Soft x-ray spectroscopic investigation of Zn doped CuCl produced by pulsed dc magnetron sputtering

• Published in: Journal of physics. Condensed matter Vol. 25; no. 28; p. 285501
• Main Authors: Rajani, K V, Daniels, S, McNally, P J, Krishnamurthy, S
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 17.07.2013; Institute of Physics
• Subjects: Adsorbed layers and thin films; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Doped films; Doping; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Magnetron sputtering; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Photoemission; Photoemission and photoelectron spectra; Physics; Surface layer; X-ray absorption and absorption edges; X-rays; Zinc; Soft X radiation; Impurity density; Zinc additions; Doping; VB calculations; Hall effect; EXAFS; Thin films; Cathode sputtering; Ultraviolet radiation; Electronic structure; Binding energy; Copper chloride; X-ray photoelectron spectra
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/25/28/285501

We report on a systematic investigation of the electronic properties of UV-light emitting Zn doped CuCl thin films implemented using near edge x-ray absorption fine structures (NEXAFS) and high-resolution x-ray photoemission spectroscopy. A clear shift of the valence band maximum towards higher binding energy by 0.2 ± 0.1 eV was observed in Zn doped CuCl as compared to undoped CuCl. This shift is in correlation with the increase in conductivity measured by the Hall effect measurements. A decrease in the optical band gap of CuCl film is also observed as a function of Zn doping. The profound changes in the full width at half maximum and the gradual disappearance of satellite features of Cu 2p core level photoemission as a function of Zn dopant are attributed to the reduced presence of the surface layer of Cu2+ species with d9 configuration in the doped films. These investigations help us to understand the doping mechanisms and underlying physics. The reduced presence of the Cu2+ related surface layer as a function of Zn doping is also verified using NEXAFS.