Abstract: Short-circuit current, maximum power, and open circuit voltage during a single flash are determined by varying intensity, voltage, and current. An apparatus determines the substrate doping and the series resistance of the solar cell. The series resistance of the cell is determined from a voltage step from the maximum power voltage operating point to the open-circuit condition. Methods are described for determining the substrate doping from stepping or sweeping the voltage. The first uses a voltage step and finds the change in charge that results. This determines a unique doping if the series resistance is known. The second uses data for a case of varying current, voltage, and light intensity, and compares this data to the case of varying voltage and intensity with no current. By transposing both cases into the steady state, agreement between the two data sets is found for unique doping and series resistance values.

Abstract: A solar cell or module is illuminated at one sun intensity and is placed into short circuit. Current and voltage measurements are taken. Control circuitry commands a second, higher terminal voltage of the solar cell such as a maximum power voltage. A higher intensity light pulse (for example, three suns) is applied to the solar cell or module when the second voltage is commanded. Voltage ramps more quickly because of the high-intensity light pulse. When the second terminal voltage is reached the light pulse terminates and measurements are taken while the solar cell remains illuminated at one sun intensity. The solar cell is placed into open circuit conditions and in conjunction with that action another high-intensity light pulse is applied. When the steady-state open circuit voltage for one sun is reached the pulse terminates. Characteristics are measured including current and voltage at the terminals of the solar cell or module.

Abstract: A solar cell or module is illuminated at one sun intensity and is placed into short circuit. Current and voltage measurements are taken. Control circuitry commands a second, higher terminal voltage of the solar cell such as a maximum power voltage. A higher intensity light pulse (for example, three suns) is applied to the solar cell or module when the second voltage is commanded. Voltage ramps more quickly because of the high-intensity light pulse. When the second terminal voltage is reached the light pulse terminates and measurements are taken while the solar cell remains illuminated at one sun intensity. The solar cell is placed into open circuit conditions and in conjunction with that action another high-intensity light pulse is applied. When the steady-state open circuit voltage for one sun is reached the pulse terminates. Characteristics are measured including current and voltage at the terminals of the solar cell or module.

Abstract: Short-circuit current, maximum power, and open circuit voltage during a single flash are determined by varying intensity, voltage, and current. An apparatus determines the substrate doping and the series resistance of the solar cell. The series resistance of the cell is determined from a voltage step from the maximum power voltage operating point to the open-circuit condition. Methods are described for determining the substrate doping from stepping or sweeping the voltage. The first uses a voltage step and finds the change in charge that results. This determines a unique doping if the series resistance is known. The second uses data for a case of varying current, voltage, and light intensity, and compares this data to the case of varying voltage and intensity with no current. By transposing both cases into the steady state, agreement between the two data sets is found for unique doping and series resistance values.

Abstract: A solar cell or solar module is measured during a short pulse of light in such a way that the resulting data for current and voltage at each light intensity is the same as would be measured under steady-state illumination conditions and therefore predictive of the actual performance of the solar cell or solar module in sunlight. A varying voltage is applied to the terminals of the solar cell during a light pulse so that the instantaneous current at a given voltage and light intensity during the light pulse is the same as would be measured under constant illumination at that same given intensity. A constant voltage is modified by a small signal correction that is proportional to the terminal current. Or, the small signal correction is proportional to the light intensity. An analog feedback circuit is constructed using the terminal current or light intensity for feedback in order to provide the requisite varying voltage. The varying voltage may also be supplied by digital synthesis.

Abstract: A solar cell or solar module is measured during a short pulse of light in such a way that the resulting data for current and voltage at each light intensity is the same as would be measured under steady-state illumination conditions and therefore predictive of the actual performance of the solar cell or solar module in sunlight. A varying voltage is applied to the terminals of the solar cell during a light pulse so that the instantaneous current at a given voltage and light intensity during the light pulse is the same as would be measured under constant illumination at that same given intensity. A constant voltage is modified by a small signal correction that is proportional to the terminal current. Or, the small signal correction is proportional to the light intensity. An analog feedback circuit is constructed using the terminal current or light intensity for feedback in order to provide the requisite varying voltage. The varying voltage may also be supplied by digital synthesis.

