We theoretically investigate exciton states of colloidal nearly spherical ZnO nanocrystals with diameters from 2 nm to 6 nm. The sizes of considered ZnO nanocrystals are chosen to be slightly larger than the exciton Bohr radius of bulk ZnO. A number of characteristic features of excitons are revealed in this intermediate quantum confinement regime. The exciton center of mass is found to be prol...

We report a facile chemical route for the synthesis of monodisperse nanocrystals of various metal sulfides (PbS, Cu(2)S, and Ag(2)S) and their assemblies into nanocrystal superlattices (NCSs); the sulfides NCSs were precipitated by adding ethanol to nanocrystal colloids, which were obtained directly by a reaction between metal thiolate and thioacetamide in a pure dodecanethiol solvent.

CdS nanocrystals were prepared in water-in-oil microemulsions. The nanocrystal properties, absorption and luminescence spectra and size distributions, were monitored at different times after mixing the microemulsions of the two precursors to obtain information on their growth mechanism. In particular, CdS nanocrystals were prepared using water-in-heptane or water-in-nonane microemulsions. The r...

This paper describes the fabrication, and structural and electrical characterization of a new, aerosolnanocrystal floating-gate FET, aimed at non-volatile memory (NVM) applications. This aerosolnanocrystal NVM device features prograderase characteristics comparable to conventional stacked gate NVM devices, excellent endurance (>lo5 P/E cycles), and long-term non-volatility in spite of a thin bo...

The nanocrystal 3C-SiC/ZrO₂ bilayer films that could be used as the protective coatings of zirconium alloy fuel cladding were prepared on a single-crystal Si substrate. The corresponding nanocrystal 3C-SiC film and nanocrystal ZrO₂ film were also dividedly synthesized. The microstructure of nanocrystal films was analyzed by grazing incidence X-ray diffraction (GIXRD) and cross-sectional transmi...

The ability to engineer the optical properties of the semiconductor nanocrystals by controlling their growth size, shape, materials, coatings, etc makes them appealing for many optical applications. Despite the impressive development of nanocrystal manufacturing capabilities, there are still many basic questions about how to model nanocrystals that have yet to be adequately answered. This thesi...

Elucidating the fundamental mechanisms of nanocrystal growth necessitates the utilization of high spatial resolution imaging techniques that are capable of directly imaging individual nucleation and growth events within a liquid phase. By combining time-resolved imaging datasets with quantitative image analysis algorithms, the factors controlling chemical transformations can be determined by an...

A quantitative understanding of nanocrystal phase transformations would enable more efficient energy conversion and catalysis, but has been hindered by difficulties in directly monitoring well-characterized nanoscale systems in reactive environments. We present a new in situ luminescence-based probe enabling direct quantification of nanocrystal phase transformations, applied here to the hydridi...

CoO nanocrystal/graphene nanosheets (GNS) composites, consisting of a triangular CoO nanocrystal of 2~20 nm on the surface of GNS, are synthesized by a mild synthetic method. First, cobalt acetate tetrahydrate is recrystallized in the alcohol solution at a low temperature. Then, graphene oxide mixed with cobalt-precursor followed by high vacuum annealing to form the CoO nanocrystal/GNS composit...

The photochemical instability of CdSe nanocrystals coated by hydrophilic thiols was studied nondestructively and systematically in water. The results revealed that the photochemical instability of the nanocrystals actually included three distinguishable processes, namely the photocatalytic oxidation of the thiol ligands on the surface of nanocrystals, the photooxidation of the nanocrystals, and...