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Shu Q, Huang P, Yang F, Yang L, Chen L. Study on crystal growth of Ge/Si quantum dots at different Ge deposition by using magnetron sputtering technique. Sci Rep 2023; 13:7511. [PMID: 37161032 PMCID: PMC10169779 DOI: 10.1038/s41598-023-34284-8] [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: 02/02/2023] [Accepted: 04/27/2023] [Indexed: 05/11/2023] Open
Abstract
We investigated the growth and evolution of Si-based Ge quantum dots (Ge/Si QDs) under low Ge deposition (1.2-4.4 nm thick) using magnetron sputtering. The morphology and structure of QDs were analyzed with the help of an atomic force microscope (AFM), scanning electron microscope, transmission electron microscope, Raman, surface energy theory and dynamics theory, the photoelectric properties of QDs were characterized by photoluminescence (PL) spectra. The results showed that the growth mechanism of QDs conformed to Stranski-Krastanow mode, but the typical thickness of the wetting layer was nearly three times higher than those derived from conventional technologies such as molecular beam epitaxy, chemical vapor deposition, solid phase epitaxy and so on. Meanwhile, the shape evolution of QDs was very different from existing reports. The specific internal causes of these novel phenomena were analyzed and confirmed and reported in this paper. In addition, the AFM, Raman, and PL tests all indicated that the QDs grown when 3.4 nm Ge was deposited have the most excellent morphology, structure, and optoelectronic performance. Our work lays a foundation for further exploration of the controllable growth of QDs at high deposition rates, which is a new way to realize the industrialization of QDs used for future devices.
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Affiliation(s)
- Qijiang Shu
- Institute of Information, Yunnan University of Chinese Medicine, Kunming, 650500, China
| | - Pengru Huang
- School of Material Science and Engineering, Guangxi Key Laboratory of Information Materials and Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials, Guilin University of Electronic Technology, Guilin, 541004, China
| | - Fuhua Yang
- Institute of Information, Yunnan University of Chinese Medicine, Kunming, 650500, China
| | - Linjing Yang
- Institute of Information, Yunnan University of Chinese Medicine, Kunming, 650500, China
| | - Lei Chen
- College of Chinese Materia Medica, Yunnan University of Chinese Medicine, Kunming, 650500, China.
- Faculty of Narcotics Control, Yunnan Police College, Kunming, 650223, China.
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Stepikhova MV, Dyakov SA, Peretokin AV, Shaleev MV, Rodyakina EE, Novikov AV. Interaction of Ge(Si) Self-Assembled Nanoislands with Different Modes of Two-Dimensional Photonic Crystal. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:2687. [PMID: 35957118 PMCID: PMC9370173 DOI: 10.3390/nano12152687] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 06/01/2023]
Abstract
The interaction of Ge(Si)/SOI self-assembled nanoislands with modes of photonic crystal slabs (PCS) with a hexagonal lattice is studied in detail. Appropriate selection of the PCS parameters and conditions for collecting the photoluminescence (PL) signal allowed to distinguish the PCS modes of different physical nature, particularly the radiative modes and modes associated to the bound states in the continuum (BIC). It is shown that the radiative modes with relatively low Q-factors could provide a increase greater than an order of magnitude in the integrated PL intensity in the wavelength range of 1.3-1.55 µm compared to the area outside of PCS at room temperature. At the same time, the interaction of Ge(Si) islands emission with the BIC-related modes provides the peak PL intensity increase of more than two orders of magnitude. The experimentally measured Q-factor of the PL line associated with the symmetry-protected BIC mode reaches the value of 2600.
