A surplus amount of oxygen is needed to produce titanium dioxide films by reactive electron-beam evaporation of Ti3O5. We investigated the ratio of the rates at which oxygen molecules and TiOx molecules impinge upon substrates at 25° and 250 °C to produce TiO2 films that show no optical absorption in the visible spectral region. On unheated substrates the ratio was 49, and at 250 °C it was 26, provided that the substrates had been exposed to air after being coated at the given substrate temperature. Higher ratios were required if the TiO2 film was covered with a SiO2 film, which impeded further oxidation. Furthermore, the postdeposition oxidation behavior of these films was studied.
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