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

Vanadium oxide as well as molybdenum oxide thin films have been found to sh ow electrochromism and metal insulator transitions. Incorporation of vanadi um ion into molybdenum oxide lattice not only changes the lattice parameter s but also shows prominent spectral changes in X-ray emission spectra. Kbet a 1-3 emission spectra of vanadium in different alloy films of V2O5MoO3 sys tem have been studied here and these have been compared with the X-ray emis sion spectra of similar composition of V2O5MoO3 powders. For Kbeta 1-3 emis sion, the difference in values of asymmetry indices of thin films and powde rs is marginal, although considerable tailing towards high energy is observ ed in thin films. By curve fitting procedure, the Kbeta 1-3 emission spectr a have been resolved to several gaussian peaks, and these have been explain ed on the basis of vacancy-induced electronic states, crossover transitions advocated in molecular orbital theory and plasmon oscillation.