Deposition large-area

Intermediate sized photoelectrodes of 25 cm (5x5 cm) were prepared with partial success. Uneven deposits were formed as indicated by patches of discoloration. Initial photocurrents of 75 inA were observed which quickly deteriorated to 1.5 mA. The unsuitability of beaker type preparation conditions is evident for large area deposition. Large area photoelectrode production will require a deposition technique with controlled potential or current. Experiments have shown that with controlled potential CdSe photoelectrodes may be prepared in a more reproducible manner. 

One of the most important factors affecting nodule abundance on the seafloor is the rate of accumulation of their associated sediments, low sedimentation rates favoring high nodule abundances. Areas of the seafloor where sedimentation is rapid are generally only sparsely covered with nodules. For example, most continental margin areas have sedimentation rates that are too rapid for appreciable nodule development, as do turbidite-floored deep-sea abyssal plains. Low rates of sedimentation can result either from a minimal sediment supply to the seafloor or currents inhibiting its deposition. Large areas in the centers of ocean basins receive minimal sediment input. Under these... 

The production of 2D thin layers of particles requires much better control over the thickness of the deposit. In contrast to settling and draining setups, thin liquid film setups deposit large-area films suitable for deposition of particle monolayers. 

N. Chander, P. Singh, A.F. Khan, V. Dutta, V.K. Komarala, Photocurrent enhancement by surface plasmon resonance of gold nanoparticles in spray deposited large area dye sensitized solar cells. Thin Solid Films 568 (2014) 74-80. 

Seam thicknesses and depths vary tremendously. The most favorable deposits have shallow overburdens and thick seams that cover large areas. Acceptable stripping ratios, ie, overburden thickness to coal thickness, depend on the quaHty of the fuel. Ratios up to 10 1 have been used for bituminous coals, but lower ones are required for lignitic coals because of the lower heating value per unit weight. 

Excimer lamps have opened the possibiHty of cost-effective large-area direct photochemical vapor deposition (PCVD). PCVD of stoichiometric, insulating Si02 onto Si wafer has been reported using SiH and N2O as gas-phase precursors and the 172-nm radiation from a Xe 2 lamp (54). Deposition... 

Spray Pyrolysis. In spray pyrolysis, a chemical solution is sprayed on a hot surface where it is pyrolyzed (decomposed) to give thin films of either elements or, more commonly, compounds (22). Eor example, to deposit CdS, a solution of CdCl plus NH2CSNH2 (thiourea) is sprayed on a hot surface. To deposit Iu202, InCl is dissolved in a solvent and sprayed on a hot surface in air. Materials that can be deposited by spray pyrolysis include electrically conductive tin—oxide and indium/tin oxide (ITO), CdS, Cu—InSe2, and CdSe. Spray pyrolysis is an inexpensive deposition process and can be used on large-area substrates. 

The main deposits of freshwater diatomite were laid down in large lakes. Many of these deposits in the western United States formed during glacial times, when the local climate was wetter. Several tens of square kilometers in Nevada west of Tonopah are covered with diatomite as are other large areas in the Great Basin. 

Acid deposition is of greatest concern wherever there are large amounts ol lossil fuel combustion upwind of an area. Eastern North America, large areas of Europe, and eastern Asia all receive acidic deposition. Acidic deposition is especially a concern when poorly buffered soils, with little acid-neutralizing capacity, are impacted. In North America, large areas of eastern Canada, the Adirondack Mountains of upstate New York, and sections of New England all are considered acid sensitive areas, where resistant bedrocks and thin soils prevent significant neutralization of acidity. 

Schafer, L., Saltier, M., and Klages, C. P., Upscaling of the Hot-Filament CVD Process for Deposition of Diamond Films on Large-Area Substrates, m Applications of Diamond Films and Related Materials, (Y. Tzeng, et al., eds.), Elsevier Science Publishers, pp. 453-460(1991)... 

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