Plasma polymerization is a solventless method for depositing polymeric layers onto any substrate at room temperature. This technique comprises excitation, fragmentation, and polymerization of precursor molecules by an electrical discharge. Although widely used, the fundamental molecular processes associated with plasma polymerization are not fully understood. Basic plasma / polymer interactions were studied by investigating the surface treatment of polytetrafluoroethylene (PTFE) using inert and reactive gas discharges. Depending upon the feed gas employed, chemical, UV, or ion beam modification of the PTFE surface were found to be important. Argon glow discharge treatment was found to result in similar physicochemical phenomena at the PTFE surface to that observed during argon ion beam studies, thereby supporting the relative importance of ion bombardment during noble gas plasma modification. In high power discharges it has been shown that extensive ion bombardment of PTFE can lead to the simultaneous sputtering and plasma polymerization of ejected species onto an adjacent substrate. The chemical nature of the resultant fluorocarbon deposits for various gases was found to correlate to the earlier surface treatment studies. Another way of carrying out plasma polymerization is to use pulsed plasmas; these offer the advantage of greater retention of monomer structure within the plasma polymer matrix. In the case of maleic anhydride less fragmentation of the precursor, reduced beam damage of the polymer, and radically initiated polymerization was observed by increasing the off-period of the pulse. Similarly the structural characteristics of 2- iodothiophene plasma polymers were found to be influenced by the electrical discharge power and pulsing parameters leading to a gradual destruction of the aromatic ring structure.

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No description available.

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<p>The growth of amorphous hydrogenated silicon (a-Si:H) thin films deposided by hot wire chemical vapor deposition (HWCVD) has been studied. The films have been characterised for optical and structural properties by means of UV/VIS,FITR,ERDA, XRD.XTEM and Raman spectroscopy. Low subtrate heater temperatures in the range form 130 to 200 degrees celcius were used in this thesis because it is believed to allow for the deposition of device quality a-Si:H which can be used for electronic photovoltaic devices. Furthermore, low temperatures allows the deposition of a-Si:H on any subtrate and thus offers the possibility of making large area devices on flexible organic substances. We showed that the optical and structural properties of grown a-Si:H films depended critically upon whether the films were produced with silane gas or silane diluted with hydrogen gas. We also showed that it is possible to to deposit crystalline materials at low temperature under high hydrogen dilution ratio of silane gas.</p>

University of Technology Sydney. Faculty of Humanities and Social Sciences. / The growing concern about the role of ethics in western society has also touched documentary film-making. Yet, since the emergence in the late 1980s of the first journal articles discussing documentary ethics, the theoretical exploration of the key arguments in this field has been fitful. Debates amongst filmmakers about ethics are often immersed in topical discussions of production issues or issues relating to a few controversial films. With the exception of a few insightful works, there is little new analysis or examination devoted to exploring ethics in this discipline. This dissertation adds to the available body of work by examining in depth the ethics encountered in the production of a documentary film, Tagged, with young people, especially the ethics encoded in the aesthetic and discursive elements of the film. Theoretical discussions about ethics range from the analytical focus on the ethics of representation, through the use of subjective modes of expressivity and filmic techniques to epistemological analyses of specific issues such as privacy and the nature of consent that draw on legal and medical models. A study of relevant documentary films reveals the variety of approaches to the moral values reflected in their discourses and visual representations, and a range of authorial voices, heavily influenced by the relationship between filmmakers and subjects and by the production circumstances of each film. In Australia, broadcasters, funding bodies and production companies dominate the documentary film-making environment and their codes, editorial policies and protocols influence the whole sector of documentary filmmaking. By categorizing documentary within the broad scope of factual programming, they reflect an institutional gaze that fails to acknowledge those individuals including children and youth, who participate in its production. Through my examination of ethics in both the theory and practice, I address the relevant question of whether there should be a code of practice for documentary film-making. In focussing on my own ethical position and its translation into practice through the making of Tagged, I explore the ways in which the ethical stance that I established is pivotal to the documentary and represented both in the text and in the pragmatic choices of production. This led me to conclude that the development of an ethical position specific to a current project is an effective focus on the potential ethical conflicts in a production. From this I argue that while a broad code of conduct can provide valuable guidelines, it cannot replace the filmmakers’ investigation of their ethical practice and their establishment of an ethical statement and stance for their films thus creating a platform from which ethical conflicts can be understood and either avoided or resolved.

