Strong Photoluminescence Enhancement in All‐Dielectric Ge Thin Film Metasurfaces for Integration on the Si Platform

ABSTRACT In this work, we demonstrate how germanium (Ge) all‐dielectric metasurfaces can be leveraged to strongly enhance the radiative emission from Ge layers grown on silicon‐on‐insulator substrates by industry‐standard processes. At room‐temperature, the narrowband photoluminescence (PL) intensity is enhanced by a factor of ∼40× with respect to unstructured films. Power dependence analysis of the PL confirms direct band‐to‐band recombination as the dominant mechanism. According to full‐wave simulation results, the emitted spectral intensity is well described by multipole modes of coupled Mie resonators, and can be tailored with respect to wavelength, polarization, and directivity by a suitable nanostructuring of the metasurface. This tunability‐by‐design, as well as the use of industry‐standard processes and materials, bode well for the adoption within silicon electronic‐photonic integrated circuit technologies for different applications, e.g., in local interconnects or photonic computing hardware.