Spelling suggestions: "subject:"anda electron microscopy"" "subject:"ando electron microscopy""
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Studies by electron microscopy on the rat bladder epithelium in experimental urolithiasis and hyperplasia /Amanullah. January 1982 (has links)
Thesis--M. Med. Sc., University of Hong Kong, 1982.
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Studies by electron microscopy on the rat bladder epithelium in experimental urolithiasis and hyperplasiaAmanullah. January 1982 (has links)
published_or_final_version / Medical Sciences / Master / Master of Medical Sciences
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Electron microscopy studies of photo-active TiO₂ nanostructuresDivitini, Giorgio January 2013 (has links)
No description available.
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Real time transmission electron microscopy studies of silicon and germanium nanowire growthGamalski, Andrew David January 2012 (has links)
No description available.
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Investigation of plant tissue by environmental scanning electron microscopyZheng, Tao January 2010 (has links)
No description available.
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Ballistic electron emission microscopy of magnetic thin films : simulations and techniquesHandorf, Thomas 05 1900 (has links)
No description available.
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The dendritic growth of γ in astroloyMacia, Mario Luis 12 1900 (has links)
No description available.
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Fibre Bragg grating techniquesBarnier, Fabien January 2000 (has links)
No description available.
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Atomic and electronic structure of grain boundaries in gallium arsenideKrishna, Sujata January 1994 (has links)
HREM imaging was performed using the Jeol 4000ex microscope on specimens prepared from an as-grown ingot of semi-insulating Gallium Arsenide. Various low angle grain boundaries were imaged in the [110] orientation, misorientations varying between 4°-13°. Detailed study of a grain boundary of 11.5° misorientation about the [110] rotation axis has been carried out. Burgers vector analysis showed the presence of perfect 60° and [001] dislocations. Modelling of the [001] dislocation has been carried out using the Tersoff potential, Bond Order Potential and a tight binding Hamiltonian for GaAs, using Chadi (1984) parameters. The dislocation core was associated with an 8-membered and two 5-membered rings. Assum- ing there is a minimum of wrong bonds, we predict that the core has two wrong bonds, one being Ga-Ga, and the other As-As, both in equivalent positions where the two 5-membered rings were appended to the 8-membered ring. The Ga-Ga bond is considerably shorter and hence stronger than the As-As bond. Band structure calculations performed using a Vogl (1983) sp<sup>3</sup>s* Hamiltonian revealed deep states in the gap, which are associated with atoms in the core only. Using Stadelmann's (1987) EMS program, successful image matching of calculated images of the [001] dislocation has been achieved with the experimental image, using the atomic structure generated by tight binding relaxation. Ga and As being only two atomic numbers apart have similar scattering factors and cannot be easily distinguished in the experimental image. The equivalence of the position of the two wrong bonds greatly eases image matching as it is no longer necessary to know which is the Ga-Ga , and which is the As-As bond. This is the first suggested model of the [001] dislocation in GaAs, to the best of my knowledge. It is found to be similar to the atomic structure of the 90° partial dislocation in silicon (Bigger et al., 1992). No account of segregation of impurities to the grain boundary, or the [001] dislocation core is taken here, though it is very likely that an impurity atom would sit itself in this large space. The relaxed atomic structure for the 60° dislocation showed a doubling of periodicity along the dislocation line, similar to that found in the 30° partial in Si. The core consists of a 7-membered and a 5-membered ring with a minimum of two wrong bonds. In addition to this, quantitative comparisons of the [001] HREM image and simulated structures have been made and an iterative structure refinement carried out in order to achieve the best image matching. The resultant 'experimental-best-fit' structure was not found to be physically or chemically plausible.
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Transmission electron microscope studies of emitters of silicon bipolar transistorsGold, Daniel Patrick January 1989 (has links)
Transmission Electron Microscope (TEM) studies have been carried out of emitter regions in polysilicon contacted emitter bipolar transistors. The preparation of suitable TEM thin foils is described. In addition a technique is developed for the observation and quant jtative interpretation of the break-up of the interfacial oxide layers observed in these samples. The effect of annealing the samples prior to emitter dopant implantation (pre-annealing) is investigated for phosphorus and arsenic doped samples, implanted into a polysilicon layer 0.4μm thick, with a dose of 1x10<sup>16</sup>cm<sup>2</sup>. Two wafer pre-cleans have been used prior to polysilicon deposition to produce a thin oxide (0-8Å) and a thicker oxide (14Å). In the presence of the thinner oxide, the phosphorus doped samples enhance epitaxial regrowth of the polysilicon layer compared with the arsenic doped or undoped samples. In the presence of the thicker oxide, no difference is observed between the samples. A mechanism is proposed to explain this. The mechanisms controlling the gain of a phosphorus doped device are investigated and a model proposed to explain the observed electrical characteristics. It is concluded that there are two mechanisms responsible for the observed supression of hole current. Firstly tunnelling through the interfacial oxide and secondly some blocking effect of the interface. Carrier transport in the polysilicon is not believed to contribute to this supression. A dopant sensitive etch has been applied to TEM thin foils containing fully processed emitters in state-of-the-art devices. The shape of the emitter dopant distribution is revealed in such devices for the first time, and a 2-D profile is obtained from the emitter. It is shown that reduction in the emitter depth to 8OOÅ or less does not alter the emitter dopant geometry. The technique is demonstrated to be capable of resolving spatial separations of dopant iso-concentration contours of 100Å or less.
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