We study the structure and electronic and optical properties of low-dimensional, nano-scale systems; examples of such systems include carbon nanotubes, graphene nanoflakes and nanowires.  Recent advances in this field include the production of single layers of metal-dichalcogenides (like MoS₂, WSe₂, etc.) which have semiconducting character, and their combination with graphene (a semi-metal) or hexagonal boron nitride (h-BN, an insulator) layers.