The polymerization of ethylene on surfaces sequentially dosed with TiC14 and trimethylaluminum was studied by Fourier transform infrared spectroscopy. The polymer film was observed in situ as a function of time and under the influence of 254-nm cw radiation. The rate of polymerization and the saturation thickness of the polyethylene are strongly dependent on the order of dosing and the partial pressures of the reactants that form the catalyst. UV enhancement of polymerization was demonstrated to occur through two separate photochemical channels: gas-phase photolysis of the reactants and solid-phase chemical transformation of a noncatalytic thin film.

Electron-beam-induced changes in the structure of partially amorphous CdS surfaces have been observed directly by atomic-resolution electron microscopy. A sequence of atomic rearrangements leading to nucleation and growth of cubic CdS and hexagonal Cd has been documented. Inelastic electron collisions lead to crystallization of overlying amorphous CdS material whereas electron-stimulated desorption of S from the underlying CdS crystal results in precipitation of Cd crystallites at the crystalline/amorphous interface. From 100 to 500 keV the events are almost energy-independent.

Laser-direct-writing processes are employed to fabricate a GaAs digital integrated circuit. The lithography-free techniques deposit and etch conductors and resistors, and remove insulating layers, thus enabling multilevel interconnections. These combined directwrite processes provide the flexibility of clip-lead prototyping on a micrometer scale.