Laser-induced crystallization of monoclinic nanowires in glassy selenium films

The authors investigate influence of 632.8 nm laser irradiation on structural properties of thin glassy (amorphous) Se films synthesized on quartz substrates using vacuum thermal evaporation. They first propose the fact that low power laser irradiation of Se films (power density P-S=80 W cm(-2)) initiates phase transformations, accompanied by growth of monocrystalline nanowires of metastable phase of monoclinic beta-Se-8 in the amorphous matrix at room temperature. New structural properties of Se films are proven to be long term stable at room temperature. It is shown that laser irradiation at P-S >= 800 W cm(-2) induces synthesis of a mixture of nanocrystallites of trigonal Se and monoclinic alpha-Se-8 in the amorphous films and their mass crystallization with growth of spherulites at room temperature.