Scanning Tunneling Microscopes

A Scanning Tunneling Microscope is a device which is capable of atomic resolution, and was the subject of a Nobel Prize for IBM researchers who first demonstrated the operating principle in the early 1980s.  Machines which use this principle are now found in most materials technology and life sciences institutes and companies worldwide.

However, researchers in materials technology frequently need to provide particular environments for their samples while taking STM images.  In particular, it is often required to alter the temperature of the sample, and ensure an ultra-high vacuum to maintain atomic-level cleanliness of the sample surface.

Working with Oxford Instruments, we provided both team and project management and key technical innovation which led to the introduction of two products. 

The first of these was a variable-temperature STM, incorporating both a cryostat and a sample heater to enable the temperature to be varied from 20K to 1000K.  All piezo-electric positioners in the design were at room temperature.  Technical innovation was provided in the anti-vibration system and the thermal design to meet the overall design goals.  The core of the STM design was established through collaboration between WA Technology and the FOM Institute.

The second STM was a low-temperature machine, capable of cooling to 6K in UHV.  The key difference as compared to the VTSTM above was the need to select an area to be scanned anywhere in a 6mm square.  Also, all the piezo-electric positioning systems were at 6K or lower to ensure an isothermal environment for the sample.  These constraints (i.e. the coarse positioning and isothermal specification) placed on the design led to an extremely cramped parameter space in terms of design philosophy and materials choice.  Team recruitment and leadership, and key innovation was provided in the anti-vibration and cooling systems to provide a system which met all the design goals.