(US4828628-A)      Solar cell (10) of semiconductor material such as Si comprises a p-doped Si substrate (1), a thin Si oxide layer (2), ohmic contacts 4) on the Si body and a metal insulator semiconductor contact composed of the substrate, oxide later and a metallised layer (3), pref. of Al or Mg. Incident light generates electrons and holes in the substrate, electrons being drawn by the electric field of the metal insulator semiconductor contact and are drawn into the metal, while holes diffuse towards the front and leave the Si via an ohmic contact (4), forming a geometric pattern, with passivation layers in between, the first passivation layer (5) being an anti-reflection layer.    ADVANTAGE -   Simplification and cost redn. makes large-scale prodn. of large area cells possible. (11pp)n    (US4900369-A)      Solar cell comprises (a) a substrate layer of semiconductor material of a first conductivity type, in which energy from a radiation source generates minority and majority charge carriers, layer (a) having a first surface facing the front of the cell and a second surface facing the rear of the cell; (b) a highly doped semiconductor layer of second conductivity type formed on the first surface of (a), the second conductivity type being opposite to that of the first conductivity type; (c) a plurality of spaced first ohmic contacts formed on (b); (d) a plurality of spaced second ohmic contacts formed directly on the second surface of (a); and (e) an insulation, passivation and antireflection layer formed over and between the second ohmic contacts. Layer (b) forms junction means for providing an electrical field for sepg. the minority and majority charge carriers in the region of the first surface of (a) so that the majority charge carriers diffuse to the second ohmic contacts and are collected by them. The thickness of (a) is less than or equal to the diffusion length of the minority charge carriers in (a).    ADVANTAGE -   The recombination velocity in the area of the ohmic contact is considerably reduced without the usual provision of a potential barrier for minority charge carriers, with consequent simplification and cost redn. of the manufacturing process. (11pp)