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Shen Y, Chen W, Sun B. Research progress of out-of-plane GeSn nanowires. NANOTECHNOLOGY 2024; 35:242002. [PMID: 38467062 DOI: 10.1088/1361-6528/ad3250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 03/11/2024] [Indexed: 03/13/2024]
Abstract
With the increasing integration density of silicon-based circuits, traditional electrical interconnections have shown their technological limitations. In recent years, GeSn materials have attracted great interest due to their potential direct bandgap transition and compatibility with silicon-based technologies. GeSn materials, including GeSn films, GeSn alloys, and GeSn nanowires, are adjustable, scalable, and compatible with silicon. GeSn nanowires, as one-dimensional (1D) nanomaterials, including out-of-plane GeSn nanowires and in-plane GeSn nanowires, have different properties from those of bulk materials due to their distinctive structures. However, the synthesis and potential applications of out of plane GeSn nanowires are rarely compared to highlighting their current development status and research trends in relevant review papers. In this article, we present the preparation of out-of-plane GeSn nanowires using top-down (etching and lithography) and bottom-up (vapor-liquid-solid) growth mechanism in the vapor-phase method and supercritical fluid-liquid-solid, solution-liquid-solid, and solvent vapor growth mechanisms in the liquid-phase method) methods. Specifically, the research progress on typical out of plane GeSn nanowires are discussed, while some current development bottlenecks are also been identified. Finally, it is also provided a brief description of the applications of out-of-plane GeSn nanowires with various Sn contents and morphologies.
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Affiliation(s)
- Ya Shen
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, People's Republic of China
| | - Wanghua Chen
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, People's Republic of China
| | - Bai Sun
- Frontier Institute of Science and Technology (FIST), Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
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2
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Zhang N, Yan J, Wang L, Zhang J, Zhang Z, Miao T, Zheng C, Jiang Z, Hu H, Zhong Z. Hexagonal-Ge Nanostructures with Direct-Bandgap Emissions in a Si-Based Light-Emitting Metasurface. ACS NANO 2024; 18:328-336. [PMID: 38147566 DOI: 10.1021/acsnano.3c06279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Si-based emitters have been of great interest as an ideal light source for monolithic optical-electronic integrated circuits (MOEICs) on Si substrates. However, the general Si-based material is a diamond structure of cubic lattice with an indirect band gap, which cannot emit light efficiently. Here, hexagonal-Ge (H-Ge) nanostructures within a light-emitting metasurface consisting of a cubic-SiGe nanodisk array are reported. The H-Ge nanostructure is naturally formed within the cubic-Ge epitaxially grown on Si (001) substrates due to the strain-induced nanoscale crystal structure transformation assisted by far-from-equilibrium growth conditions. The direct-bandgap features of H-Ge nanostructures are observed and discussed, including a rather strong and linearly power-dependent photoluminescence (PL) peak around 1562 nm at room temperature and temperature-insensitive PL spectrum near room temperature. Given the direct-bandgap nature, the heterostructure of H-Ge/C-Ge, and the compatibility with the sophisticated Si technology, the H-Ge nanostructure has great potential for innovative light sources and other functional devices, particularly in Si-based MOEICs.
