Nanogap multi-electrode atom and conductivity prober

We report on a nano-prober system that can image atoms, and also measure the surface electrical conductivity with multiple probes with <;100nm spacing, a capability that allows mapping of electrical conductivity of atomically thin films. Investigating nanoscale properties of atomically thin two-dimensional films such as graphene require precision control of sensing electrodes over atomic dimensions. Atomic probing is conducted using microfabricated probes in Scanning Tunneling Microscopy (STM) or Atomic Force Microscopy (AFM) mode, where the probes are navigated using PZT actuators and carrying out mechanical or electrical measurements, leading to a bulky actuator. AFM and STM allow conductivity measurements through the tip and the film, they do not allow measurement of conductivity on the film surface. The size of the tip handling actuation prevents two tips to be placed within a few tens of nanometer apart for nanoscale conductivity measurement. In this paper, we demonstrate nano-tip arrays for probing with integrated electrostatic actuators for measurement of surface conductivity. We have used our system to measure surface conductivity of HOPG substrate, measuring a conductivity of 0.4 Ω/nm², with a tip gap of 300 nm.