| Graphene patterning,i.e.,etching graphene film into certain micro/nano structures,is a significant step in fabricating graphene-based electronic,optoelectronic elements for both fundamental studies and industrial applications.In this thesis,we have for the first time proposed to pattern graphene film by magnetic-assisted UV ozonation based on the paramagnetic property of oxygen molecules/radicals.Firstly,we have explored the oxidation intensity for the micro-cleaved graphene film by UV ozonation under irradiation of a xenon excimer lamp.Analyses of the optical topography and X-ray photoelectron spectroscopy（XPS）indicate that its oxidation intensity with the oxygen content of～1.4Pa at room temperature exceeds that of high-temperature（120℃）UV ozonation under irradiation of a low-pressure mercury lamp.Secondly,we have successfully patterned chemical vapor deposition（CVD）grown graphene film by applying an approximately vertical magnetic field(BZ=0.31 T,?BZ=90 T?m-1)in UV ozonation.In this process,the paramagnetic oxygen molecules and photodissociated oxygen radicals are magnetized,and their random motions convert into directional which can greatly enhance the quality of graphene patterning.Using a ferromagnetic steel mask,we have patterned graphene with a line width of29μm and lateral under-oxidation less than 4μm by reducing lateral diffusion and dissipation of the randomly moved ozone molecules.We can modify graphene microstructures by tuning the mask and external magnetic field.Finally,the vertical magnetic-field-assisted UV ozonation has been successfully used to fabricate graphene field-effect transistor（FET）arrays with the hole and electron mobilities up to1682 cm2?V-1?s-1 and1316cm2?V-1?s-1,respectively.Magnetic-assisted UV ozonation can be a promising solution toward resist-free,substrate non-damaging,and cost effective microscale patterning of graphene film. |
