Transfer matrix method for calculating UV–Vis reflectivity/transmission spectra to assess thickness of nanostructured zb CdSe and ZnSe films grown on GaAs (001)

• Published in: Applied physics. A, Materials science & processing Vol. 129; no. 1
• Main Author: Talwar, Devki N.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2023; Springer Nature B.V
• Subjects: Applied physics; Characterization and Evaluation of Materials; Condensed Matter Physics; Interference fringes; Machines; Manufacturing; Materials science; Matrix methods; Multilayers; Nanostructure; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Reflectance; Spectra; Substrates; Surfaces and Interfaces; Thickness; Thin Films; Transfer matrices; Transfer matrix method; Multilayer optics; UV-Vis reflectivity/transmission spectra; Model dielectric function method; ZnCdSe ternary alloys
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-022-06267-5

Reflectivity analyses to estimate thickness for nanostructured epilayers by traditional methods is not feasible due to significant reductions of interference fringes in the transparent region. A classical approach based on the model dielectric functions is adopted here to simulate the optical constants of binary zb CdSe, ZnSe, GaAs (substrate) materials as well as ternary Zn x Cd 1− x Se alloys. The results of optical constants and film thicknesses are carefully integrated in the transfer matrix method (TMM) to acquire reflectivity spectra at near normal incidence θ i  = 0, for several ultrathin zb CdSe/GaAs (001) and ZnSe/GaAs (001) epilayers. Comparison of the simulated spectra with experimental data has offered accurate assessment of thicknesses for nanostructured zb CdSe/GaAs (001) and ZnSe/GaAs (001) epilayers. The TMM approach can easily be extended to examine the reflectivity and transmission spectra at oblique incidence ( θ i ≠ 0) in technologically important multilayer structures.