Thermal conversion of Cu4O3 into CuO and Cu2O and the electrical properties of magnetron sputtered Cu4O3 thin films
- 179 Downloads
Among the three oxides of copper (CuO, Cu2O, and Cu4O3), Cu4O3 phase (paramelaconite is a natural, and very scarce mineral) is very difficult to synthesize. It contains copper in both + 1 and + 2 valence states, with an average composition Cu21+Cu22+O3. We have successfully synthesized Cu4O3 phase at room temperature (300 K) by reactive DC magnetron sputtering by controlling the oxygen flow rate (Murali and Subrahmanyam in J Phys D Appl Phys 49:375102, 2016). In the present communication, Cu4O3 thin films are converted to CuO phases by annealing in the air at 680 K and to Cu2O phase when annealed in argon at 720 K; these phase changes are confirmed by temperature-dependent Raman spectroscopy studies. Probably, this is the first report of the conversion of Cu4O3–CuO and Cu2O by thermal annealing. The temperature-dependent (300–200 K) electrical transport properties of Cu4O3 thin films show that the charge transport above 190 K follows Arrhenius-type behavior with activation energy of 0.14 eV. From photo-electron spectroscopy and electrical transport measurements of Cu4O3 thin films, a downward band bending is observed at the surface of the thin film, which shows its p-type semiconducting nature. The successful preparation of phase pure p-type semiconducting Cu4O3 could provide opportunities to further explore its potential applications.
- 5.A.S. Zoolfakar, R.A. Rani, A.J. Morfa, A.P. O’Mullane, K. Kalantar-Zadeh, Nanostructured copper oxide semiconductors: a perspective on materials, synthesis methods and applications. J. Mater. Chem. 2, 5247–5270 (2014)Google Scholar
- 13.A.Y. Anderson, Y. Bouhadana, H.-N. Barad, B. Kupfer, E. Rosh-Hodesh, H. Aviv, Y.R. Tischler, S. Rühle, A. Zaban, Quantum efficiency and bandgap analysis for combinatorial photovoltaics: sorting activity of Cu–O compounds in all-oxide device libraries. ACS Comb. Sci. 16, 53–65 (2014)CrossRefGoogle Scholar
- 15.J.I. Pankove, Optical Processes in Semiconductors (Dover, New York, 1971)Google Scholar