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Affiliation(s)
- Ningning Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
- Key Laboratory of Analog Integrated Circuits and Systems, Ministry of Education, School of Microelectronics, Xidian University, Xi'an 710071, P. R. China
| | - Jia Yan
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
| | - Liming Wang
- Key Laboratory of Analog Integrated Circuits and Systems, Ministry of Education, School of Microelectronics, Xidian University, Xi'an 710071, P. R. China
| | - Jiarui Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
| | - Zhifang Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
| | - Tian Miao
- Key Laboratory of Analog Integrated Circuits and Systems, Ministry of Education, School of Microelectronics, Xidian University, Xi'an 710071, P. R. China
| | - Changlin Zheng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
| | - Zuimin Jiang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
| | - Huiyong Hu
- Key Laboratory of Analog Integrated Circuits and Systems, Ministry of Education, School of Microelectronics, Xidian University, Xi'an 710071, P. R. China
| | - Zhenyang Zhong
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, P. R. China
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3
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Peretokin AV, Yurasov DV, Stepikhova MV, Shaleev MV, Yablonskiy AN, Shengurov DV, Dyakov SA, Rodyakina EE, Smagina ZV, Novikov AV. Tuning the Luminescence Response of an Air-Hole Photonic Crystal Slab Using Etching Depth Variation. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13101678. [PMID: 37242094 DOI: 10.3390/nano13101678] [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: 04/19/2023] [Revised: 05/06/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023]
Abstract
Detailed studies of the luminescent properties of the Si-based 2D photonic crystal (PhC) slabs with air holes of various depths are reported. Ge self-assembled quantum dots served as an internal light source. It was obtained that changing the air hole depth is a powerful tool which allows tuning of the optical properties of the PhC. It was shown that increasing the depth of the holes in the PhC has complex influences on its overall photoluminescence (PL) response due to the simultaneous influences of counteracting factors. As a result, the maximal increase in the PL signal of more than two orders of magnitude was obtained for some intermediate, but not full, depth of the PhC's air holes. It was demonstrated that it is possible to engineer the PhC band structure in such a way as to construct specific states, namely bound states in continuum (BIC), with specially designed dispersion curves being relatively flat. In this case, such states manifest themselves as sharp peaks in the PL spectra, and have high Q-factors which are larger than those of radiative modes and other BIC modes without such a flat dispersion characteristic.
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Affiliation(s)
- Artem V Peretokin
- Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Dmitry V Yurasov
- Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Margarita V Stepikhova
- Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Mikhail V Shaleev
- Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Artem N Yablonskiy
- Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Dmitry V Shengurov
- Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
| | - Sergey A Dyakov
- Skolkovo Institute of Science and Technology, 143026 Moscow, 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
| | - Zhanna V Smagina
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Alexey V Novikov
- Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia
- Radiophysical Department, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
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4
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Poempool T, Aberl J, Clementi M, Spindlberger L, Vukušić L, Galli M, Gerace D, Fournel F, Hartmann JM, Schäffler F, Brehm M, Fromherz T. Single SiGe quantum dot emission deterministically enhanced in a high-Q photonic crystal resonator. OPTICS EXPRESS 2023; 31:15564-15578. [PMID: 37157655 DOI: 10.1364/oe.480281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We report the resonantly enhanced radiative emission from a single SiGe quantum dot (QD), which is deterministically embedded into a bichromatic photonic crystal resonator (PhCR) at the position of its largest modal electric field by a scalable method. By optimizing our molecular beam epitaxy (MBE) growth technique, we were able to reduce the amount of Ge within the whole resonator to obtain an absolute minimum of exactly one QD, accurately positioned by lithographic methods relative to the PhCR, and an otherwise flat, a few monolayer thin, Ge wetting layer (WL). With this method, record quality (Q) factors for QD-loaded PhCRs up to Q ∼ 105 are achieved. A comparison with control PhCRs on samples containing a WL but no QDs is presented, as well as a detailed analysis of the dependence of the resonator-coupled emission on temperature, excitation intensity, and emission decay after pulsed excitation. Our findings undoubtedly confirm a single QD in the center of the resonator as a potentially novel photon source in the telecom spectral range.
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Nawwar MA, Abo Ghazala MS, Sharaf El-Deen LM, Kashyout AEHB. Impact of strain engineering and Sn content on GeSn heterostructured nanomaterials for nanoelectronics and photonic devices. RSC Adv 2022; 12:24518-24554. [PMID: 36128382 PMCID: PMC9426448 DOI: 10.1039/d2ra04181b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/06/2022] [Indexed: 12/28/2022] Open
Abstract
Heterostructures based on the GeSn nanocompound have high impact on integrated photonics devices. The promising feature of GeSn nanostructures is its direct bandgap transition that is a result of Sn incorporation in the Ge networks, forming a strained structure. Herein, we demonstrate a deep survey of the strain-controlling mechanisms in GeSn nanomaterials with different methodologies. Using either layer configurations, Sn incorporation, or by external stressors, the emission of different photonic and nanoelectronic applications is controlled. We find that strain engineering modulates the bandgap of GeSn active media to control the region of emission for light emitting diodes, lasing applications, and spectral response for photodetection applications within the mid-IR region of the spectrum and enhances the performance of MOSFETs. This gives GeSn nanocompounds the chance to contribute greatly to IoT physical devices and compete with unstable perovskite materials since GeSn materials can achieve a stable and more reliable performance.
