| 摘要 |
<p>727,949. Plate rectifiers. SIEMENSSCHUCKERTWERKE AKT.-GES. May 28, 1953 [June 19, 1952], No. 14934/53. Class 37. A selenium rectifier has the selenium layer produced by evaporating selenium simultaneously with an additional substance which has its vapour pressure maintained below 10<SP>-2</SP> mm. Hg, the substance influencing the crystallization of the selenium layer so that the internal region crystallizes faster than the surface zone. The added substance may be a liquid such as a mineral oil, tricresyl phosphate or chlorinated divinyl, or a semi-solid such as fat, wax or paraffin, or a solid such as sulphur, tellurium or carbon, which promote crystallization and are therefore applied only while the internal region is being formed. Alternatively, substances such as phosphorus, arsenic or antimony, which inhibit crystallization may be applied only while the surface region is being formed. Combinations or mixtures of these substances may be employed. The process can be carried out by having a vacuum chamber containing one evaporation vessel for the selenium and one for the additional substance with separate thermocouples and temperature controls. The vessel containing the substance may have a mechanical shutter. The materials are evaporated on to a heated base-plate in the chamber. The crystallization of the selenium layer may be effected by heat treatment after the application of the materials by evaporation. A tin-cadmium or tin-cadmium-bismuth counter electrode may be applied after crystallization, and heat treatment at 210‹ C. applied to provide a barrier layer between the selenium and the counter electrode. Electrical forming treatment may then be applied.</p> |
