University of Cambridge Techniques Surface Science Group Home Department of Chemistry University of Cambridge

Scanning Tunnelling Microscopy (STM)

Introduction

The scanning tunnelling microscope (STM) allows us to record real-space images of surfaces at atomic-scale resolution. We can look at long-range-ordered structures, including those with large unit meshes (such as coincidence-site lattices), but we can also look at defects (such as vacancies, steps and impurities), and at disordered regions. With the right conditions, we can image single molecules adsorbed on the surface. At lower resolution, we can look at morphological features, such as faceting, or epitaxial growth modes (e.g. island formation).

Our STM Apparatus

Our STM is an Omicron low-temperature (LT) STM. It employs a double bath cryostat, allowing us to work at 5 K or at 77 K, as well as at room temperature. It is housed in a UHV system with standard facilities for surface preparation and characterisation, including LEED, AES, a mass spectrometer, and a metal evaporator. The STM is equipped with a pulsed laser system, which allows surface heating over a very short timescale (~10 ns) to be attained, enabling us to make "musical chairs" movies of surface diffusion. We can also dose gases directly onto the surface at low temperature in the STM.


[Viewable With Any Browser] [Valid HTML 4.01 Transitional]


Last updated 25/4/2009 by mb633 -at- cam.ac.uk