Photolysis-laser-induced fluorescence diagnostic for GaCI

A spatially resolved optical diagnostic for GaCl is described. The technique uses 248-nm excimer laser radiation to photolyze GaCl and also to excite fluorescence in the resulting gallium atoms. This yields gallium fluorescence at 245, 266, 287, 294, 403, and 417 nm. The method is specific to GaCl(3) and is not affected by the presence of a GaCl3 precursor. Gallium fluorescence is linear in both the GaCl partial pressure and the laser energy under specified conditions. The photophysics of this process are contrasted to related GACl studies of dissociative excitation at 193 nm.