1
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Peeters WHJ, van Lange VT, Belabbes A, van Hemert MC, Jansen MM, Farina R, van Tilburg MAJ, Verheijen MA, Botti S, Bechstedt F, Haverkort JEM, Bakkers EPAM. Direct bandgap quantum wells in hexagonal Silicon Germanium. Nat Commun 2024; 15:5252. [PMID: 38898007 PMCID: PMC11187182 DOI: 10.1038/s41467-024-49399-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
Silicon is indisputably the most advanced material for scalable electronics, but it is a poor choice as a light source for photonic applications, due to its indirect band gap. The recently developed hexagonal Si1-xGex semiconductor features a direct bandgap at least for x > 0.65, and the realization of quantum heterostructures would unlock new opportunities for advanced optoelectronic devices based on the SiGe system. Here, we demonstrate the synthesis and characterization of direct bandgap quantum wells realized in the hexagonal Si1-xGex system. Photoluminescence experiments on hex-Ge/Si0.2Ge0.8 quantum wells demonstrate quantum confinement in the hex-Ge segment with type-I band alignment, showing light emission up to room temperature. Moreover, the tuning range of the quantum well emission energy can be extended using hexagonal Si1-xGex/Si1-yGey quantum wells with additional Si in the well. These experimental findings are supported with ab initio bandstructure calculations. A direct bandgap with type-I band alignment is pivotal for the development of novel low-dimensional light emitting devices based on hexagonal Si1-xGex alloys, which have been out of reach for this material system until now.
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Affiliation(s)
- Wouter H J Peeters
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Victor T van Lange
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Abderrezak Belabbes
- Department of Physics, Sultan Qaboos University, P.O. Box 123, Muscat, Oman
- Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Max C van Hemert
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Marvin Marco Jansen
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Riccardo Farina
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Marvin A J van Tilburg
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Marcel A Verheijen
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
- Eurofins Materials Science Netherlands BV, Eindhoven, The Netherlands
| | - Silvana Botti
- Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Jena, Germany
- Research Center Future Energy Materials and Systems of the University Alliance Ruhr and Interdisciplinary Centre for Advanced Materials Simulation, Ruhr University Bochum, Universitätsstraße 150, Bochum, Germany
| | - Friedhelm Bechstedt
- Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Jos E M Haverkort
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Erik P A M Bakkers
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands.
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2
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Yuan Q, Huang J, Li A, Lu N, Lu W, Zhu Y, Zhang Z. Engineering Semi-Reversed Quantum Well Photocatalysts for Highly-Efficient Solar-to-Fuels Conversion. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311764. [PMID: 38181062 DOI: 10.1002/adma.202311764] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/29/2023] [Indexed: 01/07/2024]
Abstract
Semiconductor quantum wells (QWs) exhibit high charge-utilization efficiency for light-emitting applications due to their strong charge confinement effect. Inspired by this effect, herein, this work proposes a new idea to significantly improve the photo-generated charge separation for attaining a highly-efficient solar-to-fuels conversion process through "semi-reversing" the conventional QWs to confine only the photo-generated electrons. This electron confinement-improved charge separation is implemented in the well-designed model of the CdS/TiO2/CdS semi-reversed QW (SRQW) structure. The latter is fabricated by selectively assembling CdS quantum dots (QDs) onto the {101} facets (ultra-thin edge regions) of the TiO2 nanosheets (NSs). Upon light excitation, the photo-generated electrons of SRQW can be confined on the TiO2-{101} facets in the vicinity of the CdS/TiO2 hetero-interface. Thereby, the continuous multi-electron injection to the adsorbed reactants on the interfacial active-sites is significantly accelerated. Thus, the CdS/TiO2/CdS SRQW exhibits ≈35.7 and ≈56.0-fold enhancements on the photocatalytic activities for water and CO2 reduction, respectively, compared to those of pure TiO2. Correspondingly, its CH4-product selectivity is increased by ≈180%. This work provides a novel charge separation mechanism, which is of great importance for the design of the next-generation quantum-sized photocatalysts for solar-to-fuels conversion.
