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Full-Text Articles in Engineering

Characterization Of Cadmium Sulfide Films Deposited By Chemical Bath Method, Quazi Galib Samdami, Hameed A. Naseem, W. D. Brown Jan 1995

Characterization Of Cadmium Sulfide Films Deposited By Chemical Bath Method, Quazi Galib Samdami, Hameed A. Naseem, W. D. Brown

Journal of the Arkansas Academy of Science

Thin filmcadmium sulfide is a leading candidate in the fabrication of large area solar cells. The chemical bath deposition method is one of the least expensive sources for the fabrication of device quality cadmium sulfide thin films.Inthe present work, the deposition of CdS films on glass substrate from an aqueous solution containing cadmium acetate, ammonia, ammonium acetate, and thiourea are investigated. The structural properties of CdS films are characterized. Good quality thin films within 0.1 - o.5 |im thickness were obtained in30 minute deposition time, and at 70*-90*C. The films show preferential orientations. The optical transmittance of the films are …


Retrieval Of Atmospheric Turbidity Coefficiant And Water Column Density Fro Solar Irradiance Data, Felix Tendeku Jan 1995

Retrieval Of Atmospheric Turbidity Coefficiant And Water Column Density Fro Solar Irradiance Data, Felix Tendeku

Journal of the Arkansas Academy of Science

Ground-based measurement of solar irradiance has been made using a spectroradiometer at wavelengths inapx-water absorption band. An algorithm is formulated to retrieve simultaneously the atmospheic water column density and Angstrom's turbidity coefficient. The transmission models used to account for the contribution from diverse atmospheic absorbing and scattering elements are presented.


Diagnostics Of Cdte Electrodeposition By Rest Potential Voltammetry, Brandon Kemp, Robert Engelken, Arif Raza, Arees Siddiqui, Omer Mustafa Jan 1995

Diagnostics Of Cdte Electrodeposition By Rest Potential Voltammetry, Brandon Kemp, Robert Engelken, Arif Raza, Arees Siddiqui, Omer Mustafa

Journal of the Arkansas Academy of Science

Due to the extreme sensitivity of the partial elemental currents (i.e.,iCd, iTe) and, hence, stoichiometry to deposition voltage, temperature, mass transport, and ambient light intensity during electrodeposition of semiconductor films, it is important to implement in-situ methods for monitoring the stoichiometry and related semiconductor efficacy of the growing film. We report investigation of open circuit rest potential (Eoc) voltammetry as one such method during electrodeposition of CdTe from aprotic electrolytes such as ethylene glycol. Plots of transient open circuit potential versus sweep voltage exhibit distinct transition and plateau structures corresponding to Te, CdTe, and Cd phases and correlating with the …


Construction Resource Allocation Using A Genetic Algorithm, Siripong Malasri, Jennifer R. Martin Jan 1995

Construction Resource Allocation Using A Genetic Algorithm, Siripong Malasri, Jennifer R. Martin

Journal of the Arkansas Academy of Science

A proper allocation of limited resources (men, machines, materials, and money) is critical in a construction project. Traditionally, resource allocation problems have been solved using methods in operations research (OR), such as mathematical programming. In recent years, genetic algorithms (GA) have emerged as an effective optimization methodology. One major advantage of the GA approach over the OR approach is that the GA approach is universal for various types of optimization problems, unlike the OR approach which varies depending on the types of problems at hand. This paper shows an application of GA to a resource allocation problem in the construction …


Polishing Of Cvd-Diamond Substrates Using Reactive Ion Etching, Gopi M.R. Sirineni, Hameed A. Naseem, W. D. Brown, A. P. Malshe Jan 1995

Polishing Of Cvd-Diamond Substrates Using Reactive Ion Etching, Gopi M.R. Sirineni, Hameed A. Naseem, W. D. Brown, A. P. Malshe

Journal of the Arkansas Academy of Science

Multichip modules (MCM)have proved to be a viable packaging technology for achieving small size and high performance. By their nature, MCMs typically integrate multiple bare die into a module that can be the plastic or ceramic package. As a result, the MCMrequires an efficient mechanism for removing excess heat. Diamond with its excellent thermal conductivity, is the ideal choice as a substrate material for these applications. Chemical vapor deposited (CVD) diamond substrates makes possible the practical realization of a novel diamond based 3-D MCM. However, the diamond films grown by CVD technique are polycrystalline and have non-uniform filmroughness and randomly …


Molten Salt Electrolytes For Electrodeposition Of Cdte Films, Arif Raza, Robert Engelken, Brandon Kemp, Arees Siddiqui, Omer Mustafa Jan 1995

Molten Salt Electrolytes For Electrodeposition Of Cdte Films, Arif Raza, Robert Engelken, Brandon Kemp, Arees Siddiqui, Omer Mustafa

Journal of the Arkansas Academy of Science

We report preliminary investigation of several molten salt electrolytes containing CdCl2 and TeCl4 for the electrodeposition of CdTe films at temperatures well above (>250 °C) those used with aqueous and organic electrolytes. These high temperatures have potential todramatically increase the crystallite size (Poole, Engelken, et al., 1994), as is important for optoelectronic device applications of CdTe, a leading II-VIsemiconductor. This paper willsurvey the results obtained withelectrolytes such as B2O,/HBO2 (m.p. - 230'C), NaCH3COO (m.p. » 324°C), ZnCl2 (m.p. - 283*C), and LiCl/KCl (m.p. * 350 °C), with an emphasis on the latter two. Key material to be presented includes …