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Affiliation(s)
- Margarita V. Stepikhova
- Institute for Physics of Microstructures Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Sergey A. Dyakov
- Skolkovo Institute of Science and Technology, 143026 Moscow, Russia
| | - Artem V. Peretokin
- Institute for Physics of Microstructures Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
- Radiophysical Department, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
| | - Mikhail V. Shaleev
- Institute for Physics of Microstructures Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Ekaterina E. Rodyakina
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Physical Department, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Alexey V. Novikov
- Institute for Physics of Microstructures Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
- Radiophysical Department, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
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Chowdhury D, Mondal S, Secchi M, Giordano MC, Vanzetti L, Barozzi M, Bersani M, Giubertoni D, Buatier de Mongeot F. Omnidirectional and broadband photon harvesting in self-organized Ge columnar nanovoids. NANOTECHNOLOGY 2022; 33:305304. [PMID: 35385839 DOI: 10.1088/1361-6528/ac64ae] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
Highly porous Germanium surfaces with uniformly distributed columnar nanovoid structures are fabricated over a large area (wafer scale) by large fluence Sn+irradiation through a thin silicon nitride layer. The latter represents a one-step highly reproducible approach with no material loss to strongly increase photon harvesting into a semiconductor active layer by exploiting the moth-eye antireflection effect. The ion implantation through the nitride cap layer allows fabricating porous nanostructures with high aspect ratio, which can be tailored by varying ion fluence. By comparing the reflectivity of nanoporous Ge films with a flat reference we demonstrate a strong and omnidirectional reduction in the optical reflectivity by a factor of 96% in the selected spectral regions around 960 nm and by a factor of 67.1% averaged over the broad spectral range from 350 to 1800 nm. Such highly anti-reflective nanostructured Ge films prepared over large-areas with a self-organized maskless approach have the potential to impact real world applications aiming at energy harvesting.
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Affiliation(s)
- Debasree Chowdhury
- Dipartimento di Fisica, Università degli Studi di Genova, via Dodecaneso 33, I-16146, Genova, Italy
| | - Shyamal Mondal
- Sensors and Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123, Trento, Italy
| | - Maria Secchi
- Sensors and Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123, Trento, Italy
| | - Maria Caterina Giordano
- Dipartimento di Fisica, Università degli Studi di Genova, via Dodecaneso 33, I-16146, Genova, Italy
| | - Lia Vanzetti
- Sensors and Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123, Trento, Italy
| | - Mario Barozzi
- Sensors and Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123, Trento, Italy
| | - Massimo Bersani
- Sensors and Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123, Trento, Italy
| | - Damiano Giubertoni
- Sensors and Devices, Fondazione Bruno Kessler, Via Sommarive 18, I-38123, Trento, Italy
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Schuster J, Aberl J, Vukušić L, Spindlberger L, Groiss H, Fromherz T, Brehm M, Schäffler F. Photoluminescence enhancement by deterministically site-controlled, vertically stacked SiGe quantum dots. Sci Rep 2021; 11:20597. [PMID: 34663889 PMCID: PMC8523567 DOI: 10.1038/s41598-021-99966-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/05/2021] [Indexed: 11/09/2022] Open
Abstract
The Si/SiGe heterosystem would be ideally suited for the realization of complementary metal-oxide-semiconductor (CMOS)-compatible integrated light sources, but the indirect band gap, exacerbated by a type-II band offset, makes it challenging to achieve efficient light emission. We address this problem by strain engineering in ordered arrays of vertically close-stacked SiGe quantum dot (QD) pairs. The strain induced by the respective lower QD creates a preferential nucleation site for the upper one and strains the upper QD as well as the Si cap above it. Electrons are confined in the strain pockets in the Si cap, which leads to an enhanced wave function overlap with the heavy holes near the upper QD’s apex. With a thickness of the Si spacer between the stacked QDs below 5 nm, we separated the functions of the two QDs: The role of the lower one is that of a pure stressor, whereas only the upper QD facilitates radiative recombination of QD-bound excitons. We report on the design and strain engineering of the QD pairs via strain-dependent Schrödinger-Poisson simulations, their implementation by molecular beam epitaxy, and a comprehensive study of their structural and optical properties in comparison with those of single-layer SiGe QD arrays. We find that the double QD arrangement shifts the thermal quenching of the photoluminescence signal at higher temperatures. Moreover, detrimental light emission from the QD-related wetting layers is suppressed in the double-QD configuration.
