Innotech Corporation

Exxon Research and Engineering Company

Seymour Merrin

David A Krohn

James V Masi

Jack K Clifton

Richard L Anderson

A process is disclosed for making an optical fiber having a graded index glass core enveloped by a cladding material. The ingredients from which the peripheral part of the core glass is to be formed are placed in a closed tube of the cladding material which is more refractory than the core glass. The ingredients are melted to form a glassy liquid which is fined within the tube and then coated (for example, by rotational casting) on the inner surface of the tube. Additional ingredients, from which the inner part of the core glass is to be formed, are then placed in the coated tube, melted and similarly coated on the inner surface of the tube. In this way successive core glass layers, each having a different index of refraction, may be formed within the tube of cladding material. The temperature is then elevated further and the tube and glassy liquid drawn into a fiber.

Method of manufacturing graded index optical fibers

A glass electronic switching device having improved long-term reliability comprises a thin layer of an ion impermeable glass disposed between a pair of electrical contacts. Preferably the glass is an insulating glass having a thermal coefficient of expansion compatible with typical crystalline semiconductors, and the glass layer typically has a thickness of less than about five microns. These glass switches can be readily incorporated into high-density integrated circuits using planar techniques. When sufficiently thin glass layers are used, the same glass layer which comprises the active layer of the switching device can also comprise a masking layer to facilitate the fabrication of conventional diffused junction devices, a dielectric layer for the fabrication of surface effect devices, and a passivating layer to protect an underlying crystalline semiconductor substrate.

Glass switching device using an ion impermeable glass active layer

A semiconductive heterojunction device particularly useful as a photovoltaic device such as a solar cell comprises a heterojunction formed between a first layer of semiconductor material exhibiting one type of electronic conductivity (N or P) and a second layer of a compositionally different glassy amorphous material exhibiting the other type of electronic conductivity (P or N), which second layer has an energy bandgap relatively wider than that of the semiconductor material. Preferably, the wider bandgap glassy amorphous material possesses or is doped to possess a low resistivity below about 10.sup.7 ohm-cm.

Photovoltaic heterojunction device employing a glassy amorphous material

A semiconductive heterojunction device particularly useful as a photovoltaic device such as a solar cell comprises a heterojunction formed between a first layer of semiconductor material exhibiting one type of electronic conductivity (N or P) and a second layer of a compositionally different material exhibiting the other type of electronic conductivity (P or N), which second layer has an energy bandgap relatively wider than that of the semiconductor material and an electron affinity less than or equal to the electron affinity of the semiconductor. Preferably, the wider bandgap material is a glassy amorphous material which possess or is doped to possess a low resistivity below about 10.sup.7 ohm-cm. In devices employing N-type wider bandgap layers, the conduction band energy level of the wider bandgap material is preferably at substantially the same energy level as the conduction band energy level of the narrower bandgap material at electrical neutrality. In devices employing P-type wider bandgap layers, the valence band energy level of the wider bandgap material is preferably at substantially the same energy level as the valance band energy level of the narrower bandgap material.

Photovoltaic heterojunction device employing a wide bandgap material as

The conductivity of a body of ionically impermeable glassy amorphous material is controllably altered by driving or diffusing suitable impurities into the body of material. Impurities are driven into the glassy body by, for example, disposing a source of impurity ions on the surface and applying an electric field across the body. Preferably, the glassy amorphous material is heated so that its temperature is above a thermal diffusion temperature characteristic of the particular material and the particular impurity but is below the temperature at which an appreciable proportion of the impurities would be structurally incorporated into the material. Alternatively, impurities can be driven into a glassy body by ion bombardment. And in some material-impurity combinations, it is sufficient merely to heat the material above the thermal diffusion temperature in the presence of the dopant. The method provided by the invention can be used to render insulating glassy materials effectively semiconducting or to alter the conductive properties of glassy semiconductors. It can thus be used to produce a wide variety of bulk semiconductor devices such as switches as well as single junction and multiple junction semiconductor devices.

Growing community of inventors

Fairfield, CT, United States of America

Seymour Merrin