Basic overview of the scanning tunneling microscope tip-sample interaction. When the tip is within atomic distance of the sample surface and a small bias voltage about a volt or so is applied, tunneling current can be measured. Adjusting the height of the tip while scanning the tip over the surface with a fixed bias voltage to always maintain a constant tunnel current will map out the sample topography.
A look into the Ultra High Vacuum (UHV) chamber of a UHV Scanning Tunneling Microscope (STM). Several grippers are mounted to move samples back and forth between the holder for multiple samples and the STM microscope which is the tubular gold capped structure held by a spring suspension.