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Affiliation(s)
- Mohamed A Nawwar
- Physics Department, Faculty of Science, Menoufia University Shebin El-Koom Menoufia Egypt
| | - Magdy S Abo Ghazala
- Physics Department, Faculty of Science, Menoufia University Shebin El-Koom Menoufia Egypt
| | - Lobna M Sharaf El-Deen
- Physics Department, Faculty of Science, Menoufia University Shebin El-Koom Menoufia Egypt
| | - Abd El-Hady B Kashyout
- Electronic Materials Department, Advanced Technology and New Materials Research Institute, City of Scientific Research and Technological Applications (SRTA-City) New Borg El-Arab City Alexandria Egypt
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6
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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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7
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Dirko VV, Lozovoy KA, Kokhanenko AP, Voitsekhovskii AV. High-resolution RHEED analysis of dynamics of low-temperature superstructure transitions in Ge/Si(001) epitaxial system. NANOTECHNOLOGY 2021; 33:115603. [PMID: 34935639 DOI: 10.1088/1361-6528/ac3f56] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
In this paper, we analyze superstructural transitions during epitaxial growth of two-dimensional layers and the formation of quantum dots by the Stranski-Krastanov mechanism in elastically stressed systems by the reflection high-energy electron diffraction method. Detailed dependences of the periodicity parameterNof the 2 × Nreconstruction on the effective thickness of the deposited material in a wide range of growth temperatures during epitaxy of germanium on a silicon surface with a crystallographic orientation (001) are obtained. Superstructural transitions and the change in the value of the parameterNat low temperatures of epitaxy in this system have been investigated for the first time. It is shown that the length of dimer rows in such a reconstruction during the growth of pure germanium on silicon can reach a value of no less thanN = 11. A relationship is found between the value of the parameterN, determined by elastic strains in the system, and the critical thickness of the transition from two-dimensional to three-dimensional growth. Based on this relationship, a physical mechanism is proposed that explains the nature of the temperature dependence of the critical thickness of the Stranski-Krastanov transition, which has been the subject of constant scientific disputes until now.
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Affiliation(s)
- Vladimir V Dirko
- National Research Tomsk State University, Department of Radiophysics, 36 Lenin av., Tomsk 634050, Russia
| | - Kirill A Lozovoy
- National Research Tomsk State University, Department of Radiophysics, 36 Lenin av., Tomsk 634050, Russia
| | - Andrey P Kokhanenko
- National Research Tomsk State University, Department of Radiophysics, 36 Lenin av., Tomsk 634050, Russia
| | - Alexander V Voitsekhovskii
- National Research Tomsk State University, Department of Radiophysics, 36 Lenin av., Tomsk 634050, Russia
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8
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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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9
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Kamaliya B, Garg V, Liu ACY, Chen YE, Aslam M, Fu J, Mote RG. Tailoring Surface Self-Organization for Nanoscale Polygonal Morphology on Germanium. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008668. [PMID: 33837605 DOI: 10.1002/adma.202008668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/03/2021] [Indexed: 06/12/2023]
Abstract
The evolution of polygonal-shaped nanoholes on the (100) surface of germanium, aided by focused ion beam induced self-organization, is presented. The energetic beam of ions creates a viscous phase which, at a thermodynamical minimum, leads to surface self-organization. A directed viscous-flow along the predefined nanoholes provides well-ordered polygonal nanostructures, ranging from triangles to hexagons and octagons, as desired. The amorphization exhibiting a confined viscous-flow at the walls of nanoholes is attributed to the localized melting zones induced by site-specific thermal spikes during ion irradiation, as revealed by microscopy and molecular dynamics studies. This leads to a local self-organization in the vicinity of each circular nanohole via a viscous-fingering process at the nanoscale. Such controlled self-organization, with the help of a predefined scanning grid, transforms the circular holes into the desired polygonal shape. The present morphology manipulation promises to surmount the barriers concerning the size reduction efforts in the field of nanofabrication.
