Abstract: An electronic solid state device comprising an inhomogeneous body in which grains of semiconductor material are present. The contact between adjoining grains is such that in the interface regions there is continuity between the bulk material of the adjoining grains and the dominant current conduction paths in the body lie within the grains via said grain to grain contacts. At the surfaces of the grains adjoining said interface regions rectifying barrier forming means are provided to enable control of the said current paths by surface field effect depletion in the interface regions. Said means can be opposite conductivity type surface layers at or on the grains. In other devices said means are formed by adsorbed gas atoms, ions or molecules. The said control may be employed to yield photoconductive layers with controllable gain and speed of response, said layers being used, for example, in solid state imaging devices.

Abstract: An electronic solid state device comprising a layer in which the electrical conductivity is controlled by a plurality of isolated discrete regions distributed within the bulk of the layer and forming potential barriers with semi conductor material of the layer surrounding the discrete regions. Electrical charge is stored in the layer by the discrete regions and the charging is obtained by the application of a potential pulse across the discrete regions. In a preferred operational mode the charging potential is applied such that current conduction paths in the layer are blocked by the depletion regions associated with the potential barrier for applied interrogation potentials across the regions of substantially smaller magnitude than the charging pulse. The device may consist of an imaging device having high charges gain and particular embodiments described consist of an image intensifier, an imaging active photocathode and a target plate of a vidicon camera tube.

Abstract: A semiconductor photocathode is described in which the electron emission is obtained from a P-type semiconductor into which free electrons are injected from the source or drain of an FET whose channel is normally blocked. Incident photons absorbed in the channel region unblock the FET causing electron emission. Preferably, the device comprises an imaging array of FET's and associated electron emitters.