Abstract: A method is provided for accelerating and improving the recovery of GaAs solar cells from the damage which they experience in space under high energy particle irradiation such as electrons, protons and neutrons. The method comprises combining thermal annealing with injection annealing. Injection annealing is the recovery from radiation damage resulting from minority carrier injection into the damaged semiconductor, nonradiative minority carrier combination of the injected minority carriers, transfer of the recombination energy to the crystal lattice and utilization of this energy to remove the defects caused by the high energy particle irradiation. The combined annealing of this invention is implemented by heating the solar cells to a moderate temperature (on the order of about 200.degree. C. to 300.degree. C.

Abstract: An apparatus including a white light and first, second, and third filters through which the white light is transmitted is utilized to sequentially irradiate a solar cell. The light impinging upon the solar cell from the first, second, and third filters has first, second, and third "tristimulus" distributions. The resulting first, second, and third electrical output quantities produced by the solar cell are measured and utilized to compute normalized spectral response coefficients by normalizing each of the electrical output quantities with respect to the sum of the three. First, second, and third response differences are obtained by subtracting the first, second, and third response coefficients from first, second and third response coefficients previously obtained from a reference solar cell.

Abstract: Systems and methods for detecting and eliminating latent and existing short circuit current paths through photovoltaic devices of the type including at least one semiconductor region overlying a substrate and a layer of conductive light transmissive material overlying the at least one semiconductor region are disclosed. The latent paths are first converted to existing short circuit current paths by applying a bias voltage to the devices. The short circuit current paths which are eliminated extend through the at least one semiconductor region from the substrate to the layer of conductive light transmissive material. The resistivity of the short circuit current paths is increased substantially at the interface between the conductive light transmissive material and the semiconductor region by isolating electrically the conductive light transmissive material from the short circuit current path.

Abstract: A laboratory testing mechanism for determining conformance of an optical iation detector to prespecified time response requirements, comprising an electrically-operated shutter and a fast-moving rotary disc located between a radiation source and the detector under testing. Proximity switch associated with the disc provide electrical signals representing the time at which the window of the detector is initially exposed to the radiation source and selected elapsed time intervals thereafter.

Abstract: A method of electrically isolating portions of a large surface area semiconductor body for various purposes such as the production of improved photovoltaic and semiconductor devices is disclosed herein. In the preferred embodiment, the photovoltaic devices are of the type which include a common, electrically conductive substrate layer, a semiconductor body deposited upon the substrate layer, and a transparent electrically conductive coating layer is deposited atop the amorphous body.

Abstract: The present invention relates to a method for removing electrical shorts and shunts from solar cells, such as amorphous silicon solar cells. The method involves back-biasing the solar cells while they are in an electrolytic solution. It has been found that the process results in the removal of the shorts and shunts present in the cell.

Abstract: Amorphous silicon solar cells have been shown to have efficiencies which degrade as a result of long exposure to light. Annealing such cells in air at a temperature of about 200.degree. C. for at least 30 minutes restores their efficiency.

Abstract: A process for fabricating solar to electrical energy conversion units, includes the forming of arrays of parallel-connected strings of series connected solar cells selected from a number of different categories of cells. The categories are defined by different ranges of cell currents at a set cell voltage, a set level of incident cell face radiation and a set temperature. Each string of an array consists of cells from the same category; but strings of cells from different categories are used in the same array. A goal array current range for the arrays may be correlated with the average current of a group of cells at the set conditions, or with the estimated average for a group of cells to be manufactured, so that a selected number of strings for the arrays multiplied by such average falls within the range. According to a particular fabricating process, nine solar cell categories covering a total of approximately 0.

Abstract: Efficiency of silicon solar cells containing about 10.sup.15 atoms/cm.sup.3 of chromium is improved about 26% by thermal annealing of the silicon wafer at a temperature of 200.degree. C. to form chromium precipitates having a diameter of less than 1 Angstrom. Further improvement in efficiency is achieved by scribing laser lines onto the back surface of the wafer at a spacing of at least 0.5 mm and at a depth of less than 13 micrometers to preferentially precipitate chromium near the back surface and away from the junction region of the device. This provides an economical way to improve the deleterious effects of chromium, one of the impurities present in metallurgical grade silicon material.