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Affiliation(s)
- Bhaveshkumar Kamaliya
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
- Department of Mechanical and Aerospace Engineering, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
| | - Vivek Garg
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
- Department of Mechanical and Aerospace Engineering, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
| | - Amelia C Y Liu
- School of Physics and Astronomy, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
- Monash Centre for Electron Microscopy, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
| | - Yu Emily Chen
- Monash Centre for Electron Microscopy, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
| | - Mohammed Aslam
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
| | - Jing Fu
- Department of Mechanical and Aerospace Engineering, Monash University, Wellington Road, Clayton, Victoria, 3800, Australia
| | - Rakesh G Mote
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076, India
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Zhang N, Chen P, Peng K, Zhang L, Liu T, Yan J, Jiang Z, Zhong Z. Promising modulation of self-assembled Ge-rich QDs by ultra-heavy phosphorus doping. NANOSCALE 2020; 12:13137-13144. [PMID: 32584338 DOI: 10.1039/d0nr00411a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Self-assembled Ge-rich quantum dots (QDs) can not only act as a prototype model for the fundamental studies of heteroepitaxial growth but also have great potential in optoelectronic devices for telecommunication and monolithic optical-electronic integrated circuits. Here, we report the unique features of Ge-rich QDs ultra-heavily doped with phosphorus (P) and embedded in a thin SiGe alloy film on Si (001) substrates. The ultra-heavy P doping considerably reduces the size of Ge-rich QDs and improves their uniformity. The inherent mechanism is associated with the reductions of both surface energy and the diffusion length of adatoms during QD growth promoted by the P dopants. Raman spectra indicate that the Ge content and strain in QDs are essentially not modified by the P doping. Particularly, the power- and temperature-dependent photoluminescence (PL) spectra demonstrate a type-I band alignment of Ge-rich QDs/SiGe alloy film due to the ultra-heavy P doping, which gives rise to additional low energy levels of electrons in QDs. Moreover, the PL of Ge-rich QDs is remarkably enhanced by ultra-heavy P doping at temperatures over 80 K. Over 3 times enhancement is obtained at 245 K. These results indicate that the overall quantum efficiency of Ge-rich QDs is substantially improved by the ultra-heavy P doping, which facilitates the applications of Ge-rich QDs in Si-based innovative optoelectronic devices.
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Affiliation(s)
- Ningning Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, People's Republic of China.
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11
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Photoluminescence of compact GeSi quantum dot groups with increased probability of finding an electron in Ge. Sci Rep 2020; 10:9308. [PMID: 32518243 PMCID: PMC7283240 DOI: 10.1038/s41598-020-64098-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 04/08/2020] [Indexed: 11/08/2022] Open
Abstract
The photoluminescence (PL) of the combined Ge/Si structures representing a combination of large (200–250 nm) GeSi disk-like quantum dots (nanodisks) and four-layered stacks of compact groups of smaller (30 nm) quantum dots grown in the strain field of nanodisks was studied. The multiple increase in the PL intensity was achieved by the variation of parameters of vertically aligned quantum dot groups. The experimental results were analyzed on the basis of calculations of energy spectra, electron and hole wave functions. It was found that the quantum dot arrangement in compact groups provides the effective electron localization in Δx,y-valleys with an almost equal probability of finding an electron in the Si spacer and Ge barrier. As a result, the main channels of radiative recombination in the structures under study correspond to spatially direct optical transitions.
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12
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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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13
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Dislocation Analysis in SiGe Heterostructures by Large-Angle Convergent Beam Electron Diffraction. CRYSTALS 2019. [DOI: 10.3390/cryst10010005] [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
Dislocations play a crucial role in self-organization and strain relaxation mechanisms in SiGe heterostructures. In most cases, they should be avoided, and different strategies exist to exploit their nucleation properties in order to manipulate their position. In either case, detailed knowledge about their exact Burgers vectors and possible dislocation reactions are necessary to optimize the fabrication processes and the properties of SiGe materials. In this review a brief overview of the dislocation mechanisms in the SiGe system is given. The method of choice for dislocation characterization is transmission electron microscopy. In particular, the article provides a detailed introduction into large-angle convergent-beam electron diffraction, and gives an overview of different application examples of this method on SiGe structures and related systems.
