Low Cost Electronics Design for Cooled Scanning Probe Microscope Andrew Smeltzer, Dr. Sagar Bhandari Department of Physics and Engineering, Slippery Rock University

The ability to measure and manipulate electrons at the nanoscale gives insight into nanoscale physics and paves way for its applications in electronics and photonics. We present a design of the electronics for a scanning probe microscope that is cooled to 77K. Our design was created so that it is possible for smaller undergraduate facilities to replicate the design. The imaging technique relies on a conductive scanning tip that acts as a local, movable electrostatic gate. The tip creates a local change in density of electrons in the material directly underneath it, deflecting the electrons away from their original path. The conductance is measured as a function of tip position while the tip moves across the sample. The conductance change vs. tip position gives the map of the electron flow. A raspberry pi controls the microscope. The conductance value is converted to a voltage that is amplified and sent to the pi to be stored and used for feedback. The pi uses this feedback keep the tip at a constant height above the sample. The pi controls a piezoelectric tube to control the tip position during the scan. Scanning and collecting data is done using our own software. With this method, we plan to image the viscous flow of electrons in graphene at liquid nitrogen temperature.