Thermoelectric Properties Of Zigzag Graphene Nanoribbons

With the research of new materials and the development of nano-technology, nano-sized de-vice has become a focus in the research of materials scientists. Owing to the dimension and quan-tum effects in mesoscopic systems, new materials in nanoscale devices exhibit novel electrical, thermal and thermoelectric properties. These novel properties have attracted more and more at-tention from researchers in experimental and theoretical studies, which shows that the materials possess a potential application value. In the work, we study the thermoelectric properties in zigzag graphene nanoribbons by applying the Landauer-Buttiker transport theory and the nonequilibri-um Green’s function method. We discuss the electronic and thermal transport in zigzag graphene nanoribbons and obtain some important conclusions.First of all, we study the thermal transport properties of phonon in zigzag graphene nanorib-bons by using Green’s function method. The result indicates that the width of zigzag graphene nanoribbons plays an important role in determining heat transport properties.Then we study the electronic transport properties of zigzag graphene nanoribbons according to the Landauer—Buttiker formulism. The result shows that both electronic conductance and ther-mal conductance increase as the width of zigzag graphene nanoribbons increases. However, both of them are constant while the length of zigzag graphene nanoribbons changes. When the temper-ature is raised, the electrical conductance is invariant, whereas the electronic thermal conductance increases.On the basis of the above work, we further study the thermoelectric properties of zigzag graphene nanoribbons. The results indicate that with the increase in the width of zigzag graphene nanoribbons, thermoelectric merit ZT will decrease. When the temperature rises, thermoelectric merit ZT increases a little. Thermoelectric merit ZT remains the same as the length of zigza-g graphene nanoribbons changes. These results suggest that the reduction in width of zigzag graphene nanoribbons and modulation of the temperature can effectively improve the thermoelec-tric merit of zigzag graphene nanoribbons.