F. Stepniak

KxC60 : nonequilibrium thin film growth and spectroscopic results

Abstract This paper examines the electronic structure of the K-C 60 system. High resolution photoemission results show multiple phase formation, even for stoichiometries close to nominal single phase fields. The results are interpreted in terms of the nonequilibrium conditions for growth by vapor phase deposition.

Visible-light-induced oxidation for O2 on GaAs(110) : the role of hot electrons

Irradiation with 1.7 and 1.97 eV photons of O2 physisorbed on GaAs(110) at 25 K induced strong surface oxidation. The oxidation rate was dependent on photon energy as well as substrate doping type. The 1.97 eV photons induced reaction ∼30 times faster than did the 1.7 eV photons. For fixed photon energy, reaction on p‐type substrates was ∼6 times faster than on n‐type substrates. These results stand in contrast from those of room temperature experiments where reaction rate was independent of doping type and the dependence on photon energy reflected only the substrate photon absorption coefficient. We show that photoexcited hot electrons are responsible for photo‐induced reactions at low temperature. Coupling between hot electrons and physisorbed O2 is via resonant tunneling involving the O2 electron affinity level.