Ferromagnetism with T(c)>350 K is observed in the diluted magnetic semiconductor Ni(2+):ZnO synthesized from solution. Whereas colloidal Ni(2+):ZnO nanocrystals are paramagnetic, their aggregation gives rise to robust ferromagnetism. The appearance of ferromagnetism is attributed to the increase in domain volumes and the generation of lattice defects upon aggregation. The unusual temperature de...

Nanocrystal assemblies are being explored for a number of optoelectronic applications such as transparent conductors, photovoltaic solar cells, and electrochromic windows. Majority carrier transport is important for these applications, yet it remains relatively poorly understood in films comprised of touching nanocrystals. Specifically, the underlying structural parameters expected to determine...

co2+ & er3+ co-doped zno nanocrystals were synthesized by the hydrothermal method at 180°c and ph= 12 for 48 h. powder xrd patterns indicate that the zn1-2xerxcoxo crystals (0.00

ZnO and ZnO: Mn nanocrystals synthesized via reverse micelle method. The structural properties nanocrystals were investigated by XRD and Transmission electron microscopy (TEM). The XRD results indicate that the synthesized nanocrystals had a pure wurtzite (hexagonal phase) structure. The various optical properties of these nanocrystals such as optical band gap energy, refractive index, dielectr...

We review two strategies for growing ZnO nanowires from zinc salts in aqueous and organic solvents. Wire arrays with diameters in the nanoscale regime can be grown in an aqueous solution of zinc nitrate and hexamethylenetetramine. With the addition of poly(ethylenimine), the lengths of the wires have been increased to 25 mum with aspect ratios over 125. Additionally, these arrays were made vert...

Quantum dots (QDs) or semiconductor nanocrystals are of great interest to fundamental studies but have also potential applications as biological probes (Medintz et al., 2005), fluorescent biosensor (Costa-Fernandez et al., 2006), light-emitting diodes (LEDs) (Lim et al. 2007), and solar cells (Robel et al., 2006). Owing to the effect of quantum confinement, QDs show exceptional physical and che...

We present a comparative investigation of the morphological, structural, and optical properties of vertically aligned ZnO nanowires (NWs) before and after high energy argon ion (Ar(+)) milling. It is found that the outer regions of the as-grown sample change from crystalline to amorphous, and ZnO core-shell NWs with ZnO nanocrystals embedded are formed after Ar(+) milling. Optical properties of...

A facile, template-free method was used to grow large areas of well-aligned ZnO nanowire arrays on amorphous SiO2 substrates. The arrays are composed of vertically aligned, single-crystalline, wurtzitic [001] ZnO nanowires whose diameters were easily controlled by growth temperature, adjusted by changing the distance between the substrate and the precursor material in the growth chamber. A vapo...

Since the first report of ultraviolet lasing from ZnO nanowires, substantial effort has been devoted to the development of synthetic methodologies for one-dimensional ZnO nanostructures. Among the various techniques described in the literature, evaporation and condensation processes are favored for their simplicity and high-quality products, but these gas-phase approaches generally require econ...

One-dimensional (1D) coordination polymer, [Zn(4,4´-bpy)(H2O)4](ADC).4H2O (1) (4,4´-bpy = 4,4´-bipyridine and H2ADC = acetylenedicarboxylic acid), and three-dimensional (3D) metal-organic framework (MOF), Zn(ADC)2.(HTEA)2(2) (HTEA = triethylamine) were prepared at room temperature. The compounds were characterized by single-crystal X-ray diffraction and powder X-ray diffraction (PXRD) analyses....