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Quantum dots (QDs) are widely used for enhancing the performance of optical devices. Intermediate-band solar cells that use multistacked QDs can surpass the conversion efficiency of conventional silicon cells. We performed the optical characterization of In0.4Ga0.6As/GaAs multistacked QDs without strain compensation. We used the theoretical and experimental techniques prescribed for intermediate-band solar cells, i.e., photoluminescence (PL) spectroscopy and two-color excitations spectroscopy. The interdot spacings were not uniform and were found to be 15 nm and 7 nm. The results verify the formation of intermediate bands by the multistacked QDs. Using the theoretical studies and experimental results, we performed an in-depth study on the mechanism underlying the formation of intermediate bands by the multistacked QDs and the effect of different interdot spacings.

Objective The purpose of this study was to describe a newly developed dental panoramic system based on the tomosynthesis method and to validate the accuracy of linear and spatially oriented planar images. Study design An original robotic mechanism incorporating a new high-speed cadmium-telluride (CdTe) semiconductor detector was fabricated to acquire panoramic images (raw data). The shift-and-add tomosynthesis method was applied to facilitate changes in the depth of the panoramic imaging layer. Using the texture mapping method, planar and spatially oriented images were reconstructed along a custom curved imaging plane. Using a custom phantom and dry skulls, the accuracy of selected linear measurements was evaluated. Results Preliminary measurements demonstrated acceptable linear accuracy in reconstructed panoramic images with variations Conclusions This preliminary investigation demonstrates that dental panoramic images acquired by a novel robotic mechanism and CdTe detector using a tomosynthesis method provides planar and spatially oriented images with an image quality that may be acceptable for dental practice.

We report on the electronic properties and band structure of multistacked quantum dots (QDs) fabricated without a strain compensation technique. It is possible to realize a small interdot spacing and introduce a strong quantum mechanical coupling. From the using temperature dependence, polarized photoluminescent spectra, and photoluminescent excitation experiments, we observe a markedly different behavior depending on the interdot spacing. These results evidence that minibands of electrons and holes are formed with interdot spacings of 7 and 3.5 nm, respectively. In addition, thise results are in good agreement with numerical calculations. We describe in detail the miniband formation and electronic structure of multistacked QDs with various interdot spacings of 10 nm or less.

The sol-gel method was applied to create Al2O3-Cr2O3 ceramics using aluminum ethylacetoacetate diisopropylate and chromium (III) chloride hexahydrate as starting materials. In the calcination at 600-1200°C it was found that the grains of Cr2O3-rich solid solution grew when they were exposed to the surrounding Al2O3-rich amorphous particles. The composition of the powders obtained by the sol-gel process changed with calcining temperature. Cr2O3-rich solid solutions firstly crystallize at low temperature and the composition of the crystallites changes as the crystals grow and react with the surrounding Al2O3-rich phases. The final sintered bodies fired under an Ar atmosphere showed higher relative densities as compared with those fired in air. A dense sintered body was not obtained when abnormal grains grew when calcining occurred.