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 highly sensitive broad band mass spectrometer consists of a broad band selector of a low energy level beam of negative ions to be examined; a molecular disintegrator and charge changer which receives the negative ions and produces a beam of high-energy multiply charged positive ions free of molecules; and a broad band high-energy, continuously-operable isochronous time-of-flight mass spectrometer which receives the output from the molecular disintegrator. The disintegrator destroys molecules that would obscure the measurement of atomic species. Both selector and spectrometer preferably are electrostatic to avoid mass discrimination and maintain the broad band capability. The use of an isochronous time-of-flight mass spectrometer permits continuous operation which increases sensitivity. The ion selector may be of a magnetic type if a somewhat narrower band of masses is acceptable.