Photolytic decomposition of adsorbed tellurium and cadmium alkyl species at 295 K upon 193 nm photon irradiation

Abstract

The photolytic decomposition of adspecies formed by the adsorption of tellurium and cadmium alkyls at 295 K under ultrahigh-vacuum conditions has been studied using x-ray photoelectron spectroscopy. Dimethyl tellurium adsorbed at submonolayer coverages on a polycrystalline gold substrate has been observed to undergo nearly quantitative photolytic decomposition at 193 nm to form metallic tellurium. The hydrocarbon photofragments produced in the decomposition lead to negligible carbon contamination on the gold surface. Dimethyl cadmium adsorbed on amorphous SiO2 both desorbs and decomposes to form the metal adspecies. In this case, most of the carbon remains as hydrocarbon and carbidic contaminants. Monomethyl adspecies of both metals formed on Si(100) and GaAs(100) surfaces are inactive with respect to decomposition at the low fluences (0.25 mJ cm−2) used in these experiments; however, substantial desorption is observed.