AFM diagnostics of graphene-based quantum Hall devices

In this paper we present the results of morphological, mechanical and electrical investigation of the properties of prepared graphene flakes and graphene-based quantum Hall devices. AFM imaging allowed us to identify the local imperfections and unintentional modifications of the graphene sheets which had caused severe deterioration of the device electrical performance. Utilizing the NanoSwing imaging method, based on the time-resolved tapping mode, we could observe non-homogeneities of the structural and mechanical properties. We also diagnosed the device under working conditions by Kelvin probe microscopy and detected its local electric field distribution.

► Mechanical properties of graphene do not change with increasing number of layers. ► Kelvin probe microscopy is a suitable tool for graphene electronics diagnostics. ► High-resolution AFM imaging reveals device fabrication weaknesses.