Electron Irradiation Induced Chemical Vapor Deposition of Titanium Chloride on Gold and on Magnesium Chloride Thin Films. Surface Characterization by AES, XPS, and TPD^§

The electron irradiation induced TiCl4 deposition on a gold polycrystalline foil and on a Au (100) single crystal in ultra-high vacuum conditions is reported. Titanium chloride ultrathin films are prepared at 250−300 K by irradiation of the substrate with 1 keV electrons in a background pressure of TiCl4 of 1 × 10-8 to 5 × 10-7 Torr. The deposited films are characterized by AES, XPS, and temperature-programmed desorption (TPD). We can grow titanium chloride films of the maximum thickness of about 25 Å under our experimental conditions. The film consists of 3−4 layers of TiCl2 with 1 monolayer of TiCl4 chemisorbed on its surface. A comparison is made with the titanium chloride film grown on MgCl2 ultrathin films by electron irradiation induced TiCl4 deposition as previously reported. This film is very similar to the titanium chloride film deposited on Au and can be described as few layers of TiCl2 deposited on a defective MgCl2-x film. One monolayer of TiCl4 is chemisorbed on the TiCl2 surface.