Method of manufacturing an infra-red detector device

In the manufacture of an infra-red detector device, at least a portion of a surface of a body of mercury cadmium telluride is subjected to a conversion treatment to produce a surface layer, after which a heating step is performed. The present invention involves a simple and reproducible process for forming in the body a p-n junction of sufficiently good quality for such a detector which can be of a planar form so as to facilitate the formation of the detector element arrays in the body and the provision of contacts to the detector elements