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Affiliation(s)
- Qing Yuan
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
- Dalian Key Laboratory of Low-Dimensional Semiconductor Optoelectronic Materials and Applications, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Jindou Huang
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
- Dalian Key Laboratory of Low-Dimensional Semiconductor Optoelectronic Materials and Applications, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Ang Li
- Faculty of Materials and Manufacturing, Beijing Key Lab of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing, 100124, P. R. China
| | - Na Lu
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
- Dalian Key Laboratory of Low-Dimensional Semiconductor Optoelectronic Materials and Applications, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Wei Lu
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
- Dalian Key Laboratory of Low-Dimensional Semiconductor Optoelectronic Materials and Applications, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Yongan Zhu
- Dalian Key Laboratory of Low-Dimensional Semiconductor Optoelectronic Materials and Applications, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
| | - Zhenyi Zhang
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials and Devices of Liaoning Province, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
- Dalian Key Laboratory of Low-Dimensional Semiconductor Optoelectronic Materials and Applications, School of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, P. R. China
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3
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Wang L, Wang B, Zhang Y, Meng L, Sun H, Liu T, Zhang N, Jiang Z, Hu H. Infrared broadband enhancement of responsivity in Ge photodetectors decorated with Au nanoparticles. OPTICS EXPRESS 2021; 29:12941-12949. [PMID: 33985039 DOI: 10.1364/oe.423899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
A broadband, high-performance infrared Ge photodetector decorated with Au nanoparticles (NPs) is proposed. Photoelectronic characterization demonstrated that the responsivity of devices decorated with Au NPs is as high as 3.95 A/W at a wavelength of 1550 nm. Compared with a Ge photodetector without Au NPs, the responsivity of a device decorated with Au NPs is significantly increased, i.e., by more than 10 times in the entire range of infrared communication wavelengths, including the O, E, S, C, L, and U bands. The increase is ascribed to type-II energy-band alignment between Ge covered with Au NPs and bare Ge, instead of the localized surface-plasmon-resonance effect. The type-II energy-band alignment enhances the spatial electron-hole separation and restrains the electron-hole recombination, thus a larger photocurrent is observed. These results reflect the potential of this approach for achieving broadband, high-performance Ge photodetectors operating in the near-infrared communication band.
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Wang L, Zhang Y, Sun H, You J, Miao Y, Dong Z, Liu T, Jiang Z, Hu H. Nanoscale growth of a Sn-guided SiGeSn alloy on Si (111) substrates by molecular beam epitaxy. NANOSCALE ADVANCES 2021; 3:997-1004. [PMID: 36133284 PMCID: PMC9419757 DOI: 10.1039/d0na00680g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 11/18/2020] [Indexed: 06/16/2023]
Abstract
Here, SiGeSn nanostructures were grown via molecular beam epitaxy on a Si (111) substrate with the assistance of Sn droplets. Owing to the thermal effect and the compressive strain induced by a lattice mismatch, Si and Sn atoms were successfully incorporated into the Ge matrix during the Sn-guided Ge deposition process. A low growth temperature of 350 °C produced a variety of SiGeSn nanostructures of different sizes, attributed to the variation of the initial Sn droplet size. Using energy-dispersive X-ray spectroscopy, the Sn, Si and Ge contents of a defect-free SiGeSn nanoisland were approximately determined to be 0.05, 0.09 and 0.86, respectively. Furthermore, as the growth temperature increased past 600 °C, the growth direction of the nanostructure was changed thermally from out-of-plane to in-plane. Meanwhile, the stacked SiGeSn nanowires grown along the 〈112〉 direction remained defect-free, though some threading dislocations were observed in the smooth SiGeSn nanowires along the 〈110〉 direction. These results offer a novel method to grow Si-based SiGeSn nanostructures while possessing important implications for fabricating further optoelectronic devices.
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Affiliation(s)
- Liming Wang
- Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University Xi'an 710071 China
| | - Yichi Zhang
- Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University Xi'an 710071 China
| | - Hao Sun
- School of Physics and Optoelectronic Engineering, Xidian University Xi'an 710071 China
| | - Jie You
- Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University Xi'an 710071 China
| | - Yuanhao Miao
- Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University Xi'an 710071 China
| | - Zuoru Dong
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University Shanghai 200433 China
| | - Tao Liu
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University Shanghai 200433 China
| | - Zuimin Jiang
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University Shanghai 200433 China
| | - Huiyong Hu
- Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University Xi'an 710071 China
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5
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Giambra M, Mišeikis V, Pezzini S, Marconi S, Montanaro A, Fabbri F, Sorianello V, Ferrari AC, Coletti C, Romagnoli M. Wafer-Scale Integration of Graphene-Based Photonic Devices. ACS NANO 2021; 15:3171-3187. [PMID: 33522789 PMCID: PMC7905876 DOI: 10.1021/acsnano.0c09758] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/21/2021] [Indexed: 05/13/2023]
Abstract
Graphene and related materials can lead to disruptive advances in next-generation photonics and optoelectronics. The challenge is to devise growth, transfer and fabrication protocols providing high (≥5000 cm2 V-1 s-1) mobility devices with reliable performance at the wafer scale. Here, we present a flow for the integration of graphene in photonics circuits. This relies on chemical vapor deposition (CVD) of single layer graphene (SLG) matrices comprising up to ∼12000 individual single crystals, grown to match the geometrical configuration of the devices in the photonic circuit. This is followed by a transfer approach which guarantees coverage over ∼80% of the device area, and integrity for up to 150 mm wafers, with room temperature mobility ∼5000 cm2 V-1 s-1. We use this process flow to demonstrate double SLG electro-absorption modulators with modulation efficiency ∼0.25, 0.45, 0.75, 1 dB V-1 for device lengths ∼30, 60, 90, 120 μm. The data rate is up to 20 Gbps. Encapsulation with single-layer hexagonal boron nitride (hBN) is used to protect SLG during plasma-enhanced CVD of Si3N4, ensuring reproducible device performance. The processes are compatible with full automation. This paves the way for large scale production of graphene-based photonic devices.
