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: Switch means having a predetermined number of switch positions normally applies any selected one of the same predetermined number of separate control signals to a galvanometer in accordance with the switch position to which the switch means is operated. However, in response to each operation of the switch means between switch positions, a reference signal is applied to the galvanometer for a given time. This overcomes the degrading effect of hysteresis on galvanometer accuracy.

Abstract: A method of inducing differential etch rates in glow discharge produced amorphous silicon by heating a portion of the glow discharge produced amorphous silicon to a temperature of about 365.degree. C. higher than the deposition temperature prior to etching. The etch rate of the exposed amorphous silicon is less than the unheated amorphous silicon.

Abstract: A laser beam apparatus and method for analyzing, inter alia, the current versus voltage curve at the point of illumination on a solar cell and the open circuit voltage of a solar cell. The apparatus incorporates a lock-in amplifier, and a laser beam light chopper which permits the measurement of the AC current of the solar cell at an applied DC voltage at the position on the solar cell where the cell is illuminated and a feedback scheme which permits the direct scanning measurements of the open circuit voltage. The accuracy of the measurement is a function of the intensity and wavelength of the laser light with respect to the intensity and wavelength distribution of sunlight and the percentage the dark current is at the open circuit voltage to the short circuit current of the solar cell.

Abstract: Amorphous silicon layers deposited on a suitable substrate in a glow discharge of silane or other silicon containing compounds are sensitive optical storage media.