Resonant transport and negative differential resistance in the graphene and graphyne quantum dots

The electronic transport properties of graphene and graphyne quantum dots embedded in zigzag-edged graphene nanoribbons are studied. The results show that the quasi-bound states in the quantum dots induce resonant transmission around the Fermi level in the transmission spectrums. While the resonant peaks lead to robust negative differential resistance (NDR) behaviors. Moreover, the resonant transmission and NDR behavior are very sensitive to the size of the quantum dots. As the size of quantum dots increases, the number of resonant peaks increases and shift to the Fermi level, correspondingly the NDR phenomena shift to lower bias. Compared with graphene quantum dots, graphyne quantum dots show more amazing transport properties. These interesting findings could offer useful guidelines for the design of electronics associated with resonant and NDR phenomenon.