Effect of metal substitution in ZrS3 and TiS3 compounds

The effects of metal substitution on the electronic and vibrational properties of ZrS3 and TiS3 are studied through UV-visible absorption, Raman and resonance Raman scattering experiments on various Zr1-xTixS3 ternary phases, 0 < x < 1. All these broad band semiconductors display excitonic type transitions on their absorption edge whose maxima vary monotonously from 500.0 to 960.0 nm as the titanium content increases. These excitons consist of d-like conduction electrons and the existence of higher-energy transitions due to 3p*(S-S) orbitals is confirmed by resonance Raman results in Zr0.6Ti0.4S3. The polarized Raman spectra of the solid solutions present variations in band-wave numbers as a function of the compositional parameter x and three different types of mode-behavior are observed depending on the nature of the vibrations. All the Raman results are sustained on force field calculations in ZrS3 and TiS3 and on the estimations of short-, medium-, and long-range interactions within each vibrational state. (author)