TiO2 films have attracted much attention because of their photoactivity and superhydrophilcity. For the superhydrophilicity studies, most research focused mainly on enhancing superhydrophilicity of Ti02 film under UV illumination. A hydrothermal-dip-coating superwetting TiO2 film was synthesised and found to preserve its superhydrophilicity up to 6 months. This non-UV superwetting TI02 film potentially opens an alternative application as bioactive layer for growing hydroxyapatite (HAP) coating, used extensively as prosthetic device medically. In this research, a systematic study was carried out, aiming to understand and optimise the hydrophilicity and superwetting properties of Ti O2 film without UV illumination. The effect of (i) PEG concentration, (ii) film thickness and (iii) agglomerate size of TiO2 on the wettability of TiO2 film was investigated. Although the presence of PEG does affect the porosity of the film, PEG concentration does not play significant role in retaining superhydrophilicity of the film. The evidence from AFM showed that surface roughness is the key parameter to control in order to retain the superhydrophilic wetting and antifogging behavior of the synthesised films, which can be tuned by simple manipulation of the multilayer assembled of TiO2 nanoparticles through varying the film thickness and agglomerate size. A film thickness of (????140nm) yielded the optimum roughness (rms =23nm) for the creation of the best superhydrophilic wetting behavior. Thicker films smoothened the film roughness, and therefore causing detrimental effects on their superhydrophilic wetting properties. Smaller agglomerate size was also found to be important in retaining the roughness film. The photoactivity of the "non UV illuminated"superhydrophilic film was found that be comparable with a Pilkington Activ??? in degrading methyl blue. The growth of Hydroxyapatite (HAP), synthesised via organic-inorganic hybrid method, and the mechanical stability of the HAP coating on the TiO2 films applied on titanium foil were studied. Homogenous HAP coating was found to grow only on the T O2 film with superhydrophilic properties. However the coating was of poor mechanical stability. Surface -OH was found to play an important role in aligning the phosphonate groups in HAP recursor during dip-coating.

Polycrystalline silicon (pc-Si, grain size > 1??m, no amorphous tissue) on glass is an interesting material for thin-film solar cells due to the low costs, the abundance and the non-toxic character of Si, and the properties of pc-Si like long-term stability and lateral conductance. Glass as supporting material significantly complicates the fabrication process as it limits the thermal budget and the maximum temperature. In this work, the feasibility of forming large-grained pc-Si thin-film solar cells on glass by ion-assisted deposition (IAD) on aluminium-induced crystallisation (AIC) seed layers (ALICIA solar cells) is investigated. IAD allows epitaxial growth at high rate, and being based on evaporation, is of low cost (high source material usage, no toxic gases involved). High-quality epitaxy on (100)-oriented Si wafer substrates is demonstrated in a non{UHV environment, to further increase its industrial appli- cability. High{rate growth and a sacrificial protective layer control contamination problems associated with the non-UHV environment. The process is then trans- ferred to AIC-seeded glass and optimised, with particular focus on the influence of the glass. Using high-temperature rapid thermal annealing and hydrogenation as post-deposition treatments, ALICIA solar cells with a 1-Sun open-circuit voltage of 420 mV are achieved. Moreover, two novel characterisation techniques are presented. One allows the fast and non-destructive assessment of the structural quality of pc-Si films using opti- cal measurements. Furthermore, `impedance analysis', a novel capacitance-voltage measurement technique based on impedance spectroscopy, is presented. It allows the reliable determination of the absorber layer doping density and the built{in potential of non-ideal p-n junction solar cells. The latter is used to investigate the influence of post{deposition treatments on the n-type absorber layer doping of ALICIA solar cells. It is found, using temperature dependent impedance analysis, that unintentional doping and defects have a strong influence on the absorber layer doping. A maximum in the short-circuit current density of ALICIA solar cells is found for phosphorus concentrations in the absorber of 1??1017 cm??3. For such ALI- CIA cells a base difusion length in the range 600 - 950nm, a short{circuit current density in the range 10 - 13.5 mA/cm2 and an energy conversion efficiency of 2.2% are obtained.

147 leaves : ill., photos ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1976

Polycrystalline silicon (pc-Si, grain size > 1??m, no amorphous tissue) on glass is an interesting material for thin-film solar cells due to the low costs, the abundance and the non-toxic character of Si, and the properties of pc-Si like long-term stability and lateral conductance. Glass as supporting material significantly complicates the fabrication process as it limits the thermal budget and the maximum temperature. In this work, the feasibility of forming large-grained pc-Si thin-film solar cells on glass by ion-assisted deposition (IAD) on aluminium-induced crystallisation (AIC) seed layers (ALICIA solar cells) is investigated. IAD allows epitaxial growth at high rate, and being based on evaporation, is of low cost (high source material usage, no toxic gases involved). High-quality epitaxy on (100)-oriented Si wafer substrates is demonstrated in a non{UHV environment, to further increase its industrial appli- cability. High{rate growth and a sacrificial protective layer control contamination problems associated with the non-UHV environment. The process is then trans- ferred to AIC-seeded glass and optimised, with particular focus on the influence of the glass. Using high-temperature rapid thermal annealing and hydrogenation as post-deposition treatments, ALICIA solar cells with a 1-Sun open-circuit voltage of 420 mV are achieved. Moreover, two novel characterisation techniques are presented. One allows the fast and non-destructive assessment of the structural quality of pc-Si films using opti- cal measurements. Furthermore, `impedance analysis', a novel capacitance-voltage measurement technique based on impedance spectroscopy, is presented. It allows the reliable determination of the absorber layer doping density and the built{in potential of non-ideal p-n junction solar cells. The latter is used to investigate the influence of post{deposition treatments on the n-type absorber layer doping of ALICIA solar cells. It is found, using temperature dependent impedance analysis, that unintentional doping and defects have a strong influence on the absorber layer doping. A maximum in the short-circuit current density of ALICIA solar cells is found for phosphorus concentrations in the absorber of 1??1017 cm??3. For such ALI- CIA cells a base difusion length in the range 600 - 950nm, a short{circuit current density in the range 10 - 13.5 mA/cm2 and an energy conversion efficiency of 2.2% are obtained.