Optical Properties of Oxide Magnetic ZnO, Zn0.95Mn0.05O and Cu2O Nanopowders

ZnO, Zn0.95Mn0.05O and Cu2O nanocrystals are synthesized. Excitonic lines in absorption spectra of these materials are detected. In photoluminescence and photoluminescence excitation spectra of Zn0.95Mn0.05O the dangling bond hybrid (DBH) state is found. It has splitted out from the top of the valence band due to the hybridization between d-states of the Mn impurity and the p-states of oxygen. © 2009 Elsevier B.V. All rights reserved.The work was performed with the partial support of the Russian Foundation for Basic Research (Grants nos. 07-02-00910_a and 08-02-99080 r- ofi)

Clinical diagnostic criteria of efficiency for combined etiopathogenetic therapy in patients with chronic Epstein–Barr virus infection

Treatment of chronic viral infections accompanied by permanent virus persistence in the target epitopes of the oral cavity, skin, urogenital tract is complicated by virtual lack of available drugs exerting combined systemic virulicidal and immunomodulatory effects. Here we demonstrate clinical and immunological efficacy of combined therapy in treatment of Epstein–Barr virus (EBV)-associated chronic infections. The aim of the study was to evaluate the clinical and immunological efficacy of combined etiopathogenetic therapy using the Acegram cosmetic product in patients with EBV-associated chronic infections. Materials and methods. There were enrolled 40 patients monitored before treatment as well as 20 patients followed up after combination therapy (cycle therapy consisted of oral valaciclovir (Valtrex) applied at dose of 500 μg twice a day for 10 days, glucosaminylmuramyldipeptide (Licopid) — 10 mg 2 twice a day for 10 days, topical irrigation for mucous membranes with granulocyte-macrophage colony-stimulating factor active center-derived peptide (Acegram-spray) 3 times a day for 10 days. If necessary, treatment courses were repeated 20 days after the onset. All patients were examined for the presence of EBV genomes in the oral fluid and blood using the qualitative and quantitative polymerase chain reaction (PCR) using the DNA technology test system (Russia) on a DT-Lite device prior treatment and 30, 60 days post-therapy time points. In addition, serum samples were analyzed for level of class G immunoglobulins specific to the EBV nuclear and capsid antigens by using enzyme immunoassay (test systems manufactured by CJSC Vector Best, Russia) as well as immune status (clinical methods, enu flow cytometry evaluation of the phagocytic activity of neutrophils, ELISA method). Results. Use of single or two course combination therapy in subjects with fully eradicated EBV carriage associated with reversed clinical symptoms was accompanied by recovered immune system status (T and B cells, T-helper cells, CD3+ CD25+  cells, phagocytosis parameters). A non-invasive approach proposed for controlling virus elimination in the oral fluid by using polymerase chain reaction method may serve as to objectively monitor therapeutic efficacy

Cathodoluminescence of zinc oxide crystals grown from melt under high pressure in the presence of ytterbium oxide

International audienceA mixture of poly-and single crystals of zinc and ytterbium (2 at.%) oxides were grown from the melt at high temperature (1430 °C) and high pressure (3.8 GPa). The crystals were transparent under examination with naked eye. The diameter of crystals was in the range from 0.005 to 2 mm. X-ray diffraction confirmed the presence of individual zinc and ytterbium oxides in the recovered samples. No change in zinc oxide lattice parameters was observed compared to pristine zinc oxide. Cathodoluminescence spectra of the mixture were recorded at 77 and 293 K. The collected spectra exhibit UV, green and nearinfrared bands due to exciton recombination, presence of oxygen vacancies and ytterbium ions in ZnO crystals, respectively

Observation of 430 nm Electroluminescence from ZnO/GaN Heterojunction Light-Emitting Diodes

In this work, we report on the growth, fabrication, and device characterization of wide-band-gap heterojunction light-emitting diodes based on the n-ZnO/p-GaN material system. The layer structure is achieved by first growing a Mg-doped GaN film of thickness 1 μm on Al2O3(0001) by molecular-beam epitaxy, then by growing Ga-doped ZnO film of thickness 1 μm by chemical vapor deposition on the p-GaN layer. Room-temperature electroluminescence in the blue-violet region with peak wavelength 430 nm is observed from this structure under forward bias. Light–current characteristics of these light-emitting diodes are reported, and a superlinear behavior in the low current range with a slope 1.9 and a sublinear behavior with a slope 0.85 in the high current range are observed

Fabrication and Characterization of n-ZnO/p-AlGaN Heterojunction Light-Emitting Diodes on 6H-SiC Substrates

We report on the fabrication of n-ZnO/p-AlGaN heterojunction light-emitting diodes on 6H-SiC substrates. Hydride vapor phase epitaxy was used to grow p-type AlGaN, while chemical vapor deposition was used to produce the n-type ZnO layers. Diode-like, rectifying I-V characteristics, with threshold voltage ~3.2 V and low reverse leakage current ~10-7 A, are observed at room temperature. Intense ultraviolet emission with a peak wavelength near 389 nm is observed when the diode is forward biased; this emission is found to be stable at temperatures up to 500 K and shown to originate from recombination within the ZnO

Observation of 430 nm Electroluminescence from ZnO/GaN Heterojunction Light-Emitting Diodes

In this work, we report on the growth, fabrication, and device characterization of wide-band-gap heterojunction light-emitting diodes based on the n-ZnO/p-GaN material system. The layer structure is achieved by first growing a Mg-doped GaN film of thickness 1 μm on Al2O3(0001) by molecular-beam epitaxy, then by growing Ga-doped ZnO film of thickness 1 μm by chemical vapor deposition on the p-GaN layer. Room-temperature electroluminescence in the blue-violet region with peak wavelength 430 nm is observed from this structure under forward bias. Light–current characteristics of these light-emitting diodes are reported, and a superlinear behavior in the low current range with a slope 1.9 and a sublinear behavior with a slope 0.85 in the high current range are observed

ZnO-Based MIS Diodes Prepared by Ion Implantation

A ZnO-based metal-insulator-semiconductor (MIS) type diode, with low leakage and a threshold voltage of about 3 V, has been fabricated using an isolation layer achieved by N+ ion implantation. Ultraviolet light emission peaking at 388 nm and with full width of half maximum 0.12 eV has been observed under forward bias at room temperature. The properties of this emission have been studied as a function of injection current