This study has investigated the effect of dopant concentration on the luminescent emission of Er in ZrO2 nanocrystals. The structure and morphology of the resulting nanocrystals were characterized by X-ray diffraction and field emission scanning electron microscope. The room-temperature optical properties of synthesized nanocrystals were studied by photoluminescence spectroscopy. The dependence...

We have studied the surfaces of zirconia (ZrO2) by first-principles calculations using density functional theory. We predict surface energies and relaxations for the principal surfaces of different bulk phases of zirconia. We find that the stoichiometric tetragonal~111! and monoclinic~1̄11! are the most stable surfaces. We find a strong linear correlation between surface energies before and afte...

GaN-based metal-oxide-semiconductor capacitors with ZrO2 as the dielectric layer have been prepared by atomic layer deposition. The accumulation and depletion regions can be clearly distinguished when the voltage was swept from -4 to 4 V. Post-annealing results suggested that the capacitance in accumulation region went up gradually as the annealing temperature increased from 300 to 500 °C. A mi...

During thermal oxidation of binary amorphous AlxZr1-x solid solutions over wide alloycomposition (0.26 ≤ x ≤ 0.68) and oxidation-temperature (350 °C – 560 °C) ranges, a single amorphous ternary oxide phase of well-defined stoichiometry, (Al0.33Zr0.67)O1.83, emerges. The composition of this unexpectedly stoichiometric ternary amorphous oxide phase, that develops instead of the crystalline oxide ...

Objective: Today, special attention is paid to the use of zirconium dioxide nanoparticle (nano-ZrO2), a neutral bioceramic metal, particularly for drug and gene delivery in medicine. However, there are some reports implying that use of nano-ZrO2 is associated with cytotoxic effects like inhibiting the cell proliferation, DNA damage and apoptosis. In the present study, we examined whether nano-Z...

We first review earlier work in which we computed the first-principles structural, vibrational, and lattice dielectric properties of the cubic, tetragonal, and monoclinic phases of ZrO2 and HfO2. We then discuss two approaches to the construction of realistic models of amorphous ZrO2: a bmelt-and-quenchQ ab-initio molecular dynamics approach, and an bactivation–relaxation techniqueQ. The struct...

We have observed electron and hole trapping phenomena in thin films of ZrO2 obtained by plasma assisted deposition. Limited thickness dependent measurements suggest that the holes are trapped uniformly through the film while the electrons trap at the ZrO2 /Si interface. Relaxation of the trapped holes occurs rapidly after removal of negative stress ~;90% in 15 min!, while electron relaxation po...

The effects of calcium fluoride (CaF2) additions on the densification and mechanical properties of hydroxyapatite–zirconia composites (HA–ZrO2) were investigated. When small amount of CaF2 was added, the density of the composites was markedly enhanced. The reactions of HA with CaF2, which led to the formation of fluorapatite (FA), were attributed to the observed improvements in densification. W...

We describe a model which can be used for in vitro biocompatibility assays of biomaterials. We studied the in vitro response of human osteoarthritis or rheumatoid arthritis fibroblast-like synoviocytes to Al2O3 or ZrO2 particles by analysing the production of interleukin-1 (IL-1) and interleukin-6 (IL-6) and the metabolism of arachidonic acid via lipoxygenase and cyclo-oxygenase pathways. Our r...