Quantum-dot states and optical excitations in edge-modulated graphene nanoribbons

We investigate from first principles the electronic and optical properties of edge-modulated armchair graphene nanoribbons, including both quasi-particle corrections and excitonic effects. Exploiting the oscillating behavior of the ribbon energy gap, we show that minimal width modulations are sufficient to obtain confinement of both electrons and holes, thus forming optically active quantum dots with unique properties, such as cohexistence of dot-like and extended excitations and fine tunability of optical spectra, with great potential for optoelectronic applications.