Modification of the optical reflectance spectra of epitaxial gallium arsenide by weak magnetic fields J. Appl. Phys. 112, 073513 (2012) Theoretical and experimental study of the optical absorption at longitudinal phonon or phonon-plasmon coupling mode energy: An example of GaN J. Appl. Phys. 112, 063531 (2012) Negative differential resistance associated with hot phonons J. Appl. Phys. 112, 063707 (2012) Photoluminescence properties and high resolution x-ray diffraction investigation of BInGaAs/GaAs grown by the metalorganic vapour phase epitaxy method J. Appl. Phys. 112, 063109 (2012) Optical properties of InGaPN epilayer with low nitrogen content grown by molecular beam epitaxyIn this work we study the influence of the thiourea/CdCl 2 concentration ratio used for the chemical bath deposition of CdS thin films on glass substrates, upon the CdS/CdTe interface recombination velocity in CdTe/CdS/glass structures, where the CdTe layer was grown on the CdS thin film by close space vapor deposition ͑CSVT͒-hot wall technique. The interface recombination velocity was measured by means of the photoacoustic ͑PA͒ technique in a heat transmission configuration, in which minority carriers are photoexcited at the CdTe layer after illumination through the substrate and the CdS thin film. For data processing, a theoretical model was developed for the generation of the PA signal. We show a reduction in the value of the recombination velocity respecting those obtained for samples where CdS was grown by CSVT, and we observe that a minimal value appears for a thiourea/CdCl 2 ratio in the CdS deposition solution equal to 5. These results show a good correlation with those of electrical measurements performed in solar cell devices.

The wingbeat of an insect relates directly to energy consumption, is a strong indicator of its rate of metabolism and physical structure, and inversely relates to the length of its wing and to the mass of its body. It is also a principal component in understanding the aerodynamic properties of its flight. In this paper, we introduce a method based on the use of high-speed cameras and computer vision techniques to analyze a bumblebee (Bombus impatiens) wingbeat. We start capturing images with a virtual stereo system when a bumblebee crosses two intersecting laser beams. Then, we detect moving objects using background subtraction. Next, via Fourier analysis of the observed optical flow contraction/expansion, and marginalization of prior knowledge, we estimate the wingbeat frequency. Finally, the information from the two virtual cameras is fused using a robust state estimation. Our system is well prepared to handle occlusions; it works with untethered insects; and it does not require the synchronization of a multi-camera system.

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Porous silicon layers were embedded with ZnTe using the isothermal close space sublimation technique. The presence of ZnTe was demonstrated using cross-sectional energy dispersive spectroscopy maps. ZnTe embedded samples present intense room temperature photoluminescence along the whole visible range. We ascribe this PL to ZnTe nanocrystals of different sizes grown on the internal pore surface. Such crystals, with different orientations and sizes, were observed in transmission electron microscopy images, while transmission electron diffraction images of the same regions reveal ZnTe characteristic patterns. V