Abstract: A solar cell or solar module is measured during a short pulse of light in such a way that the resulting data for current and voltage at each light intensity is the same as would be measured under steady-state illumination conditions and therefore predictive of the actual performance of the solar cell or solar module in sunlight. A varying voltage is applied to the terminals of the solar cell during a light pulse so that the instantaneous current at a given voltage and light intensity during the light pulse is the same as would be measured under constant illumination at that same given intensity. A constant voltage is modified by a small signal correction that is proportional to the terminal current. Or, the small signal correction is proportional to the light intensity. An analog feedback circuit is constructed using the terminal current or light intensity for feedback in order to provide the requisite varying voltage. The varying voltage may also be supplied by digital synthesis.

Abstract: A solar cell or solar module is measured during a short pulse of light in such a way that the resulting data for current and voltage at each light intensity is the same as would be measured under steady-state illumination conditions and therefore predictive of the actual performance of the solar cell or solar module in sunlight. A varying voltage is applied to the terminals of the solar cell during a light pulse so that the instantaneous current at a given voltage and light intensity during the light pulse is the same as would be measured under constant illumination at that same given intensity. A constant voltage is modified by a small signal correction that is proportional to the terminal current. Or, the small signal correction is proportional to the light intensity. An analog feedback circuit is constructed using the terminal current or light intensity for feedback in order to provide the requisite varying voltage. The varying voltage may also be supplied by digital synthesis.

Abstract: A silicon solar cell has increased efficiency by providing an anti-reflection and passivation layer comprising a layer of silicon dioxide thermally grown on a surface of a silicon body and a layer of titanium dioxide deposited on the layer of silicon oxide. In fabricating the composite anti-reflection passivation layer, a layer of aluminum is first deposited on a surface of the thermally grown silicon oxide. After annealing the aluminum layer, the aluminum is removed from the silicon dioxide layer, and the layer of titanium dioxide is then deposited on the surface of the silicon dioxide from which the aluminum was removed. A layer of magnesium fluoride can be deposited on the surface of the titanium dioxide.

Abstract: Series connected cells of a solar array formed in a monolithic semiconductor substrate are electrically isolated by forming grooves in a first major surface partially through the substrate between cells and then fracturing the substrate from the bottom of the grooves to an opposing major surface. Metallization interconnecting the cells provides physical integrity of the cell array after the fracturing of the substrate. The grooves can be formed prior to completion of fabrication of the cells or after fabrication of the cells. In an array embodiment where each cell extends from one major surface to the opposing major surface, the grooves can be formed in both major surfaces.

Abstract: A high efficiency back side contact solar cell is fabricated using a self-aligning process that reduces the number of masks and alignments as compared with prior processes. The back surface of the cell is patterned by etching into an array of bilevel, interdigitated mesas and trenches, separated by inclined surfaces. Doping of the back surface region produces laterally alternating and overlapping P and N regions associated with the mesas and trenches. A metalization layer is deposited over the entire back side of the cell. The portions of the metalization on the inclined surfaces are readily removed by etching. Removal of the metalization on the inclines surfaces separates the mesa conductors from the trench conductors, leaving a well defined interdigitated array of positive electrodes and negative electrodes.

Abstract: A photovoltaic converter includes a photovoltaic cell and an enclosure around the cell with a reflective inner surface that reflects light to the cell. An aperture through the wall of the enclosure has a size smaller than the size of the photovaltaic cell. Light enters the enclosure through the aperture and falls upon the cell. Some light is reflected or not absorbed by the cell. This light is re-reflected back to the cell by the reflective inner surface of the enclosure. The small size of the aperture minimizes the escape of reflected light back out of the enclosure.