Light emission features in ionization-type semiconductor photographic system

Abstract

Light emission in the UV and visible (blue) range (330–440 nm) generated by the cell of a semiconductor photographic system and the possibility of locally increasing the gasdischarge light emission for a given photosensitivity of a planar GaAs photodetector is studied. The use of metallic patched concentrators with an area S = 5 × 10−4 cm2 and density 400 cm−2 and an IR light to excite the photocathode of the system leads to a fivefold increase in the gas discharge light intensity. In a system with metallic patched concentrators, the local density of gas-discharge light exceeds the density of uniform gas-discharge light in a semiconductor photographic system by the same factor as the working area of the photocathode exceeds the total area of the current concentrators. Moreover, the use of current concentrators with a double metallic layer prolongs only the working time of the photodetector, and it does not create additional limitations on the resolution of the photodetector. Filamentation was primarily due to the formation of a space charge of positive ions in the discharge gap, which changed the discharge from the Townsend to the glow type. These characteristics of the system can be applied to high-speed photography and registration of ir images.