Optical properties of nanostructures in layered metal tri-iodide crystals

2019-10-10 12:54:05

crystal optical size nanostructures exciton

责任者: Komatsu, T.;Karasawa, T.;Akai, I.;Iida, T. 单位: Dept. of Phys., Osaka City Univ., Japan 来源出处: Journal of Luminescence(J. Lumin. (Netherlands)),1996/10/,70(1-6):448-67 摘要: The optical response of excitons confined in characteristic nanostructures in layered metal tri-iodide crystals introduced by some irregular stackings from the bulk structures is reviewed. In BiI3 a specific stacking fault takes place during crystal growth constructing macroscopic planar defects. In this space conspicuous localized exciton transitions occur below the intrinsic absorption edge. Another stacking disorder introduced by applying external stress in this crystal brings about a new nanostructure domain of symmetry D3d different from that of bulk symmetry C3i2. The optical transitions due to new structures appear in the lower energy region as an absorption and luminescence line series. Similar nanostructures are induced in SbI3 crystals under hydrostatic pressure. In these nanostructures, the electronic structure is analyzed by a model based on the confined excitons in a nanoscale disk-like shape space. The magnetic field effect confirms the structure in the wave function-size scale. The nanoscale disk-like structure of BiI3 in CdI2 matrices is also obtained by a hot wall technique and mixed crystal annealing, which is realized by observing the size distribution with an electron microscope. In a BiI3 disk in CdI2 Stokes shifted photoluminescence bands appear. The Stokes shifts of the luminescence bands are understood by considering the size-dependent exciton-phonon interaction. In these nanostructures large optical nonlinearity under the intense laser field was obtained 关键词: antimony compounds;bismuth compounds;crystal field interactions;grain size;localised states;magneto-optical effects;nanostructured materials;optical saturation;phonon-exciton interactions;photoluminescence;piezo-optical effects;quantum confined Stark effect;stacking faults;transmission electron microscopy;visible spectra;semimetal triiodides;layered crystals;nanostructures;exciton optical response;stacking faults confinement;macroscopic planar defects;localized exciton transitions;nanostructure domain symmetry;light absorption;luminescence line series;hydrostatic pressure effects;disklike space confinement;magnetic field effects;hot wall preparation technique;mixed crystal annealing;grain size distribution;electron microscopy;photoluminescence spectral shift;Stokes shift;exciton phonon interaction;optical nonlinearity;crystallite size effect;growth faults;deformation faults;energy level diagram;cleaving effects;mesoscopic systems;Cd diiodide matrices;optical Stark effect;saturation spectra;1.8 to 3 eV;SbI3;BiI3;CdI2