▎ 摘　　要

The thermoelectric properties of various graphene samples, including isotopically modified heterostructures grown by chemical vapor deposition, are investigated from the viewpoint of thermoelectric device applications. The thermoelectric power of graphene varies from -80 to 90 mu V K-1, depending on the applied gate voltage. Similar to typical metals and semiconductors, the thermoelectric power of graphene decreases as the electrical conductivity increases, regardless if isotopes are present. The results follow a line with a slope of -198 mu V K-1 in the Jonker plot, indicating that the maximum power factor is 5.29 x 10(-3) W m(-1) K-2 irrespective of carbon isotope modulation in graphene. Because limiting phonon propagation independent of the electric properties can reduce the thermal conductivity of graphene containing carbon isotopes and isotopic heterojunctions, introducing carbon isotopes into the graphene structure improves the thermoelectric figure of merit without affecting the power factor.