Browsing by Author "Minani, Evariste"

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    Growth temperature and microstructural differences in hydrogenated amorphous silicon deposited on glass substrates
    (2002) Minani, Evariste; Härting, Margit; Britton, David T
    Hydrogenated amorphous silicon (a-Si:H) is an important thin film semiconductor with a wide variety of applications in microelectronics and optoelectronics. However, it is metastable and photodegrades after a moderate light illumination (Staebler-Wronski effect). The most stable material has been suggested to be at the edge of crystallinity with microcrystalline inclusions. Using a combination of positron annihilation and X-ray diffraction techniques, the microstructure of hydrogenated amorphous silicon grown by hot wire chemical vapour deposition on glass substrates at different substrate temperatures ranging between 300°C and 500 °C is examined. In previous studies the crystallisation was accompanied by a relaxation of defect structure with an increase in free volume at positron annihilation site. In this work, both techniques show a relaxation of the network with increasing growth temperature, leading to a higher degree of ordering, shorter bond lengths, and a reduction in the average size of defects in the material.
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    Microstructure, stress and defect evolution under illumination in hydrogenated amorphous silicon (a-Si:H)
    (2008) Minani, Evariste; Britton, David T; Härting, Margit
    The purpose of this study is firstly to investigate the relation between microstructure, stress and hydrogen distribution in as deposited hydrogenated amorphous silicon (a-Si:H) layers, and secondly the investigation of the influence of illumination on hydrogen evolution and its relationship with the strain in illuminated layers.