Group-III Nitrides

Group-III nitrides are wide band gap semiconductors. They find application in the field of optoelectronics. The present work deals with various aspects of chemistry and materials synthesis of group-III nitrides, particularly GaN. The precursor chemistry of group-III nitrides focuses on the synthesis of group-III metal amides. MOCVD of group-III metal amides gave group-III nitride thin films. GaN nanostructures, e.g. nanopillars, nanorods and nanowires, were deposited using Bisazido(diethylaminopropyl)gallium $[(N_{3})_{2}Ga(CH_{2})_{3}NEt_{2}]$ as single molecule precursor. A set of quantitative CVD data, such as temperature distribution, mass flow of precursor and growth rate of GaN was generated to understand the MOCVD of group-III nitrides using single molecule precursor bisazido(dimethylaminopropyl)gallium $[(N_{3})_{2}Ga(CH_{2})_{3}NMe_{2}]$ in a vertical test reactor

Feminism between Judaism and Christianity - A Comparative Study

The study aimed to identify the Jewish feminism and Christian feminism, to address the similarities and differences between feminism in the two religions, and to highlight the most important reasons that called for their emergence. After research and comparison, the researcher found that Jewish feminism is clearly consistent with Christian feminism, especially in the fundamental reasons and motives that led to the emergence of feminist thought in both religions, and in achieving the results of each of them on the religious, social, cultural and political levels. The differences are almost nonexistent and the difference is due to the emergence of each

Synthesis and sensoric response of ZnO decorated carbon nanotubes

ZnO nanoparticles of size 2–10 nm were generated in situ from the single source precursor [2-(methoxyimino)propanoato]zinc(II), ([CH3ONCCH3COO]2Zn·2H2O) onto multiwalled carbon nanotubes (MWCNTs) at low temperature (150 °C). The degree of ZnO coverage on the MWCNTs can be tuned and is dependent upon the ZnO precursor concentration. A plausible growth mechanism based on surface saturation of as-deposited precursor on the MWCNTs has been proposed. The X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) indicate the nano-crystalline nature of the ZnO particles. Scanning electron microscopy (SEM) and TEM investigations of the ZnO deposition revealed a dense and homogeneous deposition along the complete periphery of the MWCNT. The ZnO/MWCNT nanocomposite hybrid materials were further electronically characterized by micro-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-Vis) as well as room temperature photoluminescence (PL). The nanostructured ZnO/MWCNT composite shows a better sensing performance when compared to bare MWCNTs in the detection of low CO levels (20–200 ppm)

Hybrid Architectures from 3D Aligned Arrays of Multiwall Carbon Nanotubes and Nanoparticulate LiCoPO4: Synthesis, Properties and Evaluation of Their Electrochemical Performance as Cathode Materials in Lithium Ion Batteries

Hybrid materials composed of LiMPO4 (M = Fe or Co) with multiwalled carbon nanotubes (MCNTs) were synthesized by tethering lithium phosphoolevins on isolated stochastically disordered MWCNTs as well as on ordered 3D MWCNT arrays via solution based impregnation routes. Ordered 3D arrays of MWCNT monoliths comprising MWCNTs with nominal tube diameters of 60 and 200 nm were synthesized by a catalyst free, template based method, with porous aluminum oxide (PAOX) acting as a template. Consecutive selectiveetching processes gave free standing aligned 3D carbon nanotube (CNT) architectures that were used as supporting cathode structures for electroactive LiCoPO4. LiCoPO4 nanoparticle suspensions derived from an ethanol based organic phosphate source turned out to be superior for the tethering of LiCoPO4 nanoparticles onto the 3D aligned CNT arrays compared to an aqueous based tethering route, thus giving hybrid materials with better electrochemical battery performance compared to materials generated by the latter method. Li ion extraction within the ordered 3D CNT/LiCoPO4 composites seems to be a two-step process and the Li intercalation a one-step process, highlighting the enhanced kinetics of the Li insertion process in the 3D CNT/LixCoPO4 composite in comparison to a particulate mixture of LixCoPO4 that is typically present in a conventional carbon/LiCoPO4 cathode composite system

Binary Au/MWCNT and Ternary Au/ZnO/MWCNT Nanocomposites: Synthesis, Characterisation and Catalytic Performance

Gold nanoparticles of 10-24 and 5-8 nm in size were obtained by chemical citrate reduction and UV photoreduction, respectively, on acid-treated multiwalled carbon nanotubes (MWCNTs) and on ZnO/MWCNT composites. The shape and size of the deposited Au nanoparticles were found to be dependent upon the synthetic method used. Single-crystalline, hexagonal gold particles were produced in the case of UV photoreduction on ZnO/MWCNT, whereas spherical Au particles were deposited on MWCNT when the chemical citrate reduction method was used. In the UV photoreduction route, n-doped ZnO serves as the e- donor, whereas the solvent is the hole trap. All materials were fully characterised by UV/Vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and BET surface analysis. The catalytic activity of the composites was studied for the selective hydrogenation of α,β-unsaturated carbonyl compound 3,7-dimethyl-2,6-octadienal (citral). The Au/ZnO/MWCNT composite favours the formation of unsaturated alcohols (selectivity=50 % at a citral conversion of 20 %) due to the presence of single-crystalline, hexagonal gold particles, whereas saturated aldehyde formation is favoured in the case of the Au/MWCNT nanocomposite that contains spherical gold particles

Selective Adsorption of Volatile Hydrocarbons and Gases in High Surface Area Chalcogels Containing [ES₃]^3– Anions (E = As, Sb)

We describe the sol–gel synthesis of the two new chalcogels KFeSbS₃ and NaFeAsS₃, which demonstrate excellent adsorption selectivity for volatile hydrocarbons and gases. These predominantly mesoporous materials have been synthesized by reacting Fe­(OAc)₂ with K₃SbS₃ or Na₃AsS₃ in a formamide/water mixture at room temperature. Aerogels obtained after supercritical drying have BET surface areas of 636 m²/g and 505 m²/g for KFeSbS₃ and NaFeAsS₃, respectively, with pore sizes in the micro- (below 2 nm), meso- (2–50 nm), and macro- (above 50 nm) regions