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14
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Aberl J, Brehm M, Fromherz T, Schuster J, Frigerio J, Rauter P. SiGe quantum well infrared photodetectors on strained-silicon-on-insulator. OPTICS EXPRESS 2019; 27:32009-32018. [PMID: 31684421 DOI: 10.1364/oe.27.032009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate p-type SiGe quantum well infrared photodetectors (QWIPs) on a strained-silicon-on-insulator (sSOI) substrate. The sSOI system allows strain-balancing between the QWIP heterostructure with an average composition of Si0.7Ge0.3 and the substrate, and therefore lifts restrictions to the active material thickness faced by SiGe growth on silicon or silicon-on-insulator substrates. The realized sSOI QWIPs feature a responsivity peak at detection wavelengths around 6 µm, based on a transition between heavy-hole states. The fabricated devices have been thoroughly characterized and compared to equivalent material simultaneously grown on virtual Si0.7Ge0.3 substrates based on graded SiGe buffers. Responsivities of up to 3.6 mA/W are achieved by the sSOI QWIPs at 77 K, demonstrating the large potential of sSOI-based devices as components for a group-IV optoelectronic platform in the mid-infrared spectral region.
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15
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Interdiffusion in group IV semiconductor material systems: applications, research methods and discoveries. Sci Bull (Beijing) 2019; 64:1436-1455. [PMID: 36659702 DOI: 10.1016/j.scib.2019.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 01/21/2023]
Abstract
Group IV semiconductor alloys and heterostructures such as SiGe, GeSn, Ge/Si and SiGe:C have been widely used and under extensive research for applications in major microelectronic and photonic devices. In the growth and processing of these materials, nanometer scale interdiffusion is common, which is generally undesirable for device performance. With higher Ge molar fractions and higher compressive strains, Si-Ge interdiffusion can be much faster than dopant diffusion. However, Si-Ge interdiffusion behaviors have not been well understood until recent years. Much less studies are available for GeSn. This review starts with basic properties and the applications of major group IV semiconductors, and then reviews the progress made so far on Si-Ge and Ge-Sn interdiffusion behaviors. Theories, experimental methods, design and practical considerations are discussed together with the key findings in this field.
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16
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Glassner S, Keshmiri H, Hill DJ, Cahoon JF, Fernandez B, den Hertog MI, Lugstein A. Tuning Electroluminescence from a Plasmonic Cavity-Coupled Silicon Light Source. NANO LETTERS 2018; 18:7230-7237. [PMID: 30335400 DOI: 10.1021/acs.nanolett.8b03391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The combination of Moore's law and Dennard's scaling rules have constituted the fundamental guidelines for the silicon-based semiconductor industry for decades. Furthermore, the enormous growth of global data volume has pushed the demand for complex and densely packed devices. In recent years, it has become clear that wired interconnects impose increasingly severe speed and power limitations onto integrated circuits as scaling slows toward a halt. To overcome these limitations, there is a clear need for optical data processing. Despite significant progress in the development of silicon photonics, light sources remain challenging owing to the indirect bandgap of group IV materials. It is therefore highly desirable to develop new concepts for a silicon light source that meets efficiency and footprint requirements similar to their electronic counterparts. Here, we demonstrate an electrically driven and tunable silicon light source by matching the resonant modes of a silver nanocavity with the hot luminescence spectrum of an avalanching p-n junction. The cavity significantly enhances phonon-assisted recombination of hot carriers by tailoring the local density of states at the size-tunable resonance. Such tunable nanoscale emitter may be of great interest for short-reach communications, microdisplays or lab-on-chip applications.
