Le Journal de Physique IV 03 (1993) C5-433-C5-436
Nonlinear optical spectra of confined and localized excitons in mesoscopic domain and quasi-2D stacking fault interface in BiI3 crystalsI. AKAI, H. KONDO, M. ICHIDA, T. KARASAWA and T. KOMATSU
Department of Physics, Faculty of Science, Osaka City University, 3-3-138 Sugimoto Sumiyoshi-ku Osaka 558, Japan
Saturation spectra of the excitons confined and localized at several kinds of stacking disorders in layered crystal BiI3 are studied. The quasi-two dimensional exciton localized at the stacking fault interface does not saturate its absorption strength below the density of 105W/cm2 due to the large binding energy and the lateral center-of-mass motion along the interface. On the exciton system associated with some polytypic structures contained in a very small region, an obvious absorption saturation is observed. The behaviour of absorption saturation is well described by a saturation effect on a simplified two-level system having a homogeneous line broadening. An absorption saturation is also observed on the confined excitons in mesoscopic domains induced by the external deformation of the crystal. The pumping-laser photon-energy dependence of the saturation density characterizes this exciton system to be inhomogeneous.
© EDP Sciences 1993