Comparative Mapping of the Local Potential of Graphene/hBN Systems Using Scanned Probe Techniques

Mapping the local electrostatic potential of 2D materials is an important step in understanding how defects and strain affect local electrostatic structure. Potential mapping can also reveal the strength of el-el interactions in a material, and – when performed under transport conditions – can directly probe the nature of electronic flow. Specifically, probing the local potential gradient of a current-driven graphene sheet could provide insight into how electronic transport shifts between ballistic and diffusive regimes. We present preliminary results comparing three scanned probe methods for mapping electrostatic potential of a graphene sheet: Kelvin probe force microscopy (KPFM), scanning tunneling potentiometry (STP), and scanning tunneling spectroscopy (STS). We discuss the comparative advantages of each technique, describing how each method performs when measuring a graphene/hBN system with current applied in situ.