Open AccessBroadband control of the optical properties of semiconductors through site-controlled self-assembly of microcrystals
Author(s) -
Jacopo Pedrini,
Paolo Biagioni,
Andrea Ballabio,
Andrea Barzaghi,
Maura Bonzi,
Emiliano Bonera,
Giovanni Isella,
Fabio Pezzoli
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.398098
Subject(s) - materials science , silicon , photonic crystal , refractive index , optoelectronics , optics , absorption (acoustics) , photonics , band gap , broadband , semiconductor , physics , composite material
We investigate light-matter interactions in periodic silicon microcrystals fabricated combining top-down and bottom-up strategies. The morphology of the microcrystals, their periodic arrangement, and their high refractive index allow the exploration of photonic effects in microstructured architectures. We observe a notable decrease in reflectivity above the silicon bandgap from the ultraviolet to the near-infrared. Finite-difference time-domain simulations show that this phenomenon is accompanied by a ∼2-fold absorption enhancement with respect to a flat sample. Finally, we demonstrate that ordered silicon microstructures enable a fine tuning of the light absorption by changing experimentally accessible knobs as pattern and growth parameters. This work will facilitate the implementation of optoelectronic devices based on high-density microcrystals arrays with optimized light-matter interactions.