STRUCTURAL AND MORPHOLOGICAL ANALYSIS OF REACTIVELY SPUTTERED TELLURIUM SUBOXIDE THIN-FILMS

Structural, morphological and optical analysis has been performed on tellurium suboxide thin films grown by rf reactive sputtering before and after a heat treatment (200-degrees-C for 5 min). Morphology and structure of the samples have been correlated with optical data, for films deposited both on glass and on quartz with the same conditions of deposition. Transmission electron microscopy analysis has shown that they are made of submicrometric Te and TeO2 grains from which both sharp and diffuse rings in the selected-area electron diffraction patterns are observed. A strong dependence of the morphology and of the structure on the substrate has been observed. On the other hand, the variation of transmissivity which is observed as a consequence of heat treatment does not depend on the substrate. It is correlated with the variation of the area fraction covered by the tellurium grains.