Design of Motorized Coarse Positioning System for Cryogenic Scanning Probe Microscope

The ability to investigate quantum properties of electrons in graphene nanostructures allows insights into the behavior of quantum particles and possible applications in future quantum based electronic devices. We designed a low-cost cryogenic Scanning Probe Microscope to image electrons in graphene. One of the challenges in such cryogenic microscopy is the design of coarse positioning system that allows to find the sample at cryogenic temperatures. Our design involves locating the sample through a motorized coarse positioning system mounted to a tabletop cryostat. The components of the microscope are made using a variety of different techniques including 3D printed and CNC milled parts. The designed coarse positioning system operates using separate motors which move the sample in x,y,z directions until the signal is detected by the piezo tube. Two rods with grooves in opposing directions made using CNC milling techniques prevent the platform holding the sample from rotating as it moved to the piezo tube by measuring changes in resistance. This design allows for faster turnaround time for imaging experiments such quantum devices and results in cost savings in terms of cryogenic usage.