Electronic surface changes induced in silicon by hydrogen, oxygen, and cesium coverages

Abstract

The electronic surface state changes for low-energy cesium ion deposition, oxygen, and hydrogen adsorption on Si(100) are investigated. The change in surface potential (work function) is probed by electron reflection. This shift is then calibrated using photoemission onset measurements. The surface states are examined using ultraviolet photoemission spectroscopy (UPS). Results indicate that low work function surfaces attained previously by cesium and oxygen vapor deposition techniques are also attainable by ion bombardment. Results of work function and UPS measurements of atomic hydrogen adsorption are consistent with an asymmetric dimer model for the clean Si(100) surface. Atomic hydrogen adsorption on a cesiated and oxygenated surface has little effect on the work function, indicating that these surfaces may be viable in an actual dynamic negative hydrogen ion source.