Physico-chemical properties of the thin films of the SbxSe100 − x system (x = 90, 85, 80).

The bulk samples of Sb x Se 100 − x system (x = 90, 85, 80) and their amorphous thin films were prepared by flash evaporation method. The films possess good thermal stability and high values of the activation energy of crystallization. The activation energy of crystallization (E a ) of the thin films Sb 85 Se 15 and Sb 80 Se 20 was found to be 2.97 and 2.55 eV, respectively. The E a of Sb 90 Se 10 was found to be 1.79 eV for first step and 2.95 eV for second step. The homogeneous thin amorphous films were crystallized by nanosecond laser pulses, by annealing at 235 and 360 °C and during the measurement of temperature dependence of electrical resistivity. The crystalline phase possesses much lower electrical resistivity than the amorphous one (ΔR s ≈ 10 3 ); the temperature of crystallization T c is from the region of 150–161 °C. The structure of prepared films as determined by X-ray diffraction analysis revealed that the films crystallized by laser pulses and by annealing at 235 °C contain only one phase of Sb-like structure. The films of composition Sb 80 Se 20 and Sb 85 Se 15 annealed at 360 °C contain two phases of Sb and Sb 2 Se 3 . The film of composition Sb 90 Se 10 annealed at 360 °C contains one phase of Sb-like structure. The optical reflectivity change due to crystallization is also large (ΔR opt. ≈ 20–30%). The refractive index n of crystalline samples is higher than that of amorphous films (Δ n ≈ 1.5–3.1 for transparent part of spectrum); it is higher for films with higher Sb content. The real and imaginary parts of permittivity, evaluated from ellipsometric measurement, are also much higher for crystalline state (up to 55) than for the amorphous one (< 33). The amorphous films are semiconductive, and their E g opt. (0.28–0.35 eV) is decreasing with an increasing content of Sb. In spectral region of λ = 360–830 nm, the real part of permittivity of crystalline phase is negative and the imaginary part of permittivity is not high, especially for the Sb 90 Se 10 samples. Such films are perspective not only as the phase change materials, but also as the plasmonic materials. [ABSTRACT FROM AUTHOR]