The Design, Construction and Use of a Low-Temperature, Ultra High Vacuum Scanning Tunneling Microscope for Reaction Studies

Scanning tunneling microscopy studies preformed at room temperature have provided insight as to how local structure of monolayers and gas-radicals react with one another. Previous experiments with hydrogen atoms show that surface morphology plays a large roll in how the reaction proceeds. We examined the reaction with chlorine–gas radicals and observed that, while surface morphology plays a role, the reaction mechanism differs in that the closed-packed regions of the monolayer are most reactive. However, thermal impacts on the surface do not allow for the direct observation of reactions as they proceed. To remedy this, a low-temperature, ultrahigh vacuum scanning probe instrument designed to preform the same reaction studies has been built utilizing 3D-printed components. Prior to 3D-printed metals being used in the LT-UHV instrument, they were used in a ambient-condition design that was vibrationally stable without the use of external isolation or dampening, and the 3D-printed metals were determined to be compatible with UHV.