Search

Equivalent models using scatter function and the statistical analysis with Hypothesis-test are provided to overcome the computational requirement for simulating complicated microstructures of photoelectronic devices. Strategies are introduced to explore the minimal number of rays and spectrum resolution to complete the analysis. Results indicate that on an average 1/25 reduction factor of computational time is possible, which is extremely helpful if an optimization procedure is required for microstructures.

In this study, the Mg doping effects on the nanostructural dependence of photoluminescence and the photosensing properties in Zn1−xMgxO (x = 0.01, 0.03, and 0.05) nanorod arrays were systematically examined. The vertical-aligned nanorod arrays were separately grown on ZnO-seeded n-Si substrates via a low-temperature hydrothermal process. X-ray diffraction analysis revealed that all Zn1−xMgxO nanorod arrays exhibited the same preferentially c-oriented wurtzite structure. Images of all the Zn1−xMgxO nanorod arrays provided by field emission scanning electron microscope showed that both the length and diameter of the Zn1−xMgxO nanorod arrays increased with increasing Mg doping concentration. Also, an enhanced blue-shifted ultraviolet (UV) emission and a reduced visible emission were observed from the photoluminescence spectra of the Zn1−xMgxO nanorod arrays. The former indicated the decrease of defects and the latter indicated the enhancement of the crystallinity and the increase in optical bandgap. Current–voltage curves were separately measured in the dark and under UV illumination. Finally, the mechanism of the Mg doping effects on the corresponding defects, bandgap, and UV photosensing characteristics of the Zn1−xMgxO nanorod arrays was investigated in detail.

Many reports and patents address tracking-type systems to complete and optimized the acquisition of solar energy. However, fixed-type systems contribute the most of the market to the solar photovoltaic system (SPVS) for the existing buildings. Based on this fact, it is important to discuss and understand the feasible setup parameters to achieve the optimum radiation-collection-efficiency of a fixed-type system. The purpose of the present report is to provide the methodology and to investigate the optimum angles of the system facilities through minimum mathematics. The calculations show that for the demonstrated locations, the maximum efficiency for the whole year of a fixed-type system can reach more than 61% efficiency, compared to a total tracking system at the same location and time intervals. Based on these calculations, the appropriate optical system can be designed to improve system performance for the majority buildings requirements in any location.

Modelling of thermal deformation and the corresponding stress distribution are significant for the thin-film design. In order to evaluate the mechanical properties experienced by a thin film parameter on the rigid substrate, the author proposes a semi-analytical model to estimate the deformation of the thin film under various conditions. The physical interpretation and simplification of each term is obtained through the order-of-magnitude analysis. Analytical forms for the thin film deformation can be obtained, and the stress in the film can be easily determined using the proposed model through the constitutive law.

Stresses distribution between the interfaces of the materials is critical for structures like thin film layers, organic/inorganic light emitting diode layers and various kinds of modern optical-electronics components with stacking materials properties. The classical Aleck's model ( 1949 ) can be considered as a very simple and a practical method to analyze these kinds of structures. In order to deal with it, the integration scheme is used to solve the displacement equations with zero displacements on the clamped edge including the clamped corner. The condition of zero traction is imposed at all of the grid points on the free surface except for the clamped corner of layers. The results show a stress singularity at the clamped corner. This agrees with an existing finite element solution performed on a very fine grid. By contrast, the known Kantorovich solution for Aleck problem from Blech and Kantor (1984) did not predict such stress singularity. As remarked by Blech and Kantor, the Kantorovich solution posed difficulties in convergence in the immediate vicinity of the clamped corner, thus is questionable to apply the results for the layer structures through this model.