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Affiliation(s)
- Jeffrey Schuster
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria.
| | - Johannes Aberl
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria
| | - Lada Vukušić
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria
| | - Lukas Spindlberger
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria
| | - Heiko Groiss
- Christian Doppler Laboratory for Nanoscale Phase Transformations, Center for Surface and Nanoanalytics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria
| | - Thomas Fromherz
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria
| | - Moritz Brehm
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria
| | - Friedrich Schäffler
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040, Linz, Austria
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Turner EM, Campbell Q, Pizarro J, Yang H, Sapkota KR, Lu P, Baczewski AD, Wang GT, Jones KS. Controlled Formation of Stacked Si Quantum Dots in Vertical SiGe Nanowires. NANO LETTERS 2021; 21:7905-7912. [PMID: 34582219 DOI: 10.1021/acs.nanolett.1c01670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We demonstrate the ability to fabricate vertically stacked Si quantum dots (QDs) within SiGe nanowires with QD diameters down to 2 nm. These QDs are formed during high-temperature dry oxidation of Si/SiGe heterostructure pillars, during which Ge diffuses along the pillars' sidewalls and encapsulates the Si layers. Continued oxidation results in QDs with sizes dependent on oxidation time. The formation of a Ge-rich shell that encapsulates the Si QDs is observed, a configuration which is confirmed to be thermodynamically favorable with molecular dynamics and density functional theory. The type-II band alignment of the Si dot/SiGe pillar suggests that charge trapping on the Si QDs is possible, and electron energy loss spectra show that a conduction band offset of at least 200 meV is maintained for even the smallest Si QDs. Our approach is compatible with current Si-based manufacturing processes, offering a new avenue for realizing Si QD devices.
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Affiliation(s)
- Emily M Turner
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Quinn Campbell
- Quantum Computer Science Department, Sandia National Laboratories, Albuquerque, New Mexico 87158, United States
| | - Joaquín Pizarro
- Department of Computer Engineering, University of Cádiz, Puerto Real 11519, Spain
| | - Hongbin Yang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Keshab R Sapkota
- Advanced Materials Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87158, United States
| | - Ping Lu
- Department of Materials Characterization and Performance, Sandia National Laboratories, Albuquerque, New Mexico 87158, United States
| | - Andrew D Baczewski
- Quantum Computer Science Department, Sandia National Laboratories, Albuquerque, New Mexico 87158, United States
| | - George T Wang
- Advanced Materials Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87158, United States
| | - Kevin S Jones
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
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Recent Advances on Properties and Utility of Nanomaterials Generated from Industrial and Biological Activities. CRYSTALS 2021. [DOI: 10.3390/cryst11060634] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Today is the era of nanoscience and nanotechnology, which find applications in the field of medicine, electronics, and environmental remediation. Even though nanotechnology is in its emerging phase, it continues to provide solutions to numerous challenges. Nanotechnology and nanoparticles are found to be very effective because of their unique chemical and physical properties and high surface area, but their high cost is one of the major hurdles to its wider application. So, the synthesis of nanomaterials, especially 2D nanomaterials from industrial, agricultural, and other biological activities, could provide a cost-effective technique. The nanomaterials synthesized from such waste not only minimize pollution, but also provide an eco-friendly approach towards the utilization of the waste. In the present review work, emphasis has been given to the types of nanomaterials, different methods for the synthesis of 2D nanomaterials from the waste generated from industries, agriculture, and their application in electronics, medicine, and catalysis.
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Banerjee P, Roy C, Jiménez JJ, Morales FM, Bhattacharyya S. Atomically resolved 3D structural reconstruction of small quantum dots. NANOSCALE 2021; 13:7550-7557. [PMID: 33928976 DOI: 10.1039/d1nr00466b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Semiconducting quantum dots (QDs) have potential applications in light-emitting diodes, single-photon sources and quantum computing due to shape-dependent (opto) electronic properties. Atomic resolution 3D-structure determination is important in understanding growth kinetics and improving device performance. 3D-reconstruction of large QDs was reported using characterization techniques like atomic force microscopy, atom probe tomography and tilt series electron tomography, but, still, atomic resolution tomography of QDs, especially those sized below 10 nm, is a challenge. Inline-3D-holography is an emerging and promising technique to perform atomic resolution tomography at low electron doses. In the present study, atomically resolved 3D structures of QDs were reconstructed using inline-3D-holography, implemented on InN QDs (<10 nm) grown on a Si substrate. The residual amorphous glue distorts the exit surface geometry; hence an error correction method was proposed. This is the first experimental evidence of pre-pyramid shaped 3D structure of QDs sized below 10 nm that supports theoretical predictions.
