for example in a photovoltaic cell the method comprises forming a te rich layer on the surface of the cd and te containing compound film depositing an interface layer on the te rich layer and laying down a contact layer on the interface layer the interface layer is composed of a metallic form of zn and cu application_number US 88067110 A description fig2 shows the processing steps used to form an ohmic contact to a cdte film in accordance with embodiments of the present invention it should be noted that the method described herein is specifically suited for making ohmic contact to p type cdte material which is commonly used in solar cell fabrication as can be seen from fig2 the first step of the process is to form a thin te rich layer on the surface of the cdte film the te rich layer can be obtained by various means such as by depositing te on the surface of the cdte film using physical vapor deposition techniques such as evaporation or sublimation and sputtering by chemical vapor deposition cvd techniques or by chemically etching the surface of the cdte film by an acidic etch solution it is well known that acidic solutions which may comprise at least one acid such as phosphoric acid forming acid sulfuric acid bromine solution chromic acid nitric acid etc preferentially etch the cd at the cdte surface leaving behind a te rich layer i e a layer within which the te cd molar ratio is larger than 1 0 the second step of the process involves deposition of an interface layer on the te rich layer wherein the interface layer comprises.