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Affiliation(s)
- Marco
A. Giambra
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
- INPHOTEC, Via G. Moruzzi 1, 56124 Pisa, Italy
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Vaidotas Mišeikis
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Sergio Pezzini
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- NEST,
Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Simone Marconi
- Photonic
Networks and Technologies Lab, Tecip Institute, Scuola Superiore Sant’Anna, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Alberto Montanaro
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Filippo Fabbri
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- NEST,
Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Vito Sorianello
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Andrea C. Ferrari
- Cambridge
Graphene Centre, Cambridge University, 9 J.J. Thompson, Cambridge, U.K.
| | - Camilla Coletti
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Marco Romagnoli
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
- INPHOTEC, Via G. Moruzzi 1, 56124 Pisa, Italy
- CamGraPhiC, Via Moruzzi 1, 56124 Pisa, Italy
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6
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Agarwal H, Terrés B, Orsini L, Montanaro A, Sorianello V, Pantouvaki M, Watanabe K, Taniguchi T, Thourhout DV, Romagnoli M, Koppens FHL. 2D-3D integration of hexagonal boron nitride and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators. Nat Commun 2021; 12:1070. [PMID: 33594048 PMCID: PMC7887197 DOI: 10.1038/s41467-021-20926-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/18/2020] [Indexed: 11/18/2022] Open
Abstract
Electro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene-based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This combination of materials allows for a high-quality modulator device with high performances: a ~39 GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high-speed modulators. This 2D-3D dielectric integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs. Here, three-dimensional hafnium oxide and two-dimensional hexagonal boron nitride are integrated in the insulating section of double-layer graphene optical modulators, leading to a maximum bandwidth of 39 GHz and enhanced modulation efficiency.
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Affiliation(s)
- Hitesh Agarwal
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain
| | - Bernat Terrés
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain.
| | - Lorenzo Orsini
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain.,Dipartimento di Fisica "E. Fermi", Università di Pisa, Pisa, 56127, Italy
| | - Alberto Montanaro
- Consorzio Nazionale per le Telecomunicazioni (CNIT), Photonic Networks and Technologies National Laboratory, Pisa, 56124, Italy
| | - Vito Sorianello
- Consorzio Nazionale per le Telecomunicazioni (CNIT), Photonic Networks and Technologies National Laboratory, Pisa, 56124, Italy
| | | | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tuskuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, 305-0044, Japan
| | - Dries Van Thourhout
- Photonics Research Group, Department of Information Technology, Ghent University-IMEC, Gent, 9000, Belgium
| | - Marco Romagnoli
- Consorzio Nazionale per le Telecomunicazioni (CNIT), Photonic Networks and Technologies National Laboratory, Pisa, 56124, Italy
| | - Frank H L Koppens
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain. .,ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona, 08010, Spain.
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Analysis of Optical Integration between Si3N4 Waveguide and a Ge-Based Optical Modulator Using a Lateral Amorphous GeSi Taper at the Telecommunication Wavelength of 1.55 µm. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9183846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We report on the theoretical investigation of using an amorphous Ge0.83Si0.17 lateral taper to enable a low-loss small-footprint optical coupling between a Si3N4 waveguide and a low-voltage Ge-based Franz–Keldysh optical modulator on a bulk Si substrate using 3D Finite-Difference Time-Domain (3D-FDTD) simulation at the optical wavelength of 1550 nm. Despite a large refractive index and optical mode size mismatch between Si3N4 and the Ge-based modulator, the coupling structure rendered a good coupling performance within fabrication tolerance of advanced complementary metal-oxide semiconductor (CMOS) processes. For integrated optical modulator performance, the Si3N4-waveguide-integrated Ge-based on Si optical modulators could simultaneously provide workable values of extinction ratio (ER) and insertion loss (IL) for optical interconnect applications with a compact footprint.
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