¹Mykola Gogol State University of Nizhyn, 2, Hrafska str., 16600 Nizhyn, Ukraine
²V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 45, prosp. Nauky, 03680 Kyiv, Ukraine
³Institute of Physics of National Academy of Sciences of Ukraine, 46, prosp. Nauky, 03680 Kyiv, Ukraine
⁴National university “Kyiv Mohyla Academy”, 2, Skovorody str., 04070 Kyiv, Ukraine
E-mail: mov310310@gmail.com*; khomen@ukr.net**

Abstract. Undoped and Mn-doped ZnO ceramics were theoretically and experimentally investigated using specular infrared reflection method. It was shown that infrared reflection spectra can be modeled using the parameters explored for ZnO single crystals. For ceramic samples, it was shown that ZnO grains with orientation of the C-axis along the normal to the electric field ( ) give the main contribution to IR reflection spectra. It has been ascertained that the surface roughness is manifested in these spectra mainly within the range 450…550 cm–1 giving negligible effect for the frequencies above longitudinal phonon frequency. This allowed the electrophysical parameters of ZnO crystallites to be evaluated. In the case of undoped ceramics, the obtained results were found to be consistent with the values of direct current measurements. This finding supports the utility of infrared spectroscopy for determination of the electrophysical parameters of polycrystalline ceramic materials. For Mn-doped ceramic samples, the conductivity value measured using the direct current method was found to be essentially lower than those determined from simulation of infrared reflection spectra. This phenomenon was explained by barrier formation at the grain boundaries in Mn-doped ZnO ceramics.

Keywords:ZnO, ceramics, infrared spectroscopy, doping, conductivity.

Full Text (PDF)

References

Back to Volume 24 N4