The Standard Oil Company

William J Biter

Bulent M Basol

Eric S Tseng

Louis F Szabo

Gerald P Ceasar

A stable ohmic contact for thin films of p-type tellurium-containing II-VI semiconductors and photovoltaic devices incorporating such contacts. An ohmic contact according to the invention includes a contact-forming layer deposited on a p-type thin film of a tellurium-contacting II-VI semiconductor. Preferably, the contact-forming layer is copper having a thickness of about 2 nanometers. An isolation layer is deposited on the contact-forming to isolate subsequently deposited layers from the thin film. The isolation layer may be carbon or a thin layer of nickel. A connection layer for attaching an external electrical conductor is deposited on the isolation layer. The connection layer may be aluminum, chromium or a layer of copper, provided a copper layer is covered with one of silver, aluminum or a thin layer of nickel, preferably covered with aluminum. The stable, ohmic contact may be used as a back contact in a photovoltaic device incorporating a thin film of a tellurium-containing II-VI semiconductor as one of the active semiconductor layers in the device.

Stable ohmic contacts to thin films of p-type tellurium-containing II-VI

A two terminal, multiple cell photovoltaic device, each including materials having mutually imcompatible preparatory processes, is manufactured by separately forming the cells on substrates and adhering the cells with a light-transmissive, electrically conductive adhesive. Highly efficient photovoltaic devices including electrodeposited cells of cadmium sulfide and cadmium telluride can be combined with evaporated and condensed cells of cadmium sulfide and copper indium diselenide can be manufactured according to the invention.

Multiple cell, two terminal photovoltaic device employing conductively

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

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.

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Hudson, OH, United States of America

William J Biter