ANISOTROPIC LASER CRYSTALLIZATION OF A-SE

Anisotropic laser-stimulated crystallization is reported for amorphous selenium (Se) films due to irradiation by linearly polarized He-Ne or Ti:Sapphire (630-750 nm) laser beams with sample temperatures at and slightly above the glass transition temperature. Both beta-monoclinic and hexagonal crystalline phases are detected in the crystallized film by X-ray diffraction (XRD) measurements. The optical contrast between crystalline and amorphous parts of the film is larger when crystalliz ation is induced by linearly polarized light as compared to crystalliz ation by unpolarized light. The origin of anisotropic nuclei and their anisotropic growth is discussed and it is shown that the mechanisms o f optically and thermally induced crystallization are essentially diff erent. (C) 1998 Elsevier Science B.V. All rights reserved.