Graphene quantum dots embedded in a hexagonal BN sheet: identical influences of zigzag/armchair edges.

Various graphene quantum dots (GQDs) embedded in a hexagonal BN sheet were studied theoretically using the tight binding model. The effective mass was analyzed as a function of the distance between neighboring GQDs. It was found that the effective mass increases exponentially as the distance increases, indicating that the confined states of GQDs are well conserved in these hybrid systems. Further studies revealed that a ubiquitous gap of 0.3-3 eV exists, the size of which is mainly governed by the GQD's dimensions whereas it is insensitive to edge structures. These results show that GQDs in BN are promising candidates for optoelectronics.