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Affiliation(s)
- S Glassner
- Institute of Solid State Electronics , TU Wien , Gußhausstraße 25-25a , 1040 Vienna , Austria
| | - H Keshmiri
- Institute of Solid State Electronics , TU Wien , Gußhausstraße 25-25a , 1040 Vienna , Austria
- Vienna Biocenter Core Facilities GmbH , Dr. Bohr-Gasse 3 , 1030 Vienna , Austria
| | - D J Hill
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599-3290 , United States
| | - J F Cahoon
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599-3290 , United States
| | - B Fernandez
- Institut NEEL CNRS/UGA UPR2940 , 25 avenue des Martyrs , 38042 Grenoble , France
| | - M I den Hertog
- Institut NEEL CNRS/UGA UPR2940 , 25 avenue des Martyrs , 38042 Grenoble , France
| | - A Lugstein
- Institute of Solid State Electronics , TU Wien , Gußhausstraße 25-25a , 1040 Vienna , Austria
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17
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Wang S, Zhang N, Chen P, Wang L, Yang X, Jiang Z, Zhong Z. Toward precise site-controlling of self-assembled Ge quantum dots on Si microdisks. NANOTECHNOLOGY 2018; 29:345606. [PMID: 29863488 DOI: 10.1088/1361-6528/aac9f6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A feasible route is developed toward precise site-controlling of quantum dots (QDs) at the microdisk periphery, where most microdisk cavity modes are located. The preferential growth of self-assembled Ge QDs at the periphery of Si microdisks is discovered. Moreover, both the height and linear density of Ge QDs can be controlled by tuning the amount of deposited Ge and the microdisk size. The inherent mechanisms of these unique features are discussed, taking into account both the growth kinetics and thermodynamics. By growing Ge on the innovative Si microdisks with small protrusions at the disk periphery, the positioning of Ge QDs at the periphery can be exactly predetermined. Such a precise site-controlling of Ge QDs at the periphery enables the location of the QD right at the field antinodes of the cavity mode of the Si microdisk, thereby achieving spatial matching between QD and cavity mode. These results open a promising door to realize the semiconductor QD-microdisk systems with both spectral and spatial matching between QDs and microdisk cavity modes, which will be the promising candidates for exploring the fundamental features of cavity quantum electrodynamics and the innovative optoelectronic devices based on strong light-matter interaction.
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Affiliation(s)
- Shuguang Wang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, People's Republic of China. Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People's Republic of China
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18
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Lepadatu AM, Slav A, Palade C, Dascalescu I, Enculescu M, Iftimie S, Lazanu S, Teodorescu VS, Ciurea ML, Stoica T. Dense Ge nanocrystals embedded in TiO 2 with exponentially increased photoconduction by field effect. Sci Rep 2018; 8:4898. [PMID: 29559710 PMCID: PMC5861074 DOI: 10.1038/s41598-018-23316-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/06/2018] [Indexed: 01/21/2023] Open
Abstract
Si and Ge nanocrystals in oxides are of a large interest for photo-effect applications due to the fine-tuning of the optical bandgap by quantum confinement in nanocrystals. In this work, dense Ge nanocrystals suitable for enhanced photoconduction were fabricated from 60% Ge in TiO2 amorphous layers by low temperature rapid thermal annealing at 550 °C. An exponential increase of the photocurrent with the applied voltage was observed in coplanar structure of Ge nanocrystals composite films deposited on oxidized Si wafers. The behaviour was explained by field effect control of the Fermi level at the Ge nanocrystals-TiO2 layer/substrate interfaces. The blue-shift of the absorption gap from bulk Ge value to 1.14 eV was evidenced in both photocurrent spectra and optical reflection-transmission experiments, in good agreement with quantum confinement induced bandgap broadening in Ge nanocrystal with sizes of about 5 nm as found from HRTEM and XRD investigations. A nonmonotonic spectral dependence of the refractive index is associated to the Ge nanocrystals formation. The nanocrystal morphology is also in good agreement with the Coulomb gap hopping mechanism of T-1/2 -type explaining the temperature dependence of the dark conduction.
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Affiliation(s)
- A-M Lepadatu
- National Institute of Materials Physics, 077125, Magurele, Romania
| | - A Slav
- National Institute of Materials Physics, 077125, Magurele, Romania
| | - C Palade
- National Institute of Materials Physics, 077125, Magurele, Romania
| | - I Dascalescu
- National Institute of Materials Physics, 077125, Magurele, Romania
| | - M Enculescu
- National Institute of Materials Physics, 077125, Magurele, Romania
| | - S Iftimie
- University of Bucharest, Faculty of Physics, 077125, Magurele, Romania
| | - S Lazanu
- National Institute of Materials Physics, 077125, Magurele, Romania
| | - V S Teodorescu
- National Institute of Materials Physics, 077125, Magurele, Romania
| | - M L Ciurea
- National Institute of Materials Physics, 077125, Magurele, Romania. .,Academy of Romanian Scientists, 050094, Bucharest, Romania.
| | - T Stoica
- National Institute of Materials Physics, 077125, Magurele, Romania.
