8:15 - 9:00Special InvitedID: 348
/ TOM6 S01: 1
TOM 6 Optical Materials: crystals, thin films, organic molecules and polymers, syntheses, characterization and devices
Nanomaterials for light-driven multi-electron processes
Ilka Kriegel
Italian Institute of Technology, Italy
The photodoping of highly doped metal oxide nanocrystals results in the accumulation of multiple electrons. Electron counting via titration indicates that multi-charge transfer processes are involved and that hundreds of electrons are stored per nanounit. This corresponds to capacitance values that are comparable to commercially available supercapacitor materials. In this presentation, I will discuss the fundamental physical and chemical processes underlying photodoping. I will further discuss open questions with regards to their implementation as novel light-driven multi-charge accumulation components in the next generation of solar energy devices.
9:00 - 9:15ID: 142
/ TOM6 S01: 2
TOM 6 Optical Materials: crystals, thin films, organic molecules and polymers, syntheses, characterization and devices
GaAs/AlGaAs coreshell wires light emitters on dewetted SiGe Mie resonators
Luca Fagiani1,2, Chiara Barri1,2, Mohammed Bouabdellaoui3, Erfan Mafakheri2, Nicoletta Granchi4, Michele Montanari4, Andrea Ristori4, Francesco Biccari4, Alexey Fedorov2, Stefano Sanguinetti5, Massimo Gurioli4, Marco Abbarchi3, Monica Bollani2
1Department of Physics, Politecnico di Milano, Milano, 20133, Italy; 2L-NESS, IFN-CNR, Como, 22100, Italy; 3Aix Marseille Univ, Universit´e de Toulon, CNRS, IM2NP 13397, Marseille, France; 4LENS, University of Florence, Sesto Fiorentino 50019, Italy; 5Department of Materials Science, University of Milano-Bicocca, Milano, 20125, Italy
Subwavelength-sized dielectric Mie resonators have recently emerged as a promising photonic platform due to the exhibition of electric and magnetic modes. By exploiting solid state dewetting, we obtained SiGe resonators from pre-patterned film with a combination of electron beam lithography and reactive ion etching. We show the improvements respect to optical lithography approach. Through Dark Field characterization we study the Mie resonance peaks against the island dimensions. We integrate SiGe resonators with GaAs/AlGaAs core shell wires, epitaxially grown, to study an implementation of light emitters that exploit the SiGe resonances.
9:15 - 9:30ID: 137
/ TOM6 S01: 3
TOM 6 Optical Materials: crystals, thin films, organic molecules and polymers, syntheses, characterization and devices
Optimization of selective oxidation of AlAs/AlGaAs devices for optical confinement
Giulio Tavani1, Andrea Chiappini2, Alexey Fedorov3, Daniel Chrastina1, Francesco Scotognella4, Erfan Mafakheri3, Stefano Sanguinetti3,5, Monica Bollani3
1L-NESS, Dipartimento Di Fisica del Politecnico di Milano, 22100 Como, Italy; 2IFN-CNR CSMFO Lab & FBK CMM, 38123 Trento, Italy; 3IFN-CNR, L-NESS laboratory, 22100 Como, Italy; 4Politecnico di Milano, Milano, 20133, Italy; 5Department of Materials Science, University of Milano-Bicocca, Milano, 20125, Italy
AlAs oxidation is a crucial process to obtain vertical optical confinement in III-V photonic crystals. Yet, since there is a significant lattice mismatch between AlAs and AlOx, the accumulated stress could cause delamination at the interfaces, especially for a thick AlAs layer. In this work, we have obtained high-quality oxides for both thin (100 nm) and thick (500 nm) AlAs layers. µ-Raman characterization was used to confirm that AlAs is oxidized while the photonic crystal material is not modified. SEM images show that there are no cracks at the interfaces.
9:30 - 9:45ID: 133
/ TOM6 S01: 4
TOM 6 Optical Materials: crystals, thin films, organic molecules and polymers, syntheses, characterization and devices
Enhanced photorefractivity and rare-earth photoluminescence in SnO2 nanocrystals-based photonic glass-ceramics
Thi Ngoc Lam Tran1,2,3, Anna Szczurek1, Stefano Varas1, Cristina Armellini1, Alessandro Carpentiero1, Andrea Chiappini1, Erica Iacob4, Gloria Ischia5, Simone Berneschi6, Gualtiero Nunzi Conti6, Monica Bollani7, Francesco Scotognella2,8, Giancarlo Righini6, Paweł Głuchowski9, Alessandro Chiasera1, Anna Lukowiak9, Maurizio Ferrari1
1IFN-CNR CSMFO Lab. and FBK Photonics Unit, Via alla Cascata 56/C, 38123 Povo, Italy;; 2Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy;; 3Department of Materials Technology, Faculty of Applied Science, Ho Chi Minh City University of Technology and Education, Vo Van Ngan Street 1, Thu Duc District, 720214 Ho Chi Minh City, Vietnam;; 4Fondazione Bruno Kessler, Sensors and Devices, Micro Nano Facility, Via Sommarive 18, Povo, Trento, 38123, Italy;; 5Department of Industrial Engineering, University of Trento, Via Sommarive 9, Povo, Trento, 38123, Italy;; 6MiPLab, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy;; 7CNR‐IFN, P.zza Leonardo da Vinci 32, Milano, 20133 Italy;; 8Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia (IIT), Via Giovanni Pascoli, 70/3, 20133, Milan, Italy;; 9Institute of Low Temperature and Structure Research, PAS, ul. Okólna 2, 50422 Wroclaw, Poland;
This work presents state of the art rare-earth activated SnO2 nanocrystals - based transparent glass-ceramics. With combined enhancements in both photorefractivity and rare-earth photoluminescence, the glass-ceramic has unique benefits as a lasing material. It exhibits high photorefractivity with UV induced refractive index modifications in the order of 10-3. Exploiting its high photorefractivity, optical gratings are fabricated on the glass-ceramic under an energy-efficient direct UV writing process. Furthermore, SnO2 semiconductor nanocrystals are also employed as efficient rare-earth sensitizers enhancing drastically the rare-earth photoluminescence.
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