Doped photoconductive film including selenium and tellurium

摘要

A structure of a photoconductive film related to a target of an image pickup tube of the photo conductivity type is disclosed. This photoconductive film is formed from mainly Se and Te is added in a central part thereof. Further, As, which is considered to form a deep trap level which captures electrons in Se and GaF3, etc. which form negative space charges by capturing electrons in Se are added in the region adjacent to the region where Te exists. In addition, a thickness of film in the region where GaF3, etc. exists is selected to be thinner (not smaller than 20 ANGSTROM and not larger than 90 ANGSTROM ) than a value which has been adopted so far.