Optical study on mesa structures with adjustable absorption based on Mn_1.56Co_0.96Ni_0.48O₄ thin films

In order to improve the infrared detection performance, mesa structures of Mn_1.56Co_0.96Ni_0.48O₄/Aluminum/Silicon dioxide/Silicon (MCN/Al/SiO₂/Si) were prepared by chemical solution deposition method. Raman spectroscopy results indicate that increasing the thickness causes a change in the Mn³⁺–O band stretching vibration and the Mn⁴⁺–O band bending vibration. Spectroscopic elllipsometry was used to obtain the dielectric function of the films by fitting the experiment data using the classical middle-infrared dispersion formula. The evaluated real part of the dielectric constants ε₁ and refractive index n decreased as the wavelength increase, the imaginary part ε₂ and extinction coefficient k monotonically increased as the wavelength increase in the entire measuring range of 2–10 μm. The calculated absorption spectra of the MCN/Al/SiO₂/Si structure showed that the absorption peak position could be adjusted by varying the thickness of the MCN films. Our results are important in the design and application of MCN film infrared detectors.