implemented in this work to reduce the undesirable plasma effects on the substrate and the growing film. Utilizing Raman spectroscopy and atomic force microscopy (AFM), the influence of synthesis parameters (gas flow ratio, pressure, and temperature) on the morphology, defect density, and structure of nanocrystalline multi-layer graphene films was determined. Furthermore, the critical lower-temperature limits (<600 °C) for synthesis were defined, opening new pathways for the integration of graphene into standard CMOS technology. Furthermore, the suitability of the directly grown graphene for electronic device fabrication was demonstrated. The functional properties of the developed graphene/Si photodiodes and biological sensors operating on the graphene field-effect transistor (G-FET) principle were investigated. It was found that the insertion of a dielectric hexagonal boron nitride (h-BN) underlayer doubles the short-circuit current and photocurrent of the photodiodes due to reduced surface carrier recombination, while the fabricated biological sensors exhibit high sensitivity. |
