A study of the infrared absorption spectra of thin amorphous films of molybdenum trioxide

Abstract

The spectra of thin amorphous films of MoO3 deposited by vacuum evaporation have been studied within the spectral range 4000-400 cm-1 by the Fourier transform infrared technique. Some samples in the thickness range 100 to 400 nm were investigated at room temperature. Four samples were investigated in the substrate deposition temperature range 293 to 543 K. Some samples were annealed in vacuum in the temperature range 473 to 673 K and their IR spectra were recorded as soon as the samples were cooled to room temperature. It has been observed that annealing of the samples at 473 K or above and also heating the substrates in the temperature range 473 K or above, results in the formation of molybdenum species of lower oxidation state than the normal Mo(VI), i.e. Mo(V). This new oxidation state is formed by electron transfer from the oxygen 2p to the molybdenum 4d level. © 1989 Chapman and Hall Ltd.