Polycrystalline samples of titanium oxide were prepared by thermal sintering, in argon and air atmospheres at temperatures ranging from 1100 to 1500 • C, from powders of anatase and rutile phases. The samples sintered in argon were further treated in oxygen at the temperature of 800 • C for intervals of time up to 8 h. The luminescence emission of the initial powders was situated in the green region, with the peak at 580 nm. The sintering treatment in argon leads to a decrease of the luminescence intensity that appears as a broad band peaked at 550 nm in the case of anatase and as a band peaked at 450 nm in the case of the rutile phase. The sintering treatment in air causes the quenching of the emission in the visible region. In both cases, a sharp and intense emission appears in the infrared region at 800 nm for rutile and 820 nm for the anatase phase.The blue emission is sensitive to the treatment in oxygen atmosphere which causes mainly an intensity increase of the band at 450 nm. The treatment in oxygen results in the reconstruction of the polycrystalline sample surface as hexagonal shape protrusions and large terraces.

Visible luminescence from erbium oxide layers grown on crystalline and amorphous silicon (c-Si and a-Si) has been investigated. The results show strong red and green cathodoluminescence bands due to intraionic Er 3+ radiative transitions at room temperature. The use of c-Si or a-Si as substrate led to a red or green dominant emission, respectively, which has been explained in terms of the oxygen content in the substrate. The results obtained from samples grown in different atmospheres also support this assumption.

Correlations between the morphology and emission properties of trench defects in InGaN/GaN quantum wells J. Appl. Phys. 113, 073505 (2013) Depth-resolved cathodoluminescence spectroscopy of silicon supersaturated with sulfur Appl. Phys. Lett. 102, 031909 (2013) Whispering gallery and Fabry-Pérot modes enhanced luminescence from individual ZnO micro mushroom J. Appl. Phys. 113, 034313 (2013) Morphological, structural, and emission characterization of trench defects in InGaN/GaN quantum well structures Appl. Phys. Lett. 101, 212107 (2012) Local lifetime and luminescence efficiency for the near-band-edge emission of freestanding GaN substrates determined using spatio-time-resolved cathodoluminescence

Luminescence emission of nanocrystalline silicon films has been studied by cathodoluminescence (CL) in the scanning electron microscope. As-deposited films show a dominant band at 400 nm as well as a band centered at about 650 nm. CL spectra of porous silicon samples also show emission at 400 nm. Spectral changes induced by annealing and implantation treatments of the films suggest that the presence of nanocrystals is the origin of the observed CL.

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