The Standard Oil Company

Monosolar Inc.

Bp Solar International LLC

Standard Oil Commercial Development Company

Sohio Commercial Development Co.

The Standard Oil Company (ohio)

Bp Photovoltaics, Ltd.

Bulent M Basol

Eric S Tseng

William J Biter

Dennis S Lo

Robert L Rod

Novel ohmic contacts are provided for p-type semiconductor compounds comprising at least one of the metals of Class IIB of the Periodic Table of Elements and one of the non-metal elements of Class VIA of the Periodic Table of Elements, as well as a method for forming such novel ohmic contacts. These ohmic contacts comprise a multilayer metal contact wherein the first layer provides a lasting stable contact with the p-type semiconductor; the additional layers provide the necessary electrical conductivity for the contact to be efficient.

Multilayer ohmic contact for p-type semiconductor and method of making

A stable front contact current collector grid 36 is provided for thin-film photovoltaic devices. The current collector grid 36 is deposited on a textured patterned surface 35 of an optically transparent electrically conductive layer 34 that insures stable bonding between the current collector grid 36 and the transparent conductive layer 34. The photovoltaic device 30 includes a substrate 32; an optically transparent electrically conductive layer 34 having a textured patterned surface 35; a front contact current collector grid 36; a first semiconductor layer 38; a second semiconductor layer 40; and an electrically conductive film 42 in contact with the second semiconductor layer.

Stable contact between current collector grid and transparent conductive

A method of making an ohmic content to a thin film of a II-VI compound semiconductor. The contact is made by etching the film with an acidic solution and thereafter treating the etched surface with an alkaline solution. A layer of copper 5 to 50 angstroms thick is deposited on the etched and treated surface and covered by a different metal. The contact may be heat treated to improve its performance.

Method of making multilayer ohmic contact to thin film p-type II-VI

A large area, thin-film photovoltaic device 30 having a transparent front contact 32 is made more efficient by the use of a current collector grid 36. The current collector grid 36 is embedded in an optically transparent electrically conductive layer 34 and may extend partially into a substrate 32 or partially into a first semiconductor layer 38. The process for preparing such thin-film photovoltaic devices includes forming channels in the optically transparent electrically conductive layer 34 and depositing the current collector grid material in the channels. By this design, problems encountered in the deposition of thin-film semiconductor layers due to the presence of relatively large current collector grids are effectively eliminated.

Stable front contact current collector for photovoltaic devices and

Thin films of Hg.sub.1-x Cd.sub.x Te with controlled x greater than 0.5 are cathodically deposited on a thin CdS film over a conductive film of ITO deposited on a glass substrate. Depositing a conductive film on the electrodeposited Hg.sub.1-x Cd.sub.x Te treated to provide a Te-rich surface for a good ohmic contact forms an improved solar cell.

Thin film heterojunction photovoltaic devices

A large area photovoltaic device having a transparent front contact is made more efficient by a current collector grid formed over the transparent front contact to decrease the series resistance of the device. Where the front contact is between a transparent substrate and the semiconductor layers of the photovoltaic device, the collector grid is embedded in the semiconductor layers. To prevent leakage of current into the collector grid from one semiconductor layer, the collector grid material is selected to form a Schottky barrier junction with that semiconductor layer that blocks the flow of the leakage current. The process for preparing such thin film photovoltaic devices includes etching channels in the semiconductor layers, depositing the collector grid material in the channels, insulating the grid, and depositing a back electrical contact film. This process has several advantages, particularly when those materials for the collector grid are not compatible with the deposition processes of the semiconductor layers.

Method of making current collector grid and materials therefor

A stable front contact current collector grid 116 is provided for photovoltaic devices. The current collector grid 116 is disposed between two semiconductor layers, 118 and 119, each semiconductor layer having the same conductivity type. The photovoltaic device utilizes a substrate 112; an optically transparent electrically conductive layer 114; a first layer of semiconductor material 118; a front contact current collector grid 116; a second layer of semiconductor material 119 having the same conductivity type as the first semiconductor layer; a third layer of semiconductor material 120 having a conductivity type opposite from that of the first and second semiconductor layers; and an electrically conductive film 122 in contact with the third semiconductor layer.

Thin-film photovoltaic devices incorporating current collector grid and

Electrodeposition of thin film heterojunction photovoltaic devices that

A method of forming ohmic contacts with thin film p-type semiconductor Class II B - VI A compounds comprising etching the film surface with an acidic solution, then etching with a strong basic solution and finally depositing a conductive metal layer.

Method of forming ohmic contacts

A method of fabricating a thin film heterojunction photovoltaic cell which comprises depositing a film of a near intrinsic or n-type semiconductor compound formed of at least one of the metal elements of Class II B of the Periodic Table of Elements and at least tellurium and then heating said film at a temperature between about 250.degree. C. and 500.degree. C. for a time sufficient to convert said film to a suitably low resistivity p-type semiconductor compound. Such film may be deposited initially on the surface of an n-type semiconductor substrate. Alternatively, there may be deposited on the converted film a layer of n-type semiconductor compound different from the film semiconductor compound. The resulting photovoltaic cell exhibits a substantially increased power output over similar cells not subjected to the method of the present invention.

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Los Angeles, CA, United States of America

Bulent M Basol