Mechanism of hydrogen promotion of field ionization and a new atom-probe field-ion-microscope experiment

Abstract

It is found that at the field strength where hydrogen promotion of field ionization occurs, the field-ion-microscope image spots flicker. This leads us to interpret the promotion effect as a field-ionization enhancement by the field adsorption of hydrogen at the apex of imaged surface atoms. A time-of-flight atom-probe experiment confirms this interpretation.