Download or read book Thin films of gallium arsenide on low cost substrates written by Rockwell International. Electronics Research Center and published by . This book was released on 1979 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by Southern Methodist University and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by Rockwell International. Electronics Research Center and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by Ralph Powers Ruth and published by . This book was released on 1980 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by N. J. Nelson and published by . This book was released on 1977 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by N. J. Nelson and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by Ralph Powers Ruth and published by . This book was released on 1979 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The metalorganic chemical vapor deposition (MO-CVD) technique has been applied to the growth of thin films of GaAs and GaAlAs on inexpensive polycrystalline or amorphous substrate materials (glasses, glass-ceramics, alumina ceramics, and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium (TMG), arsine (AsH3), and trimethylaluminum (TMAl) are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperature in the range 600 to 800°C, to produce the desired film composition and properties. Of ten candidate low-cost substrates initially identified for investigation, Corning Code 0317 glass and composites of CVD Ge/glass and sputtered Mo/glass were found to be the most satisfactory, the latter eventually serving as a reference substrate against which to compare the performance of other substrates. Single-crystal window-type solar cells, polycrystalline Schottky-barrier cells, and deposited-junction polycrystalline cells have been grown, fabricated, and characterized. Epitaxial GaAlAs/GaAs p-n junction cells with thin (~500Å) Ga02Al08As windows and GaAs:Zn - GaAs:Se junctions were made with AMO efficiencies as high as 12.8 percent with no AR coating, indicating the high quality of the films grown by the MO-C+VD process. Schottky barrier cells with efficiencies of 2.25 percent AMO (no AR coating) have been made on n/n polycrystalline GaAs structures on Mo/glass composite substrates, with short-circuit current densities up to 12.5 mA/cm2. Also, results of analyses of material and processing costs associated with fabrication of thin-film GaAlAs/GaAs solar cells by the MO-CVD process are discussed.
Download or read book Thin Films of Gallium Arsenide on Low Cost Substrates written by R. P. Ruth and published by . This book was released on 1977 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by Ralph Powers Ruth and published by . This book was released on 1978 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by Ralph Powers Ruth and published by . This book was released on 1978 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by N. J. Nelson and published by . This book was released on 1977 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates written by Ralph Powers Ruth and published by . This book was released on 1978 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates Final Report July 5 1976 July 2 1977 written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The metalorganic chemical vapor deposition (MO-CVD) technique has been applied to the growth of thin films of GaAs and GaAlAs on inexpensive polycrystalline or amorphous substrate materials (glasses, glass-ceramics, alumina ceramics, and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium (TMG), arsine (AsH3), and trimethylaluminum (TMAl) are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperature in the range 600 to 800°C, to produce the desired film composition and properties. Of ten candidate low-cost substrates initially identified for investigation, Corning Code 0317 glass and composites of CVD Ge/glass and sputtered Mo/glass were found to be the most satisfactory, the latter eventually serving as a reference substrate against which to compare the performance of other substrates. Single-crystal window-type solar cells, polycrystalline Schottky-barrier cells, and deposited-junction polycrystalline cells have been grown, fabricated, and characterized. Epitaxial GaAlAs/GaAs p-n junction cells with thin (approx. 500A) Ga0 2Al0 As windows and GaAs:Zn - GaAs:Se junctions were made with AMO efficiencies as high as 12.8 percent with no AR coating. Schottky barrier cells with efficiencies of 2.25 percent AMO (no AR coating) have been made on n/n polycrystalline GaAs structures on Mo/glass composite substrates, with short-circuit current densities up to 12.5 mA/cm2. Also, results of analyses of material and processing costs associated with fabrication of thin-film GaAlAs/GaAs solar cells by the MO-CVD process are discussed.
