Atomic Layer Deposition for optical applications: metal fluoride thin films and novel devices

Thin films of various metal fluorides are suited for optical coatings from infrared (IR) to ultraviolet (UV) range due to their excellent light transmission. In this work, novel metal fluoride processes have been developed for atomic layer deposition (ALD), which is a gas phase thin film deposition method based on alternate saturative surface reactions. Surface controlled self-limiting film growth results in conformal and uniform films. Other strengths of ALD are precise film thickness control, repeatability and dense and pinhole free films. All these make the ALD technique an ideal choice also for depositing metal fluoride thin films. Metal fluoride ALD processes have been largely missing, which is mostly due to a lack of a good fluorine precursor. In this thesis, TiF4 precursor was used for the first time as the fluorine source in ALD for depositing CaF2, MgF2, LaF3 and YF3 thin films. TaF5 was studied as an alternative novel fluorine precursor only for MgF2 thin films. Metal-thd (thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) compounds were applied as the metal precursors. The films were grown at 175 450 °C and they were characterized by various methods. The metal fluoride films grown at higher temperatures had generally lower impurity contents with higher UV light transmittances, but increased roughness caused more scattering losses. The highest transmittances and low refractive indices below 1.4 (at 580 nm) were obtained with MgF2 samples. MgF2 grown from TaF5 precursor showed even better UV light transmittance than MgF2 grown from TiF4. Thus, TaF5 can be considered as a high quality fluorine precursor for depositing metal fluoride thin films. Finally, MgF2 films were applied in fabrication of high reflecting mirrors together with Ta2O5 films for visible region and with LaF3 films for UV region. Another part of the thesis consists of applying already existing ALD processes for novel optical devices. In addition to the high reflecting mirrors, a thin ALD Al2O3 film on top of a silver coating was proven to protect the silver mirror coating from tarnishing. Iridium grid filter prototype for rejecting IR light and Ir-coated micro channel plates for focusing x-rays were successfully fabricated. Finally, Ir-coated Fresnel zone plates were shown to provide the best spatial resolution up to date in scanning x-ray microscopy.

Australian feature films and distribution: Industry or cottage industry?

Feature films remain critical flagships to any national film industry. Australian feature films can be highly commercial endeavours that also perform symbolic functions by embodying the national imaginary in big screen based sound and imagery. They conduct a dialogue with domestic audiences as well as showcase key aspects of Australia in the global film festival circuit. As the pre-eminent filmmaking form, feature films also serve as important launchpads for the careers of many Australian writers, directors, actors and technical crew. In the wake of over a decade of diminished share of local box office obtained by Australian feature films, Australian Feature Films and Distribution: Industry or cottage industry, examines issues in the production sector affecting the performance of Australian feature films and some responses by the central funding and support screen agency, Screen Australia.

Electrical and optical properties of amorphous semiconducting GeSe and GeSbSe films

The electrical activation energy and optical band-gap of GeSe and GeSbSe thin films prepared by flash evaporation on to glass substrates have been determined. The conductivities of the films were found to be given by Image , the activation energy Ea being 0.53 eV and 0.40 eV for GeSe and GeSbSe respectively. The optical absorption constant α near the absorption edge could be described by Image from which the optical band-gaps E0 were found to be 1.01 eV for GeSe and 0.67 eV for GeSbSe at 300°K. At 110°K the corresponding values of E0 were 1.07 eV and 0.735 eV respectively. The significance of these values is discussed in relation to those of other amorphous semiconductors.

Plan zemelʻnogo otvoda kolfonda "Novai︠a︡ Zhiznʻ" Krivorogskogo okruga Mikhaĭlovskogo raĭona ploshchadi︠u︡ 303 desi︠a︡tin

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Plan zemelʻnogo otvoda kollektiva "Tagancha" Krivorogskogo okruga Sofievskogo raĭona ploshchadi︠u︡ 498 desi︠a︡tin

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Plan uchastka kolfonda "Zh" Mikhaĭlovskogo raĭona Krivorogskogo okruga ploshchadiʻ︠u︡ 868 desi︠a︡tin

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Plan uchastka kolfonda "A" Krivorogskogo okruga Mikhaĭlovskogo raĭona ploshchadiʻ︠u︡ 861 desi︠a︡tin

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Plan zemelʻnogo otvoda uchastka lit. "K" kollektivov "Kalininovka" i "Novai︠a︡ Zhiznʻ" Krivorogskogo okruga Sofievskogo raĭona ploshchadiʻ︠u︡ 569 desi︠a︡tin

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Plan uchastka gosfonda kollektiva "Trud" Krivorogskogo okruga i raĭona ploshchadiʻ︠u︡ 107 desi︠a︡tin

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Plan kolfonda Nº 101, Krivorogskogo okruga Bozhedarovkogo raĭona, ploshchadiʻ︠u︡ 1366 desi︠a︡tin

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Plan uchastka kolfonda litera "D" Krivorogskogo okruga Mikhăilovskogo raĭona, ploshchadiʻ︠u︡ 874 desi︠a︡tin

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