The thesis covers a broad range of electronic, optical and opto-electronic devices and various predicted physical effects. In particular, it examines the quantum interference transistor effect in graphene nanorings; tunable spin-filtering and spin-dependent negative differential resistance in composite heterostructures based on graphene and ferromagnetic materials; optical and novel electro-optical bistability and hysteresis in compound systems and the real-time control of radiation patterns of optical nanoantennas. The direction of the main radiation lobe of a regular plasmonic array can be...