Fast- scanning tunneling microscope (Fast-STM)
Nowadays, Scanning Tunneling Microscopy, “STM”, is used widely, and is considered as one of the most powerful and effective instruments to investigate the structure of materials at the nanoscale. The Fast- STM is a commercial instrument STM 150 Aarhus from Specs Surface Nano Analysis company. By using the fast - STM, we don’t only measure the samples at ultrahigh vacuum, “UHV”; with a base pressure of 10-10 mbar range, which is created by pumpingsystems, but also at variable temperatures between 90K and 400K. Beside that, the fast - STM has 1,000,000 pixels / sec - scan speed and 1500nm x 1500 nm – scan range[1].
Moreover, the fast-STM has three chambers, corresponding to loadlock chamber, main chamber, and molecular chamber. The loadlock chamber is used for transfering the samples from outside to inside of the chamber. The main chamber is used for preparing samples, such as annealing and sputtering, and for scanning the sample surface. The molcular chamber is used for preparing different atoms and molecules to deposit them on the surface of the samples.
To sum up, the fast STM allow us to find out the topological structures of the samples and identify the properties of those systems. With this powerful tool, many interesting aspects of surface science are waiting for you to discover in the future.
Projects currently followed at this machine are:
a. Structure formation in heteroepitaxial systems: Co on Ag/Cu/Au.
b. Diffusion of single vacancies on fcc surfaces at low temperature.
c. Diffusion of very small clusters in homoepitaxial systems produced by Laser ablation.
Fig. Fast-STM