Synthesis and Optical Properties of B-Mg co-Doped ZnO Nanoparticles

Doping impurity into ZnO is an effective and powerful technique to tailor structures and enhance its optical properties. In this work, Zn1−xMgxO and Zn1−x−yMgxByO nanoparticles (x = 0, 0.1, 0.2, 0.3, 0.4; y = 0, 0.02, 0.04) were synthesized via one-pot method. It shows that the Mg and B dopants has great influence on crystallinity and surface morphology of ZnO nanoparticles, without changing the wurtzite structure of ZnO. The band structure study indicates that the competition of Conductive Band (CB) shift, Burstein–Moss (B-M) shift and Shrinkage effect will cause the band gap energy change in ZnO.

Giant Thermoelectric Figure of Merit in Fluorine Doped Single Walled Carbon Nanotube

Herein, we report on a giant thermoelectric figure of merit of a non-degenerate fluorine-doped single-walled carbon nanotube (FSWCNT) using a tractable analytical approach and the phonon lattice Boltzmann model (LBM). We investigate the influence of the doping concentration, and the overlapping integrals on the ZT. The ZT and the temperature range of operation can be tuned using the doping (impurity) concentration and the overlapping integrals, respectively. The lattice thermal conductivity obtained using the phonon LBM was calculated to be 107.2 W/mK which yielded a ZT greater than 20. Interestingly, the ZT obtained is higher than what has been reported in superlattices, (ZT~1.4) and superlattice nanowire, (ZT~ 4) at 300 K, making FSWCNT a potential candidate for thermoelectric applications.

SORPTION AND PHOTOCATALYTIC ACTIVITY ZNCUO (X=0,05 AND 0,15) TO AS (III) IN AN ALKALINE MEDIUM

С использованием формиатогликолятных комплексов ZnCu(HCOO)(OCHCHO) (0 ≤ х ≤ 0,15) получены твердые растворы ZnCuO с 1D и композиты ZnCuO / CuO со сферической морфологией агрегатов соответственно. Материалы апробированы в реакции фотоокисления As(III) при воздействии ультрафиолетового и видимого излучения. Установлено, что медь является эффективной допирующей примесью в составе твердого раствора ZnCuO (0 ≤ х ≤ 0,1). Присутствие ее в оболочке композита ZnCuO / CuO негативно влияет на фотоактивность материала вплоть до подавления фотокатализа в видимом световом диапазоне. Показана также сорбционная эффективность материалов к мышьяку независимо от состава и морфологии материала. Согласно данным рентгеновской фотоэлектронной спектроскопии на поверхности образцов после сорбции мышьяк находится преимущественно в виде As(III) . 1D solid solutions ZnCuO and composites ZnCuO / CuO with spherical morphology of aggregates from formate glycolate complexes ZnCuO (HCOO)(OCHCHO) (0 ≤ x ≤ 0,15) were obtained. All materials have been tested in the reaction of As(III) photooxidation upon exposure to ultraviolet and visible radiation. It was found that copper is an effective doping impurity in the composition of the solid solution ZnCuO (0 ≤ x ≤ 0,1). Its presence in the shell of the ZnCuO / CuO composite negatively affects the photoactivity of the material up to suppression of photocatalysis in the visible light range. The sorption efficiency of materials for arsenic is also shown, regardless of the composition and morphology of the material. According to x-ray photoelectron spectroscopy data, the surface of the samples after sorption contains arsenic mainly in the form of As(III).

Influence of oxygen vacancies on magnetic and transport properties of thin Zn1-xCoxOy films

The features of the structural, transport and magnetic properties of thin Zn1-xCoxOy films (x=0-0.45), fabricated on С-sapphire substrates by the pulsed laser deposition method are studied. It is found that the transport and ferromagnetic properties of the wurtzite Zn1-xCoxOy films nonmonotonously depend on Co concentration at room temperature. For the Zn0.87Co0.13Oy film, the strongest ferromagnetic signal is observed that is caused by formation of the greatest number of metallic Co clusters. A further increase of doping impurity concentration in the films leads to the oxidation of metallic Co and formation of the paramagnetic Co3O4 phase, in consequence of which the ferromagnetic signal subsides.

Physical Aspects of the Liquid Zones Thermomigration Method for Formation of Electronic Technics Materials with the Required Substructure

The paper analyzes the features of a liquid zones thermomigration process in a crystal for the formation of semiconductor materials with the required substructure, carried out in comparison with a diffusion method. The primary factors defining and accompanying the thermomigration process of liquid inclusion in a crystal are considered. The geometrical, concentration, temperature-time and other conditions at which the choice of the thermomigration effect as a local doping method is preferable are revealed and described. It is shown, that the thermomigration method possesses considerable advantages, in particular, the possibilities of decreasing doping process temperature, increasing process speed, increasing the distribution uniformity of the doping impurity and improves the crystal perfection of the doped layers. The quantitative estimations related to the revealed conditions, are illustrated with an aluminium-silicon example.

Method for Determining the Doping Efficiency of Dispersed Semiconductor Metal Oxide Materials

In this paper, a method for determining the doping efficiency of dispersed semiconductor metal oxide materials is proposed proposing to use the dependences of the free charge carrier concentration, normalized to the concentration of the doping impurity (Ne spec.), on the content of this impurity. The possibilities of this method are demonstrated by the example of studying the effect of technological factors on the efficiency of doping of indium oxide with tin and doping of tin oxide with antimony. It is shown that it is impossible to achieve the concentration of free charge carriers in the ITO material, higher than that in ATO materials, due to the lower solubility of tin in the In2O3 lattice, as compared with the solubility of antimony in the SnO2 lattice.