The influence of surface chemical treatments and of deposition of a SiO2 surface passivation layer on carrier distributions and mobility in AlxGa12xN/GaN heterostructure field-effect-transistor epitaxial layer structures is investigated. Surface chemical treatments are found to exert little influence on carrier distribution and mobility. Deposition of a SiO2 surface passivation layer is found t...

Ta2O5∕SiO2 high reflection (HR) interference coatings for λ ∼ 1 μm offer superior performance at high irradiance conditions. However, these coatings are not good candidates for high peak power conditions in comparison toHfO2∕SiO2 multilayer stacks. Here we show that the modification of the top layers design of a quarter wave Ta2O5∕SiO2 high reflector leads to 4–5 fold increase in the laser dama...

The effect of TiO2 layer applied to the conventional Fe2O3/FTO photoanode to improve the photoelectrochemical performance was assessed from the viewpoint of the microstructure and energy band structure. Regardless of the location of the TiO2 layer in the photoanodes, that is, Fe2O3/TiO2/FTO or TiO2/Fe2O3/FTO, high performance was obtained when α-Fe2O3 and H-TiNT/anatase-TiO2 phases existed in t...

Elektrokinetické vlastnosti zmesí minerálov Elektroforetický rozptyl svetla (ELS) je nová experimentálna technika umožňujúca merať spectrum elektroforetickej pohyblivosti alebo zeta (ξ) potenciálu skupiny častíc. Toto spectrum odráža distribúciu náboja a čiastočne distribúciu rozmeru týchto častíc. Avšak, okrem modálnej hodnoty napr. zeta potenciálu častíc rovnakého druhu, z ELS spektra môžeme ...

SiO2 /Ge:SiO2 /SiO2 sandwiched structure was fabricated for exploring efficient light emission. After annealed in N2 (O2,1%), this structure shows three photoluminescence ~PL! bands at 293, 395, and 780 nm. The intensity of the 395 nm band is largely enhanced in comparison with that from the monolayered Ge:SiO2 film. Spectral analyses suggest that the three PL bands originate from S1→S0 , T((T)...

Hydrogen in the Earth's deep interior has been thought to exist as a hydroxyl group in high-pressure minerals. We present Muon Spin Rotation experiments on SiO2 stishovite, which is an archetypal high-pressure mineral. Positive muon (which can be considered as a light isotope of proton) implanted in stishovite was found to capture electron to form muonium (corresponding to neutral hydrogen). Th...

Magnetic nanoparticles with attractive optical properties have been proposed for applications in such areas as separation and magnetic resonance imaging. In this paper, a simple and novel fluorescent sensor of Zn2+ was designed with 3,5-di-tert-butyl-2-hydroxybenzaldehyde [DTH] covalently grafted onto the surface of magnetic core/shell Fe3O4@SiO2 nanoparticles [NPs] (DTH-Fe3O4@SiO2 NPs) using t...

A novel sonochemical approach was developed for the synthesis of different core/shell structures of Fe3O4/SiO2/Ag nanocubes and SiO2/Ag nanospheres. The total reaction time of the three sonochemical steps for the synthesis of Fe3O4/SiO2/Ag nanocubes is shorter than that of the previously reported methods. A proposed reaction mechanism for the sonochemical functionalization of the silica and the...

We report the synthesis of a new Au nanocatalyst with increased thermal stability. This catalyst system consisted of gold nanoparticles attached to functionalized TiO2/SiO2 core-shell nanocomposites, together with the encapsulation of mesoporous silica. The synthesis process mainly involved four steps, which included the synthesis of the TiO2/SiO2 core-shell composites, synthesis of the Au/TiO2...

This study investigates an advanced copper (Cu) chemical displacement technique (CDT) with varying the chemical displacement time for fabricating Cu/SiO2-stacked resistive random-access memory (ReRAM). Compared with other Cu deposition methods, this CDT easily controls the interface of the Cu-insulator, the switching layer thickness, and the immunity of the Cu etching process, assisting the 1-t...