In this seminar, I will present our recent works on electronic properties and devices applications of carbon based materials, especially graphene and carbon nanotubes.
We systematically investigated the mechanical, electronic properties of graphene, and the related device applications. We discovered interesting quantum effects of graphene edge stresses, which would in turn manifest in mechanical edge twisting and warping instability of graphene. We found the spin polarization of graphene nanoribbons could be suppressed by edge defect in impurities, indicating that practical realization of spintronics in graphene nanoribbons was rather challenging. We designed a series of field effect transistors based on patterned graphene. Besides graphene, we demonstrated that partially open carbon nanotubes observed in recent experiments have rich electronic and magnetic properties which depend on the degree of opening. Half-metallicity may be achieved and the spin current may be controlled by external electric field or chemical functionalization.