Evaluation of first crystallization in amorphous Ag-added Ag5.5In6.5Sb59Te29 thin films

In this article, several experimental results were reported for the evaluation of the first crystallization speed (v(1st)) on the nanosecond time scale as well as the material characteristics of the Ag-added Ag-In-Sb-Te films. The (Ag)(x)(Ag5.5In6.5Sb59Te29)(1-x) (x=0, 0.1, and 0.2) films were prepared by thermal evaporation and their phase transformation from an amorphous state to a hexagonal structure via a stable fcc structure was confirmed using x-ray diffraction. Some differences were measured in the optical transmittance (T-OP) and absorption between the amorphous and crystalline films in the wavelength (lambda) range of 800-3000 nm using an UV-visible-IR spectrophotometer. The v(1st) values, evaluated using nanopulse reflection response, slightly improved with an increase in the Ag content. For example, the nucleation time/average growth time ratio for the Ag5.5In6.5Sb59Te29 and Ag-0.2(Ag5.5In6.5Sb59Te29)(0.8) films were approximately 170 ns/70 ns and 110 ns/60 ns, respectively, for an illumination power of 7 mW.