Spectroscopic imaging ellipsometry of two-dimensional TMDC heterostructures

Semiconducting two-dimensional materials and their heterostructures gained a lot of interest for applications as well fundamental studies due to rich optical properties. Assembly in van der Waals heterostacks can significantly alter the intrinsic properties wavelength-dependent absorption emission efficiencies, making direct comparison of, e.g., photoluminescence intensities difficult. Here, we determine dielectric function prototypical MoSe 2 /WSe heterobilayer individual layers. Apart from redshift 18–44 meV energetically lowest interband transitions, find that larger energies, only be described by treating new artificial homobilayer crystal rather than stack The determined functions are applied calculate Michelson contrast layers bilayer dependence oxide thickness often used Si/SiO substrates. Our results highlight need consider altered impacting interference interpretation measurements such Raman scattering or photoluminescence.