Abstract:
Despite recent advances in nonlinear optical techniques for examining elementary excitations in semiconductors, infrared spectroscopy remains an attractive
approach to nondestructive and quantitative measurement of relevant optoelectronic properties of materials, because of it is readily available as an experimental
technique and that relatively simple theories can be used to describe the material’s response to an infrared wavelength excitation. The optical and electronic
behavior of semiconductors are determined by two major properties particularly
energy gap and refractive index, the determination of which is necessary in the
design of optoelectronic devices. In this work, we use fourier-transform infrared
spectroscopy in reflective mode for the optical characterization of the manganese
oxide thin films synthesized on silicon substrates using Pulsed Laser Deposition,
under different experimental operating conditions, such as deposition temperature and pressure. The IR reflectivity measurements are analyzed by combining
the Kramers-Kronig conversion theorem with the Fresnel equations for the reflectivity of a multilayer structure. The technique used allowed to separate the
dielectric properties of the substrate from the dielectric properties of the thin
films. The results obtained show that the index of refraction of the films depends
on growth conditions and in some instances, high values of the index of refraction
in the infrared region can be obtained. This result paves the way for interesting
technological applications for these films as waveguides and other nanophotonic
devices.
