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1. Fabrication of Localized Silicon-on-Insulator Based Rhombus-Shaped Channels in Silicon

   Ogini, Martins; Voyantzis, Mitchell; Koech, Philemon; Francis, Aneeta; Mohan, Susmitha; Deo, Makarand; Albin, Sacharia. (May 2019, ECS Meeting Abstracts)

   null (Ed.)

   Fabricating localized silicon-on-insulator (LSOI) on bulk silicon eliminates the need for using expensive SOI wafers for silicon waveguides and MEMS applications. One of the most important building blocks in silicon photonics is optical waveguide, which usually consists of silicon surrounded by silicon dioxide with refractive indices of 3.5 and 1.5, respectively. It was observed that the SOI wafer puts restrictions on the integration of electronics and photonics because the buried oxide is too thin for field confinement. Hence, fabrication of LSOI in standard silicon wafers is considered to have precise control of the oxide thickness which will lead to effective integration of electronic and photonic devices. We used rhombus-shaped channel method in the fabrication of LSOI structure that can be produced on any part of a bulk silicon wafer. 

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2. Indistinguishable photons from an artificial atom in silicon photonics

   https://doi.org/10.1038/s41467-024-51265-1  

   Komza, Lukasz; Samutpraphoot, Polnop; Odeh, Mutasem; Tang, Yu-Lung; Mathew, Milena; Chang, Jiu; Song, Hanbin; Kim, Myung-Ki; Xiong, Yihuang; Hautier, Geoffroy; et al (August 2024, Nature Communications)

   Abstract Silicon is the ideal material for building electronic and photonic circuits at scale. Integrated photonic quantum technologies in silicon offer a promising path to scaling by leveraging advanced semiconductor manufacturing and integration capabilities. However, the lack of deterministic quantum light sources and strong photon-photon interactions in silicon poses a challenge to scalability. In this work, we demonstrate an indistinguishable photon source in silicon photonics based on an artificial atom. We show that a G center in a silicon waveguide can generate high-purity telecom-band single photons. We perform high-resolution spectroscopy and time-delayed two-photon interference to demonstrate the indistinguishability of single photons emitted from a G center in a silicon waveguide. Our results show that artificial atoms in silicon photonics can source single photons suitable for photonic quantum networks and processors. 

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3. Gas-phase formation of silicon monoxide via non-adiabatic reaction dynamics and its role as a building block of interstellar silicates

   https://doi.org/10.1039/D2CP02188A  

   He, Chao; Luo, Yuheng; Doddipatla, Srinivas; Yang, Zhenghai; Millar, Tom J.; Sun, Rui; Kaiser, Ralf I. (August 2022, Physical Chemistry Chemical Physics)

   Silicon monoxide (SiO) is classified as a key precursor and fundamental molecular building block to interstellar silicate nanoparticles, which play an essential role in the synthesis of molecular building blocks connected to the Origins of Life. In the cold interstellar medium, silicon monoxide is of critical importance in initiating a series of elementary chemical reactions leading to larger silicon oxides and eventually to silicates. To date, the fundamental formation mechanisms and chemical dynamics leading to gas phase silicon monoxide have remained largely elusive. Here, through a concerted effort between crossed molecular beam experiments and electronic structure calculations, it is revealed that instead of forming highly-stable silicon dioxide (SiO 2 ), silicon monoxide can be formed via a barrierless, exoergic, single-collision event between ground state molecular oxygen and atomic silicon involving non-adiabatic reaction dynamics through various intersystem crossings. Our research affords persuasive evidence for a likely source of highly rovibrationally excited silicon monoxide in cold molecular clouds thus initiating the complex chain of exoergic reactions leading ultimately to a population of silicates at low temperatures in our Galaxy. 

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4. Approaches to the development of environmentally friendly and resource-saving technology for solar-grade silicon production

   https://doi.org/10.1557/adv.2019.311  

   Karabanov, Sergey M.; Suvorov, Dmitriy V.; Tarabrin, Dmitry Y.; Slivkin, Evgeniy V.; Karabanov, Andrey S.; Belyakov, Oleg A.; Trubitsyn, Andrey A.; Serebryakov, Andrey (January 2019, MRS Advances)

   ABSTRACT Currently, the main material for the production of solar cells is still silicon. More than 70% of the global production of solar cells are silicon based. For solar-grade silicon production the technologies based on the reduction of silicon from organosilicon compounds are mainly used. These technologies are energy-consuming, highly explosive and unsustainable. The present paper studies the technology of purification of metallurgical-grade silicon by vacuum-thermal and plasma-chemical treatment of silicon melt under electromagnetic stirring using numerical simulation and compares this technology with the existing ones (silane technologies and Elkem Solar silicon (ESS) production process) in terms of energy consumption, environmental safety and the process scalability. It is shown that the proposed technology is environmentally safe, scalable and has low power consumption. The final product of this technology is multicrystalline silicon, ready for silicon wafer production. 

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5. Demonstration of 4H-silicon carbide on an aluminum nitride integrated photonic platform

   https://doi.org/10.1364/OL.521157  

   Wang, Ruixuan; Li, Jingwei; Cai, Lutong; Li, Qing (January 2024, Optics Letters)

   The existing silicon-carbide-on-insulator photonic platform utilizes a thin layer of silicon dioxide under silicon carbide (SiC) to provide optical confinement and mode isolation. Here, we replace the underneath silicon dioxide layer with 1-µm-thick aluminum nitride and demonstrate a 4H-silicon-carbide-on-aluminum-nitride integrated photonic platform for the first time to our knowledge. Efficient grating couplers, low-loss waveguides, and compact microring resonators with intrinsic quality factors up to 210,000 are fabricated. In addition, by undercutting the aluminum nitride layer, the intrinsic quality factor of the silicon carbide microring is improved by nearly one order of magnitude (1.8 million). Finally, an optical pump–probe method is developed to measure the thermal conductivity of the aluminum nitride layer, which is estimated to be over 30 times of that of silicon dioxide. 

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