Laser photolysis and ionization of polyatomic molecules: Film growth and spectroscopic diagnostics

Experiments are described in which semiconductor or metal films are grown from the vapor phase by photodissociating or photoionizing diatomic or polyatomic molecules. The photolysis of GeH₄ at 248 nm (hw = 5 eV) is initiated by a two photon process that liberates the germylene radical GeH2. Spatially and temporally-resolved concentration profiles for several excited states of GeH and atomic Ge have been measured near the substrate. Thin indium films have been deposited on nickel substrates by dissociatively ionizing indium monoiodide (Inl) to produce In⁺ - I^- ion pairs. The dynamics of ion pair production for thallium iodide or Inl vapor photoexcited at 193 nm have been studied by combining an excimer laser with microwave absorption techniques.