A method of producing a uniform layer of pure thallium sulphide on the selenium layer of rectifier plates

摘要

1,038,194. Selenium rectifiers. LICENTIA PATENT-VERWALTUNGS-G.m.b.H. April 11, 1963 [April 13, 1962; June 8, 1962], No. 14551/63. Heading H1K. In the manufacture of selenium rectifiers a solution containing a thallium compound is applied to a selenium layer on a base plate and treated with hydrogen sulphide to deposit thallium sulphide. In a preferred method a solution of thallium ethoxide in an anhydrous alcohol is sprayed on the selenium and then placed in an atmosphere of hydrogen sulphide for an hour. Alternatively a solution, e.g. of thioacetamide in alcohol, which decomposes on heating to produce only hydrogen sulphide and volatile products is mixed with the ethoxide solution or is sprayed on with, before, or after it. The resulting assembly is then heated to 100‹ C. for 5 minutes after which a counter-electrode is applied and the device formed.