Study of the Composition of Uncontrolled Impurities and the Profiles of Their Distribution at the Ni–CdS Interface

The atomic concentration of uncontrolled impurities, their chemical composition on the surface of Ni films, as well as the distribution profiles of atoms of some impurities in Ni films and at the interface of the Ni–CdS system are investigated using Auger-electron spectroscopy and secondary-ion mass spectrometry. Ni films with a thickness of 0.5–1 μm are obtained by thermal evaporation in vacuum (~10 –6 Pa). In a well degassed Ni film, in addition to oxygen and carbon, impurity atoms of more than 10 elements are found, but their total concentration is only ~1–1.5 at %. These impurity atoms penetrate the Ni–CdS interface and their penetration depth into the Ni layer is 0.3–0.4 µm. At the interface of the Ni–CdS system, the oxygen concentration reaches 8–10 at %, resulting in the formation of NiO- and NiO 2 -type compounds.