Length versus radius relationship for ZnO nanowires grown via vapour phase transport

We model the growth of ZnO nanowires via vapour phase transport and examine the relationship predicted between the nanowire length and radius. The model predicts that the lengths of the nanowires increase with decreasing nanowire radii. This prediction is in very good agreement with experimental data from a variety of nanowire samples, including samples showing a broad range of nanowire radii and samples grown using a lithographic technique to constrain the nanowire radius. The close agreement of the model and the experimental data strongly support supporting the inclusion of a surface diffusion term in the model for the incorporation of species into a growing nanowire

Radiative recombination in GaN nanocrystals at high intensities of optical excitation

International audienceThe spectra of spontaneous UV luminescence of GaN nanocrystals excited by optical pumping at power densities ranging from 50 W/cm(2) to 50 MW/cm(2) are studied. At room temperature, radiation peaks related to the emission of free excitons and recombination of electron-hole plasma are revealed. The spectral characteristics of the emission of the electron-hole plasma in GaN is studied in the wide temperature range of 77-550 K. (c) 2005 Pleiades Publishing, Inc

Adaptive 3D unstructured mesh refinement

Algorithms for generating three-dimensional detailed computational meshes are considered. The algorithms are based on adaptive refinement of the original coarse meshes describing a 3D object. The purpose of adaptation is to form an accurate description of the volume and surface of a three-dimensional object for supercomputer modeling. Refinement of the boundary description is performed by projecting the cut elements of the coarse mesh onto the corresponding elements of the object’s surface