Modeling of Sputtered Mo-Al2O3 Nanocomposites Using a Combination of FDTD Method and Maxwell Garnett Approximation

In this study, Mo-Al
2
O
3
nano composites (NCs) films with different thicknesses and nominal metal volume fractions (f) were grown on polished glass substrates, using sequential DC and RF sputtering. The reflectance (R) and transmittance (T) curves of the NCs were measured in the spectral range of 300 nm and 1700 nm. The measured R and T characteristics of NCs were compared with the numerical FDTD models. Two approaches were used: (1) Individual Mo nanoparticles with proper size and distribution (bcc lattice) were modelled. (2) NCs layers were modelled as homogeneous thin films with optical constants (real and imaginary parts of the complex index of refraction) obtained through Maxwell Garnett effective medium approximation. In both cases, optical constants of pure bulk Mo and sputtered Mo were used, and the results were compared.