Fabrication of spectrally sharp Si-based dielectric resonators: combining etaloning with Mie resonances

Abstract

We use low-resolution optical lithography joined with solid state dewetting of crystalline, ultra-thin silicon on insulator (c-UT-SOI) to form monocrystalline, atomically smooth, silicon-based Mie resonators in well-controlled large periodic arrays. The dewetted islands have a typical size in the 100 nm range, about one order of magnitude smaller than the etching resolution. Exploiting a 2 µm thick SiO2 layer separating the islands and the underlying bulk silicon wafer, we combine the resonant modes of the antennas with the etalon effect. This approach sets the resonance spectral position and improves the structural colorization and the contrast between scattering maxima and minima of individual resonant antennas. Our results demonstrate that templated dewetting enables the formation of defect-free, faceted islands that are much smaller than the nominal etching resolution and that an appropriate engineering of the substrate improves their scattering properties. These results are relevant to applications in spectral filtering, structural color and beam steering with all-dielectric photonic devices.

Light Emitting Si‐Based Mie Resonators: Toward a Huygens Source of Quantum Emitters

“…For an extensive characterization of SEM images of a similar sample obtained in the same dewetting conditions we refer the reader to ref. [42]. These islands are monocrystalline and atomically smooth, featuring the typical facets of the equilibrium shape of silicon (113, 111, and 001), as highlighted on the atomic force microscope (AFM) height profile shown in Figure 1c.…”

“…For an extensive SEM characterization of similar samples, obtained with the same method, see ref. [42]. c) Height profile of a Si island from the array shown in (b) obtained from an atomic force microscope image.…”

“…Fabrication of Si resonant antennas via dewetting [ 39–41,43 ] and the characterization of their optical properties under white light illumination have been extensively addressed in the past few years, and we thus refer the reader to the existing literature. [ 42,44 ] The nano‐fabrication was performed following these steps (Figure 1): 1)Starting from a 125 nm thick silicon on insulator wafer (UT‐SOI) atop 2 µm buried oxide (BOX), we progressively thinned the UT‐SOI via thermal oxidation in a rapid thermal processor leaving at the end of the process a 20 nm Si layer atop the BOX. The thermal oxide formed on the UT‐SOI was removed via chemical etching in HF solution. 2)By patterning the UT‐SOI via low‐resolution (≈2 µm) photolithography and plasma etching, we formed µm sized, UT‐SOI patches (Figure 1a, top panel).…”

Quantum Confined Stark Effect on the Linear and Nonlinear Optical Properties of SiGe/Si Semi Oblate and Prolate Quantum Dots Grown in Si Wetting Layer

“…They are considered the most realistic models that are close to the experimental samples. The semiconducting material Si 1−η Ge η , (where η is the concentration of Ge) has been used for many electronic devices due to its large density, high dielectric constant and excellent optical properties [49][50][51][52][53]. Their nonlinear optical properties like AC, RIC, second harmonic generation (SHG) and third harmonic generation (THG) provide a thorough insight into the mechanism of the optical response.…”

Tailoring Third-Harmonic Diffraction Efficiency by Hybrid Modes in High-Q Metasurfaces

“…The use of materials with large nonlinear susceptibilities expands the operation scope of metasurfaces to the nonlinear signals. The employment of materials with a high-refractive index for metasurfaces further boosts the nonlinear-optical effects in visible and near-IR ranges due to the strong local field enhancement inside the nanoresonators. − Moreover, metasurfaces allow one to control the nonlinear wavefront − and, in particular, the nonlinear diffraction − through size, shape, and orientation engineering of meta-atoms even in the absence of phase matching.…”