Vacancy-induced electronic states in substoichiometric V(2-x)Mo(x)0(3 +/-gamma) thin films and powders - A soft X-ray emission study

Abstract

Vanadium oxide as well as molybdenum oxide thin films have been found to show electrochromism and metal insulator transitions. Incorporation of vanadium ion into molybdenum oxide lattice not only changes the lattice parameters but also shows prominent spectral changes in X-ray emission spectra. Kbeta 1-3 emission spectra of vanadium in different alloy films of V2O5MoO3 system have been studied here and these have been compared with the X-ray emission spectra of similar composition of V2O5MoO3 powders. For Kbeta 1-3 emission, the difference in values of asymmetry indices of thin films and powders is marginal, although considerable tailing towards high energy is observed in thin films. By curve fitting procedure, the Kbeta 1-3 emission spectra have been resolved to several gaussian peaks, and these have been explained on the basis of vacancy-induced electronic states, crossover transitions advocated in molecular orbital theory and plasmon oscillation.