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates Quarterly Project Report No 2 October 3 1976 January 1 1977 written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The metallorganic chemical vapor deposition (MO-CVD) technique is being applied to the growth of thin films of GaAs and GaAlAs on inexpensive polycrystalline or amorphous substrate materials (glasses, glass-ceramics, alumina ceramics, and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium (TMG), arsine (AsH3), and trimethylaluminum (TMA) are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperatures in the range 600 to 800°C, to produce the desired film composition and properties. The effects of H2 and AsH3 atmospheres at temperatures of 625 to 725°C and the effects of several different cleaning procedures on the surfaces of candidate substrates have been investigated. Composite substrates, consisting of deposited Mo layers on several of the other substrate materials, and deliberately textured glass surfaces have been evaluated for GaAs film growth. Efforts have continued to acquire new or improved materials from various manufacturers for evaluation as possible substrates. A new dedicated reactor system was completed during the quarter and used for growth of undoped GaAs films on single-crystal substrates, to establish and characterize reactor performance, and for growth of Se-doped GaAs films on single-crystal substrates, to establish the n-type doping capabilities of the new reactor. The majority of the MO-CVD experiments, however, have involved the reactor system in use since the program began, and include growth of GaAlAs on single-crystal substrates; growth of polycrystalline GaAs on candidate low-cost substrates; and studies of the nucleation of GaAs on low-cost substrates. Results of these experiments are discussed in detail.
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates Final Technical Report July 5 1976 December 5 1978 written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The MO-CVD technique was applied to the growth of thin films of GaAs and GaAl As on inexpensive polycrystalline or amorphous substrate materials (primarily glasses and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium, arsine, and trimethylaluminum are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperatures of 700 to 750°C, to produce the desired film composition and properties. Studies of the properties of grain boundaries in polycrystalline GaAs films by the use of transport measurements as a function of temperature indicated that the grain boundary regions are depleted of majority carriers by a large density of neutral traps at the grain boundary interface, causing a barrier to majority carrier flow in the material. Schottky-barrier solar cells of approx. 3 percent efficiency (simulated AM0 illumination, no AR coating) were demonstrated on thin-film polycrystalline GaAs n/n/sup +/ structures on Mo sheet, Mo film/glass, and graphite substrates. Substantial enhancement of average grain size in polycrystalline MO-CVD GaAs films on Mo sheet was obtained by the addition of HCl to the growth atmosphere during deposition. Extensive investigation of polycrystalline thin-film p-n junctions indicated that the forward voltage of such devices is apparently limited to 0.5 to 0.6V. A laboratory-type deposition apparatus for the formation of TiO2 antireflection (AR) coatings by pyrolysis of titanium isopropoxide was assembled and tested. Detailed analyses were made of the materials and labor costs involved in the laboratory-scale fabrication of MO-CVD thin-film GaAs solar cells. Details are presented. (WHK).
Download or read book Thin Films of Gallium Arsenide on Low cost Substrates Quarterly Technical Progress Report No 8 and Topical Report No 3 April 2 July 1 1978 written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The seventh quarter of work on the contract is summarized. The metalorganic chemical vapor deposition (MO-CVD) technique has been applied to the growth of thin films of GaAs and GaAlAs on inexpensive polycrystalline or amorphous substrate materials (primarily glasses and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium (TMG), arsine (AsH3), and trimethylaluminum (TMAl) are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperatures of 725 to 750°C, to produce the desired film composition and properties. The technical activities during the quarter were concentrated on (1) a continuing evaluation of various graphite materials as possible substrates for MO-CVD growith of the polycrystalline GaAs solar cells; (2) attempts to improve the quality (especially the grain size) of polycrystalline GaAs films on Mo sheet and Mo/glass substrates by using HCl vapor during the MO-CVD growith process; (3) further studies of the transport properties of polycrystalline GaAs films, wth emphasis on n-type films; (4) continuing investigations of the properties of p-n junctions in polycrystalline GaAs, with emphasis on the formation and properties of p/sup +//n/n/sup +/ deposited structures; and (5) assembling apparatus and establishing a suitable technique for producing TiO2 layers for use as AR coatings on GaAs cells. Progress is reported. (WHK).
