Thermal annealing effect on the electrical quality of graphene/hexagonal boron nitride heterostructure devices

The development of the dry transfer method provides an abundant platform to construct various heterostructures of two-dimensional materials. However, the surface and interface cleanliness are essential to realize high electronical performance of heterostructures devices. Here, we demonstrated thermal annealing effect on the mobility and electrical transport properties of graphene on hexagonal boron nitride heterostructures devices. With different annealing temperature recipes for graphene on hexagonal boron nitride devices, we found annealing temperature at 300 °C can clean resist residual and achieve high mobility. Atomic force microscopy results also present a clean surface and small average root mean square roughness as low as 210 pm. Well defined oscillations and plateaus of electrical transport at low magnetic field indicate a high-quality graphene surface. (paper)