A beetle-type scanning tunneling microscope for studies of nano-structured surfaces.

摘要

A beetle-type scanning tunneling microscope with linear approach mechanism was adapted for use at ultrahigh vacuum. A beetle was constructed and demonstrated atomic resolution in air. Electrical noise and grounding considerations were addressed and low-noise conditions were achieved. An in-situ electron-beam tip conditioning stage, designed to maximize electron flux at the apex and minimize superfluous piezo heating, was modeled, designed and tested. Protocols for field emission tip sharpening were devised and implemented; including control software and automatic Fowler-Nordheim assessment of sharpness. The vacuum system was reconfigured to maximize pumping conductance. A new manifold chamber and a manifold for the turbomolecular pump were designed and constructed to facilitate this. Sample transfer infrastructure, including transfer forks and a combined sample holder and table suitable for resistive heating of semiconductor samples, was designed and tested. A low-temperature capable scanning stage was designed and has proven to be exceptionally vibrationally stable. A resistive-heating stage for sample preparation has been thoroughly tested, and protocols for silicon sample preparation, including computer-controlled degas and sample flashing algorithms, were implemented. Results on graphite, gold on mica and silicon surfaces are presented along with several projects for future consideration.