Infrared optical properties of Mn_(1.56)Co_(0.96)Ni_(0.48)O_4 thin films prepared by chemical solution deposition

摘要

～2 urn thick Mn_(1.56)Co_(0.96)Ni_(0.48)_O_4 (MCN) films have been prepared on a AI2O3 substrate by the chemical solution deposition method. X-ray diffraction and microstruc-ture analyses show good crystallization and the thickness of the films is 2.12 (am. Mid-infrared optical properties of MCN films have been investigated using transmission spectra and infrared spectroscopic ellipsometry. The optical band gap of the MCN film has been derived to be 0.64 eV by assuming a direct transition between valence and conduction bands. The optical constants and thickness of the thin films have been obtained by fitting the measured ellipsometric parameter data with the classical infrared model. The refractive index n of the MCN films decreases as the wavelength increases, but the extinction coefficient k monotonously increases in the wavelength range of 2-7 μm. The maximal n value is 2.63, and the maximal k value is only 0.024. The above results are instructive for the applications of MCN films in infrared detecting.