Bell Telephone Laboratories

Other

At&t Bell Laboratories

Adam Heller

Barry Irwin Miller

Richard G Vadimsky

Kuang-Chou Chang

Bruce A Parkinson

Yinon Degani

King Lien Tai

Murray Robbins

Harry John Leamy

Ronald J Nelson

Hans J Lewerenz

Paints and coatings involving semiconducting pigments such as titanium dioxide generally degrade because of oxidation of the binder by reactants that are photochemically produced on the pigment surface, and because of direct binder oxidation by charges that are photogenerated in the pigment. In titanium dioxide, this interaction is substantially reduced by avoiding reduced species and by introducing into the titanium dioxide trap states where photogenerated electron-hole pairs recombine by processes such as prolonged milling. Through these expedients, a substantial increase in the stability of the pigment containing composition is obtained.

Process for improving photostability of titanium dioxide pigments in

Semiconductor devices comprising p-type phosphorus containing semiconductor materials chosen from InP, GaP and InGaAsP have chemically treated surfaces comprising a monolayer or less of a metal chosen from silver, ruthenium, gold, platinum, and rhodium. Photoelectrochemical electrodes and Schottky barrier photovoltaic cells made from such treated semiconductors have reduced surface or grain boundary carrier recombination.

Devices having chemically modified p-type InP surfaces

A semiconductor liquid junction photocell having a photovoltaic junction between a p-type photoactive electrode comprising InP or Si and an electrolyte comprising a redox couple selected from the group consisting of V.sup.2+ /V.sup.3+, Nb.sup.4+ /Nb.sup.5+, and Ti.sup.3+ /Ti.sup.4+ produces a stable photocurrent output.

Semiconductor liquid junction photocell having a P-type photoactive

Fabrication of a resist, useful for high resolution pattern delineation and having a silver containing layer on a glassy material, produces better results when the sensitizing bath contains both potassium silver cyanide and a metal cyanide complex capable of providing CN.sup.- ions to shift the equilibrium of Ag(CN).sub.2.sup.- .revreaction.AgCN+CN.sup.- to the left.

Sensitizing bath for silver containing resist

A device having a p-type electrode comprising InP or Si and an electrolyte comprising a redox couple and a hydrogen catalyst evolves hydrogen at the p-type electrode when illuminated.

Device for the photoelectrochemical generation of hydrogen at p-type

Lithographic patterning of particular interest in fabrication of integrated circuitry is based on the photoinduced migration of silver into germanium selenide or other glassy material of appropriate absorption cross section for the chosen actinic radiation. Resists which are negative-acting yield high resolution attributed to initial introduction of the silver in chemically combined form chosen so as to result in formation of a silver compound with a glass component with the compound serving as silver source. Removal of excess silver-containing material is engineered on the basis of the form of silver introduction and results in conversion to a water soluble form. Commercial use will likely be based on an embodiment in which the now developed patterned resist serves as a dry etching mask during delineation of a relatively thick underlying layer of organic material. This procedure is particularly advantageous for use on partially processed circuitry in which prior operations have resulted in surface steps.

Photoinduced migration of silver into chalcogenide layer

Semiconductor devices using chemically treated n-type GaAs have greatly reduced surface recombination velocities. A preferred embodiment uses fractional monolayers of ruthenium on the GaAs surface.

Gallium arsenide devices having reduced surface recombination velocity

A semiconductor liquid junction photocell using a photoactive electrode comprising GaAs has greatly improved solar energy to electrically conversion efficiency when compared to prior art semiconductor liquid junction photocells using GaAs electrodes. The improved efficiency is obtained by material, such as ruthenium, cobalt, rhodium or lead, on the electrode surface. Efficiency is still further increased by texturizing the surface of the GaAs electrode prior to addition of the material. Efficiencies under AM1 conditions are approximately 12 percent.

Semiconductor liquid junction photocell using surface modified GaAs

Liquid-semiconductor photocells using chalcogenide semiconductors have been advanced recently to the point where they compete favorably with silicon devices for solar power conversion. However, in common with silicon devices, the semiconductor needs to be a single crystal. This fact makes solar power impractically expensive. According to this invention, the chalcogenide semiconductor is made by anodizing cadmium or bismuth in a sulfide, selenide or telluride electrolyte. The anodized element, when operated photovoltaically in an electrolyte similar to the anodizing solution, produces useful power conversion and is relatively inexpensive.

Liquid-semiconductor junction photocells

Liquid-semiconductor photocells are described which produce a stable photocurrent output over extended periods of time by controllably removing material from the semiconductor surface in such a manner as to maintain the integrity of the junction characteristics. The removal may be either by photoetching or by chemical reaction with the electrolyte or with agents added to the electrolyte.

Method of operating a liquid-semiconductor junction photocell

Liquid-semiconductor photocells have received attention recently for use in solar power devices. Alternatives to single crystal semiconductors have been sought to reduce the cost of the photocells. According to this invention, the semiconductor is made from a pressure sintered and vapor annealed semiconductor. The electrode is relatively inexpensive to make and the efficiency of the solar cell compares favorably to the efficiency of solar cells using single crystal electrodes.

Liquid-semiconductor photocell using sintered electrode

The ruthenium compound [Ru.sub.2 N(H.sub.2 O).sub.2 Cl.sub.8 ]K.sub.3 is prepared by refluxing a mixture of hydrated water soluble ruthenium chloride, having approximately 40% ruthenium content, and sulphamic acid, the latter having approximately half the molar concentration of the former, for several hours and then precipitating the desired compound by adding solutions of potassium chloride and hydrochloric acid. Electrical contacts on the reeds of sealed reed switches produced by electroplating from an aqueous solution of the salt produced in this manner are found to be particularly resistant to the thermal shock involved in the sealing of the switches.

Articles electrodeposited with ruthenium and processes of producing such

A quality control technique is based on the observation that trapping centers contribute to inefficient operation of junction devices. Devices are irradiated by a first radiation source of intensity sufficient to populate traps and a second radiation source of varying wavelength. Trapping centers are detected by a deviation from the expected photovoltaic output-incident wavelength relationship. Such 'structure' is utilized as the basis for altering production conditions to minimize currents of such centers. While the procedure is of general applicability, it is particularly suitable as applied to photovoltaic cells.

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Bridgewater, NJ, United States of America

Adam Heller