The spatial distributions of the cathodoluminescence (CL) emissions from thin ZnS films on GaAs(100) have been examined by the low-temperature CL measurement system combined with a transmission electron microscope (TEM). The correlation between these CL emissions and structural defects were studied by comparing the monochromatic CL images with the TEM images for both plan-view and cross-sectional observations. It is found that the neutral acceptor–bound exciton associated emission (A0,X) and the free-electron-to-ionized acceptor transition emission (e,A) are affected by the stacking fault distribution. The localization of the emission due to the deep-level emission transition near the interface suggest the diffusion of Ga atoms from the GaAs substrate. The characteristic distributions of the CL emission regions can be explained by considering the competitions among the recombination channels of those radiative processes for each type of an excess carrier, an electron, or a hole.

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To demonstrate light-path manipulation in arbitrary shapes we fabricated coupled-resonator optical waveguides (CROWs) having a 90 degrees-corner structure on a lithographically patterned substrate. The spectra of propagation light within the CROWs were directly measured by guide-collection-mode near-field scanning optical microscopy. The spectra revealed that the propagation light through the CROWs has a larger transverse-magnetic polarization mode than a transverse-electric (TE) one. The most plausible cause of the lower intensity in the TE mode is that light leaks out to the Si substrate.

We present a colloidal crystal wire composed of thousands of connected microspheres that is fabricated by a simple dewetting process utilizing a drain phenomenon, and we directly observe the light propagation within the wire by near-field scanning optical microscopy. The optical properties of propagation light suggest that the propagation mechanism was attributed mainly to nanojet-induced mode coupling for the straight propagation component and partly to whispering-gallery mode coupling within the colloidal crystal wire.