High resolution resonance ionization spectroscopy of stable titanium isotopes ( 46-50 Ti) using an injection-locked Ti:Sapphire laser system was developed. Five peaks corresponding to the isotopes 46-50 Ti were clearly resolved in the spectra with a line-width of 160 MHz. Isotope shifts of the 365.4537 nm transition were measured.
This study investigated the formation of carbon films on a stainless steel surface using cathodic reduction of CO 3 2-ions in a molten chloride. Various electrolysis methods such as potentiostatic, galvanostatic, galvanostatic pulse, and galvanostatic periodically reversed (PR) electrolysis were used with the aim of obtaining smooth and adhesive films. Potentiostatic and galvanostatic PR electrolysis yielded smooth, dense, and adhesive carbon films, but the electrodeposited carbon films created by potentiostatic electrolysis often peeled away from the substrate when the supplied electricity was increased, possibly because of selective particle growth on the initially deposited, randomly dispersed carbon nucleation sites. However, galvanostatic PR electrolysis produced smooth and adhesive carbon films for which the thickness increased almost linearly along with the supplied electricity. These results suggest that galvanostatic PR electrolysis is the most effective electrolysis method for obtaining smooth, dense, and adhesive carbon films.
In conventional positron annihilation spectroscopy using radioisotopes, source contributions are unavoidable since positrons annihilate in the material covering the radioisotopes. Part of the positrons annihilate within the radioisotopes even when radioisotopes are deposited directly on a sample. Gamma-ray-induced positron annihilation spectroscopy makes it possible to measure only the spectra of a sample without source contributions since positrons are directly generated inside the sample from the gamma rays by pair production and annihilate inside the same sample. In this study, a new positron age–momentum correlation measurement system using ultrashort pulsed gamma rays is developed. The gamma rays with an energy of 6.6 MeV are generated by the inverse Thomson scattering of laser photons by high-energy electrons and are irradiated to the sample. The laser pulse can fully control the timing of gamma-ray generation. This characteristic and the use of a digital oscilloscope with a 12-bit vertical resolution enable us to develop a simple measurement system. Time-resolved momentum distributions for stainless steel with no defects and deformed interstitial free steel show the explicit differences reflecting the type of defect; for BaF2 single crystals, the results have been interpreted by considering the formation of positronium.
In sputtering deposition process of TiO 2 , metal Ti or sintered TiO 2 target is used as deposition source. In this study, we have compared the characteristic of target materials. When TiO 2 target was used, stoichiometric TiO 2 films was deposited under the Ar atmosphere containing 1.0% of oxygen. The highest sputtering rate under this atmosphere was 3.9nm/min at 3.4W/cm 2 . But, sintered TiO 2 target is fragile and cannot endure higher density of input power than 3.4W/cm 2 . On the other hand, Ti target needs higher oxygen concentration (8%) in sputtering gas atmosphere for obtaining rutile/anatase. Even though Ti target can be input twice power density of 7.9W/cm 2 , the highest deposition rate for Ti target was 1.4/nm, which was ∼35% of the highest rate for TiO 2 target. Then we have study out the composite target consisting of Ti plate and TiO 2 chips. Using the composite target, stoichiometric TiO 2 films were prepared in the rate of 9.6nm/min at 6.8 W/cm 2 under the atmosphere of Ar/2.5%O 2 . Furthermore, we have found that the TiO 2 films obtained from the composite target consisted of about 100% anatase, whereas TiO 2 films obtained from other target have rutile dominant structure. The optical band gap energy of the film is determined by using the Tauc plot. The calculated band gap energies for the films deposited by Ti target and composite target were 2.95 and 3.24eV, which are equivalent to that of rutile and anatase structure, respectively.Keywords: TiO 2 , Rutile, Anatase, sputtering, XRD W procesie nanoszenia TiO 2 metodą rozpylania, jako tarczy używano metalicznego Ti lub spiekanego TiO 2 . W pracy dokonano porównania obu materiałów. W przypadku zastosowania jako tarczy TiO 2 przy nanoszeniu w atmosferze Ar zawierającym 1,0% tlenu otrzymano stechiometryczną warstwę TiO 2 . Największa uzyskana szybkość rozpylania w tej atmosferze wyniosła 3,9 nm/min przy gęstości mocy wejściowej 3,4 W/cm 2 . Jednak spiekany TiO 2 jest kruchy i nie wytrzymuje gęstości mocy wejściowej powyżej 3,4 W/cm 2 . Z drugiej strony, przy rozpylaniu z tarczy Ti konieczne jest zwiększone stężenie tlenu (8%) w atmosferze aby otrzymać fazę rutyl/anataz. Mimo że tarcza Ti wytrzymuje gęstość mocy dwa razy wyższą niż TiO 2 (7,9 W/cm 2 ), największa uzyskana szybkość rozpylania wynosiła 1,4 nm/min, co stanowi ∼35% najwyższej szybkości uzyskanej dla tarczy TiO 2 . Zbadano także tarczę kompozytową składające się z płyty Ti oraz wiórów TiO 2 . W przypadku zastosowania tarczy kompozytowej, szybkość rozpylania wyniosła 9,6 nm/min przy mocy 6,8 W/cm 2 w atmosferze Ar/2,5%O 2 . Dodatkowo, warstwy TiO 2 otrzymane z tarczy kompozytowej zawierały około 100% anatazu, podczas gdy w przypadku warstw otrzymanych z pozostałych tarcz dominowała faza rutylu. Szerokość przerwy energetycznej wyznaczono na podstawie wykresu Tauca. Obliczone wartości przerwy energetycznej wynosiły 2,95 eV dla podłoża Ti i 3,24 eV dla podłoża kompozytowego, co odpowiada wartością przerw odpowiednio dla rutylu i anatazu.
This study investigates the preparation of Ge/TiO 2 multi-layer films using a differentialpumping co-sputtering system (DPCS). This system has two chambers with different atmospheres, pure Ar for the Ge target and 0.5 %O 2 in Ar for the TiO 2 ceramic target. The optical absorption spectra of the multi-layer films obviously shift to visible and near-infrared regions with increasing Ge layer thickness, while keeping O/Ti composition ratios of 2.30.1 in TiO 2 . X-ray diffraction results indicate that the TiO 2 layer forms a single-phase anatase structure in the multi-layer films.X-ray photoelectron spectroscopy also indicates that metallic Ge is dominant in the multi-layer film with negligible Ge-oxide. Therefore, DPCS provides a multi-layer film with a single-phase anatase structure in the TiO 2 layer and a dominant metallic element in the Ge layer.
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