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Na-containing surface compounds is likely to form during the formation of CZTS absorber. Still, the understanding of any potential influence on buffer layer growth and device performance is limited. In this work, we observed that NaxS compound can possibly form on the CZTS surface after annealing, and negatively affect the growth of the subsequent CdS buffer. The Na x S compound is oxidized to Na 2 SO 4 via air exposing the annealed CZTS surface, which allows greatly improved quality of the CdS layer. This provides new insights for improving the CdS/CZTS interface during the fabrication of CZTS solar cells.

Image segmentation is a key step in the process of realizing automatic diagnosis of the drosophila’s pathologic compound eyes. This article uses the chromatic aberration variable Cr ,extracted from the color images of drosophila’s compound eyes, to establish a two-dimensional histogram, with which and according to the principle of OTSU thresholding segmentation, image segmentation of the drosophila’s compound eyes has been realized. Based on massive computing of the two-dimensional OTSU thresholding, the Adaptive Genetic Algorithm (AGA), including robustness and parallelity, is then used to search for the best non-linear vector of two-dimensional threshold. A number of experiments are made and the application result proves that the two-dimensional OTSU thresholding method proposed in this paper takes a good effect.

We investigate the feasibility of the design of a small artificial compound eye that comprises micro-optical, micro-mechanical components and additional electronics for visual processing. The hybrid integration of this "mini-sensor" addresses important issues such as mechanic scale-effect, assembly of small parts and functional testing. The use of retinal scanning for the perception of visual motion is highlighted in the design of a small-sized horizontal array with a scanning retina of 2/spl times/30 photoreceptor elements (R/sub eye/=30 mm). The scanning motion is achieved by actuating the photodiode arrays with a piezoelectric bimorph cantilever beam coupled to a plate spring. The mini-compound eye, equipped with analogue motion detecting circuits, is able to guide the steps of a small mobile platform and perform multi-task visual processing for obstacle avoidance, tracking and pursuit of visual target.

This study presents comparative results of the design, fabrication and preliminary performance of two biomorphic visual sensors that are endowed with a scanning retina. The design of the visual sensors is inspired by the structure of the fly's compound eye that possesses a unique muscle+tendon actuation system for its scanning retina. We address the fabrication issues of visual sensors through the construction of a large scale prototype at the millimeter-scale whose performance is then compared to the one of a MEMS-fabricated prototype at the micro-scale. The motivation for the design of a small sized artificial visual sensor springs from the need to create more reliable, efficient and integrated smart visual sensors for robotic applications in particular for the autonomous visually-guided navigation of mobile robots.

High-performance Cu(In,Ga)Se/sub 2/ (CIGS) based solar cells are fabricated within a narrow range of processing options. In this contribution, alternative substrate, absorber, and buffer layer processing is considered. Cell performance varies considerably when alternative substrates are employed. These variations are narrowed with the addition of Na via a Na/sub 2/S compound. Sputtered and electrodeposited CIGS precursors and completed absorbers show promise as alternatives to evaporation. A recrystallization process is required to improve their quality. (In,Ga)/sub y/Se buffer layers contribute to cell performance above 10%. Further improvements in these alternatives will lead to combined cell performance greater than 10% in the near term.