A high-pressure scanning tunneling microscope

We present the design and performance of a high-pressure scanning tunneling microscope (HP-STM), which allows atom-resolved imaging of metal surfaces at pressures ranging from ultrahigh vacuum (UHV) to atmospheric pressures ( 1 x 10(-10)-1000 mbar) on a routine basis. The HP-STM is integrated in a go ld-plated high-pressure cell with a volume of only similar to0.5 l, which i s attached directly to an UHV preparation/analysis chamber. The latter faci litates quick sample transfer between the UHV chamber and the high-pressure cell, and allows for in situ chemical and structural analysis by a number of analytical UHV techniques incorporated in the UHV chamber. Reactant gase s are admitted to the high-pressure cell via a dedicated gas handling syste m, which includes several stages of gas purification. The use of ultrapure gasses is essential when working at high pressures in order to achieve well -defined experimental conditions. The latter is demonstrated in the case of H/Cu(110) at atmospheric H-2 pressures where impurity-related structures w ere observed. (C) 2001 American Institute of Physics.