Investigation of the surface photochemical basis for metal film nucleation in laser chemical vapor deposition

Abstract
We report the results of ultraviolet irradiation of monolayers of organoaluminum complexes adsorbed to sapphire. Using surface vibrational spectroscopy, the compositional and structural changes caused by 248 and 193 nm surface illumination are documented. Electronic photochemistry of adsorbed trimethylaluminum is observed and can lead to nucleation of aluminum on the surface. A strong wavelength dependence to this process is observed which cannot be explained by assuming photochemical yields to be proportional to previously measured surface absorption cross sections. The implications for laser chemical vapor deposition of spatially localized metallic features are discussed.