Abstract: An optical reading device with the least cross-talk and good reading resolution, which is constructed with a plurality of metal electrodes disposed on an insulating base plate in a spaced apart relationship for each bit, a photoconductive film provided on the plurality of metal electrodes, and a transparent electrically conductive film disposed in confrontation to the plurality of metal electrodes, wherein the photoconductive film possesses high resistance value at least at the side thereof facing the metal electrode, the transparent electrically conductive film and the photoconductive film are cut out at their portions corresponding to a positional space between adjacent metal electrodes, and the photoconductive film does not substantially protrude from the transparent electrically conductive film at a portion where the transparent electrically conductive film confronts to each of the metal electrodes.

Abstract: This invention relates to a method for growing semi-insulating III-V compound semiconductor crystals on a substrate by means of an epitaxially crystallizing process in the liquid state, which comprises the steps of:A. placing a saturated solution of a III-V compound in a reaction tube,B. carrying out a heating of the solution in the atmosphere of H.sub.2 gas, andC. growing a crystal of the III-V compound on the substrate in the liquid phase at a temperature below the melting point of the III-V compound while keeping the vapor pressure of the V Group element under a predetermined value in the reaction tube.