THERMALLY-INDUCED CHANGES IN TEOX THIN-LAYERS

TeO(x) layers with controlled Te/0 ratio and thickness are prepared by thermal coevaporation of TeO2 and Te. Using various transmission and scanning electron microscopy techniques it is shown that the as-deposi ted layers represent a composite system, consisting of finely disperse d, partly agglomerated crystalline Te particles embedded in an amorpho us TeO2 matrix with columnar structure and fine-grained substructure. The effect of annealing and laser exposure on the layers is investigat ed. A strong correlation of the change in transmission and the Te redi stribution is found. It is shown that the variations in the optical pr operties of the TeOx layers are caused by aggregation of the crystalli ne Te particles and migration of Te to the upper free surface of the l ayer.