Short communication: Effects of heat treatments and CdCl 2 , pretreatments on the stoichiometries of solution‐grown CdS thin films

Solution grorwth of CdS on SnO 2 ‐coated glass with subsequent heat treatments is known to produce stoichiometric CdS thin films with characteristic thicknesses of about 1000 Å. We show that heating solution‐grown CdS thin films in a nitrogen atmosphere to ⩾ 450° C results in sulphur loss. Heating to 550°C leads to a 50% loss of sulphur, leaving the entire 1000‐A CdS thin film with a concentration of about 75 at.% Cd and 25 at.% S. However, dipping the CdS thin films in a CdCl 2 solution prior to heating coats the CdS, leaving a CdCl 2 layer that acts as a protective coating and prohibits the loss of sulphur. Cadmium sulphide thin films dipped in a CdCl 2 solution and then heated to 550°C are stoichiometric.