Study on uniquely modified diamond, diamond / B-SiC nanocomposite and graphene nitride (g-C3 N4) surfaces

Abstract

Diamond and diamond/β-SiC composite films are being widely studied for their wear resistant, structural and electronic properties. Of the various methods researchers use to modify the structure of these films, using irrradiation techniques in particular are of interest due to their versatility. This thesis work was carried out to: (i) understand the indentation damage and electrical properties of diamond/β-SiC nanocomposite thin films, (ii) modify (i.e., phase, structural and/or morphological) the diamond films by using ion beam implantation/irradiation technique, (iii) modify the surface morphology of g-C3N4 by using ion implantation/irradiation, (iv)Fabricate the metal-insulator-semiconductor active structures in diamond films. The forms of diamond and diamond/β-SiC nanocomposite films resulting from such modifications are investigated using Raman spectroscopy in conjunction with scanning electron microscopy and x-ray diffraction were carried out to understand the microstructure and phase information. Also as-grown diamond/β-SiC nanocomposite films are investigated with mechanical and electrical testing. The impact of these characterizations will provide the valuable perspective to researchers in materials science. Understanding the changes to the structure and properties of this class of thin films which can be induced through various mechanisms will allow future researchers to refine these films towards technological applications in areas of hard coatings, electronics and biosensing. Raman scattering experiments in conjunction with scanning electron microscopy and x-ray diffraction were carried out to extract microstructure and phase information of the gamma and nitrogen ion irradiated diamond thin film surfaces. The γ-irradiation of diamond films showed no phase, surface and structural changes. The nitrogen ion implantation with 100 keV results increase in sp2-C network in diamond films which leads to improve the surface conductivity of these films. This nitrogen ion implantation of diamond films fabricate the metal-insulator-semiconductor (MIS) active surfaces which are used in electronic device applications. The graphene nitride (g-C3N4) materials are used in energy applications. The silicon implanted/irradiated g-C3N4 showed sheet like morphology with stable phase and structure of graphene nitride which are used in lithium ion batteries applications.