Chernyuk A. Non-equilibrium phase transformations in crystals induced by an external irradiation

The thesis deals with investigation of non-homogeneous structure of luminescence during intense laser irradiation of semiconductors with coupled quantum wells, and also investigation of photoinduced phase transformations in organic crystals. The circle, which is concentric to the laser spot, is broken down into fragments with reducing the rate of electron and hole recombination, and also with temperature decrease. In case of an aperture in metallic electrode, a structure of separate islands forms along the aperture. With pumping increasing or temperature growth, separate islands split into a solid circle. A model of photoinduced phase transition is composed for organic crystals with charge transfer complexes. The transition happens between neutral and ionic states of a molecule via relaxation from the excited level. A sharp growth of phototransformed molecules fraction happens after some time of irradiation. This time interval reduces with pumping growth.