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Photosensitive Sandwich Cells with Improved Photoresponse

IP.com Disclosure Number: IPCOM000082890D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Galli, G: AUTHOR

Abstract

Most photoconductive devices are made with electrodes on one surface of the photosensitive layer. There are many applications where it is desirable to have electrodes on opposite sides of the film. The following is a solution to the problem of obtaining such a device.

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Photosensitive Sandwich Cells with Improved Photoresponse

Most photoconductive devices are made with electrodes on one surface of the photosensitive layer. There are many applications where it is desirable to have electrodes on opposite sides of the film. The following is a solution to the problem of obtaining such a device.

A photoconductive "sintered" layer of CdSe was prepared. A mixture of 90% CdSe and 10% CdCl(2) with a quantity of CuCl(2) corresponding to 100 atom parts per million of cadmium was used. To the mixture a quantity of H(2)0 and glycerine was added as a vehicle for the slurry. The slurry was applied to a NESA coated glass substrate. The layer was then fired, in air, at 535 Degrees C for 30 minutes.

An indium sphere, 0.020" diameter was pressed to the CdSe surface. The electrical conductance of the cell was measured in the dark and in strong tungsten light, approximately 1 milliwatt/Cm . The ratio of light and dark conductances is considered to be a good figure of merit for photoconductors. As measured for this device, the Light/Dark = 27.

A silicone resin was then applied to the CdSe surface next to the indium dot. The liquid resin was seen to absorb into the porous layer producing a blacker spot. The color of the untreated material is grey. After the resin was cured (solid) the conductance measurements were repeated. A striking change in light/dark ratio was found. With the silicone impregnation the Light/Dark = 10/5/.

The light current was fou...