چكيده به لاتين
Hybrid nanostructures have gained considerable interest during the last decades. The electronic properties of these hybrid nanostructures are determined by their edge and interface patterns and have a variety of applications, including integrated circuits, spinronics, medical physics and molecular sensors. Hence, in the first part of this thesis, We investigate the electronic transport properties of two types of junction based on single polyaromatic hydrocarbons (PAHs) and PAHs embedded in boron nitride (h-BN) nanoribbons, using nonequilibrium Green’s functions (NEGF) and density functional theory (DFT). In the PAH junctions, a Fano resonance line shape can be clearly seen at the Fermi energy in the transport feature. In hybrid junctions, structural asymmetries enable interactions between the electronic states, leading to observation of interface-based transport. Our findings reveal that the interface of PAH/h-BN strongly affects the transport properties of the structures. Also, increasing the voltage makes a big difference to the current among the ZGNR, non-hybrid cases and h-BN-molecule hybrids. Such behavior is also seen in the low bias region due to the broken symmetry and accumulation of positive and negative charges. Furthermore, we have examined different hybrid graphene/hBN nanogap, to assess whether or not this setup could be useful for distinguishing DNA nucleobases from each other. To this end, we theoretically study the electronic transport properties of different hybrid structure nanogaps as an electrode for sensing single nucleobases under ab-initio calculation. Our results show that hybrid nanogaps with boron interfaces shift the HOMO toward the Fermi energy leading to a better transmission coefficient in the vicinity of the Fermi energy level. In addition, nanogaps with boron interfaces and narrower graphene nanoroads enhance the sensitivity at and around the Fermi energy level for all nucleobases, especially for small ones.
At the end, The electrical conductance of hybrid monolayer graphene/h-BN ribbon with zigzag edges is numerically studied using density functional theory. Our findings reveal that transmission of graphene/h-BN hybrid structure is sensitive to the arrangement of its component.
