LASER RECORDING IN TELLURIUM SUBOXIDE THIN-FILMS

Tellurium suboxide (TeO//x) films prepared by coevaporation consist of tiny grains of tellurium embedded in a TeO//2 matrix. The size of the tellurium grains depends on the preparation conditions. Except for samples with exceedingly small grains, crystalline diffraction patterns can be observed by using selected-area electron diffraction even though these samples show amorphous x-ray diffraction patterns. Heat treatment causes a transition in optical properties and the appearance of peaks for crystalline tellurium in x-ray diffraction. Thermal writing with a focused diode laser on both heat-treated and as-deposited samples gave recorded marks with high sensitivity and good contrast, although an incubation period of many seconds is required for the full development of the marks. The observed laser recording behavior cannot be explained by a simple amorphous-to-crystalline transition, and a new writing mechanism is proposed.