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Affiliation(s)
- Pritam Banerjee
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
| | - Chiranjit Roy
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
| | - Juan Jesús Jiménez
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cádiz, Spain and Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, 11510 Cádiz, Spain
| | - Francisco Miguel Morales
- IMEYMAT: Institute of Research on Electron Microscopy and Materials, University of Cádiz, Spain and Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Puerto Real, 11510 Cádiz, Spain
| | - Somnath Bhattacharyya
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
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One-Stage Formation of Two-Dimensional Photonic Crystal and Spatially Ordered Arrays of Self-Assembled Ge(Si) Nanoislandson Pit-Patterned Silicon-On-Insulator Substrate. NANOMATERIALS 2021; 11:nano11040909. [PMID: 33918328 PMCID: PMC8065389 DOI: 10.3390/nano11040909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 11/17/2022]
Abstract
A new approach to improve the light-emitting efficiency of Ge(Si) quantum dots (QDs) by the formation of an ordered array of QDs on a pit-patterned silicon-on-insulator (SOI) substrate is presented. This approach makes it possible to use the same pre-patterned substrate both for the growth of spatially ordered QDs and for the formation of photonic crystal (PhC) in which QDs are embedded. The periodic array of deep pits on the SOI substrate simultaneously serves as a template for spatially ordering of QDs and the basis for two-dimensional PhCs. As a result of theoretical and experimental studies, the main regularities of the QD nucleation on the pre-patterned surface with deep pits were revealed. The parameters of the pit-patterned substrate (the period of the location of the pits, the pit shape, and depth) providing a significant increase of the QD luminescence intensity due to the effective interaction of QD emission with the PhC modes are found.
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In-Situ Annealing and Hydrogen Irradiation of Defect-Enhanced Germanium Quantum Dot Light Sources on Silicon. CRYSTALS 2020. [DOI: 10.3390/cryst10050351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
While light-emitting nanostructures composed of group-IV materials fulfil the mandatory compatibility with CMOS-fabrication methods, factors such as the structural stability of the nanostructures upon thermal annealing, and the ensuing photoluminescence (PL) emission properties, are of key relevance. In addition, the possibility of improving the PL efficiency by suitable post-growth treatments, such as hydrogen irradiation, is important too. We address these issues for self-assembled Ge quantum dots (QDs) that are co-implanted with Ge ions during their epitaxial growth. The presence of defects introduced by the impinging Ge ions results in pronounced PL-emission at telecom wavelengths up to room temperature (RT) and above. This approach allows us to overcome the severe limitations of light generation in the indirect-band-gap group-IV materials. By performing in-situ annealing, we demonstrate a high PL-stability of the defect-enhanced QD (DEQD) system against thermal treatment up to 600 °C for at least 2 h, even though the Ge QDs are structurally affected by Si/Ge intermixing via bulk diffusion. The latter, in turn, allows for emission tuning of the DEQDs over the entire telecom wavelength range from 1.3 µm to 1.55 µm. Two quenching mechanisms for light-emission are discussed; first, luminescence quenching at high PL recording temperatures, associated with the thermal escape of holes to the surrounding wetting layer; and second, annealing-induced PL-quenching at annealing temperatures >650 °C, which is associated with a migration of the defect complex out of the QD. We show that low-energy ex-situ proton irradiation into the Si matrix further improves the light emission properties of the DEQDs, whereas proton irradiation-related optically active G-centers do not affect the room temperature luminescence properties of DEQDs.
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Dixit GK, Dhankhar M, Ranganathan M. Orientational competition in quantum dot growth in Si–Ge heteroepitaxy on pit-patterned Si(001) substrates. Phys Chem Chem Phys 2020; 22:7643-7649. [DOI: 10.1039/d0cp00542h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Growth of quantum dots on patterned substrates shows orientation dependent localization.
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Affiliation(s)
| | - Monika Dhankhar
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur
- India
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