Abstract: The present invention provides a thin film amorphous silicon-crystalline silicon back heterojunction and back surface field device configuration for a heterojunction solar cell. The configuration is attained by the formation of heterojunctions on the back surface of crystalline silicon at low temperatures. Low temperature fabrication allows for the application of low resolution lithography and/or shadow masking processes to produce the structures. The heterojunctions and interface passivation can be formed through a variety of material compositions and deposition processes, including appropriate surface restructing techniques. The configuration achieves separation of optimization requirements for light absorption and carrier generation at the front surface on which the light is incident, and in the bulk, and charge carrier collection at the back of the device. The shadowing losses are eliminated by positioning the electrical contacts at the back thereby removing them from the path of the incident light.

Abstract: A nuclear battery is provided by the incorporation through chemical bonding of radioactive tritium in a body of amorphous semiconductor material having a p-type conductivity region, an n-type conductivity region and a semiconductor junction therebetween, with means for electrically connecting the n-type and p-type regions to a load circuit. A preferred such nuclear battery comprises tritium chemically bonded within an amorphous silicon semiconductor including a p-i-n junction.

Abstract: A radioluminescent source is provided by a radioactive element entrapped in an amorphous semiconductor. A preferred light source comprises a beta-emitting radioactive element, such as tritium, occluded within a matrix of amorphous semiconductor material, such as amorphous silicon, with or without dopants. The matrix may serve as an intrinsic radioluminescent light source, or as an electron source to irradiate a separate phosphor.

Abstract: The invention provides new methods and apparatus for the deposition of materials on substrates by the use of a D.C. glow discharge, sometimes also called a plasma discharge. A precursor gas (or gases) is introduced at low pressure (10-500 milliTor) into an enclosure containing two spaced parallel cathode electrodes and an intermediate parallel anode electrode, preferably midway between the two cathodes, which anode electrode is permeable to at least electrons of the glow or plasma discharge. Upon application of a suitable positive potential to the anode a deposition plasma is generated in the space on both sides of the anode.

Abstract: Silicon-based solar cells devised hitherto have used crystalline silicon because of its acceptable electrical characteristics. Amorphous silicon is much cheaper and has better optical absorption characteristics, but its electrical characteristics are so poor that it cannot be used, without some additional treatment such as hydrogenation. The invention provides a method of production of solar cells using amorphous silicon in which the silicon is evaporated in a suitable vacuum onto a substrate in the presence of a positive field which opposes the migration of the positive silicon ions toward the substrate. The resulting devices are found to have much improved electrical characteristics while retaining a good absorption characteristic. A tentative hypothesis is given for the unexpected improvement.

Abstract: A new silicon based semiconductor device comprises a layer of amorphous silicon in which the density of energy states in the energy gap has been reduced by hydrogenation; this layer is deposited on a layer of a hydrogen-containing substrate material that can supply hydrogen in atomic form to the amorphous silicon. In processes of the invention the silicon layer and a substrate layer are hydrogenated separately to permit optimum hydrogenation; the silicon layer may be deposited without hydrogenation and hydrogenated subsequently with hydrogen from the substrate material. A specific example consists of a layer of hydrogenated amorphous silicon of about 1 micrometer thickness deposited on a hydrogen-containing chromium layer which is itself deposited on a carrier, the silicon then forming the active element of a photovoltaic cell particularly functional as a solar cell.