Abstract: The disclosed thyristor comprises an n.sup.- semi-conductor layer, a p.sup.- semiconductor layer disposed on one surface of the n.sup.- layer to form a pn junction between them, an n.sup.+ and a p.sup.+ semiconductor layer disposed on the other surfaces of the n.sup.- and p.sup.- layers respectively to serve as main electrodes and a p.sup.+ and a n.sup.+ apertured gate layers disposed within the n.sup.- and p.sup.- layers respectively and provided with a gate electrode. An intrinsic semiconductor layer may be substituted for the n.sup.- and p.sup.- layers. A process of producing such a thyristor is also disclosed.

Abstract: A luminosity control device comprises a first semiconductor laser operable in a spontaneous mode to emit noncoherent light and in a laser mode different from its inherent laser mode to emit coherent light. The first semiconductor laser is electrically biased into its spontaneous laser mode. A second semiconductor laser is operated in a laser mode to emit coherent light which is applied to the first semiconductor laser to optically bias the first semiconductor laser into the laser mode of the second semiconductor laser. The second semiconductor laser is electrically biased into operating in its laser mode and the optical coupling between the two semiconductor lasers is such that the coherent light output from the first semiconductor laser varies exponentially with respect to the electrical energy input into the second semiconductor laser.

Abstract: A spinel single crystal substrate for epitaxial growth thereon of a semiconductor layer to manufacture semiconductor devices. Magnesium titanate is substituted for at least a portion of magnesium aluminate of which the spinel essentially consist in general. A preferred mol ratio of the magnesium titanate to the magnesium aluminate is between 5:95 and 40:60 when a silicon layer is to be epitaxially grown on the substrate as the semiconductor layer.

Abstract: A single crystal of gallium phosphide including 0.5 atomic ratio or less of indium is grown from a melt consisting of indium, gallium and phosphorous with an atomic ratio of gallium to phosphorous equal to at least 2.0.

Abstract: Signal collecting and distributing systems wherein an active transmission line possessing neuristor characteristics is provided as a means for scanning a plurality of signal transducers, which may be in the form of radiation sensitive elements or electroluminescent elements, respectively, to effect actuation thereof in a prescribed order.