{211} polar surfaces of a Cd0.96Zn0.04Te chemically treated single crystal were investigated by Auger electron spectroscopy depth profiling. It was found that the use of a discriminatory “black‐white” etchant causes the formation of a thick layer with cadmium having been severely depleted at both (211) A and (211) B faces. The thickness of this layer is larger by a factor of 2 for the matt black face then for the bright and reflecting face. AES investigation of chemical treatment influence on (100) CdTe epitaxial layer surface has been performed. It has been established that etching in Br/methanol solution removes S, Cl and O containing contaminants from the surface, but simultaneously forms a Cd‐depleted layer.