Production of gallium atoms by excimer laser photolysis of trimethyl gallium

The gas phase kinetics of group III elements such as gallium are important in possible chemically driven energy transfer lasers and in chemical vapor deposition processes in the electronics industry. Excimer laser photodissociation of volatile gallium compounds via multiple photon process provides, a convenient room temperature source of gallium atoms for studying laser photolysis-laser induced fluorescence techniques. Preliminary results of the multiple photon dissociation of trimethyl gallium at 193 nm are reported. The time histories of the ground state and the metastable were measured by laser induced fluorescence. The resulting time profiles are complicated even in the absence of a reactant gas by the apparent production of ground state gallium at relatively long times after the excimer laser pulse. Possible mechanisms for this are investigated. It is indicated that the photodissociation of trimethyl gallium at 193 nm is complex.