Field Evaporation of Ge(111) Surfaces in Presence of Hydrogen

Abstract

Field evaporation of Ge(111) surfaces in the presence of hydrogen was studied by field ion microscopy. The evaporation rate decreased exponentially with decreasing field strength and increased almost linearly with increasing hydrogen pressure below 1?10-4 Torr, above which it tended to saturate. In the investigated temperature range, 80-274 K, the evaporation rate approached constant values below 100 K and above 170 K, while it increased exponentially with the reciprocal value of temperature in the range 100-170 K. The evaporation voltage was constant below 100 K and above 250 K, while it decreased linearly with increasing reciprocal value of temperature in the range 100-250 K. The process of field evaporation was discussed from the viewpoint of surface hydride formation and hydride desorption to explain the experimental results.