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19
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Yamamoto Y, Zaumseil P, Capellini G, Andreas Schubert M, Hesse A, Albani M, Bergamaschini R, Montalenti F, Schroeder T, Tillack B. A self-ordered, body-centered tetragonal superlattice of SiGe nanodot growth by reduced pressure CVD. NANOTECHNOLOGY 2017; 28:485303. [PMID: 28985186 DOI: 10.1088/1361-6528/aa91c1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Self-ordered three-dimensional body-centered tetragonal (BCT) SiGe nanodot structures are fabricated by depositing SiGe/Si superlattice layer stacks using reduced pressure chemical vapor deposition. For high enough Ge content in the island (>30%) and deposition temperature of the Si spacer layers (T > 700 °C), we observe the formation of an ordered array with islands arranged in staggered position in adjacent layers. The in plane periodicity of the islands can be selected by a suitable choice of the annealing temperature before the Si spacer layer growth and of the SiGe dot volume, while only a weak influence of the Ge concentration is observed. Phase-field simulations are used to clarify the driving force determining the observed BCT ordering, shedding light on the competition between heteroepitaxial strain and surface-energy minimization in the presence of a non-negligible surface roughness.
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Affiliation(s)
- Yuji Yamamoto
- IHP, Im Technologiepark, 25, D-15236 Frankfurt (Oder), Germany
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20
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Free-running Sn precipitates: an efficient phase separation mechanism for metastable Ge 1-xSn x epilayers. Sci Rep 2017; 7:16114. [PMID: 29170483 PMCID: PMC5700949 DOI: 10.1038/s41598-017-16356-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 11/10/2017] [Indexed: 11/08/2022] Open
Abstract
The revival of interest in Ge1−xSnx alloys with x ≥ 10% is mainly owed to the recent demonstration of optical gain in this group-IV heterosystem. Yet, Ge and Sn are immiscible over about 98% of the composition range, which renders epilayers based on this material system inherently metastable. Here, we address the temperature stability of pseudomorphic Ge1−xSnx films grown by molecular beam epitaxy. Both the growth temperature dependence and the influence of post-growth annealing steps were investigated. In either case we observe that the decomposition of epilayers with Sn concentrations of around 10% sets in above ≈230 °C, the eutectic temperature of the Ge/Sn system. Time-resolved in-situ annealing experiments in a scanning electron microscope reveal the crucial role of liquid Sn precipitates in this phase separation process. Driven by a gradient of the chemical potential, the Sn droplets move on the surface along preferential crystallographic directions, thereby taking up Sn and Ge from the strained Ge1−xSnx layer. While Sn-uptake increases the volume of the melt, single-crystalline Ge becomes re-deposited by a liquid-phase epitaxial process at the trailing edge of the droplet. This process makes phase separation of metastable GeSn layers particularly efficient at rather low temperatures.
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21
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Brehm M, Grydlik M. Site-controlled and advanced epitaxial Ge/Si quantum dots: fabrication, properties, and applications. NANOTECHNOLOGY 2017; 28:392001. [PMID: 28729522 DOI: 10.1088/1361-6528/aa8143] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this review, we report on fabrication paths, challenges, and emerging solutions to integrate group-IV epitaxial quantum dots (QDs) as active light emitters into the existing standard Si technology. Their potential as laser gain material for the use of optical intra- and inter-chip interconnects as well as possibilities to combine a single-photon-source-based quantum cryptographic means with Si technology will be discussed. We propose that the mandatory addressability of the light emitters can be achieved by a combination of organized QD growth assisted by templated self-assembly, and advanced inter-QD defect engineering to boost the optical emissivity of group-IV QDs at room-temperature. Those two main parts, the site-controlled growth and the light emission enhancement in QDs through the introduction of single defects build the main body of the review. This leads us to a roadmap for the necessary further development of this emerging field of CMOS-compatible group-IV QD light emitters for on-chip applications.
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22
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Bar R, Katiyar AK, Aluguri R, Ray SK. Emission characteristics of self-assembled strained Ge 1-xSn x islands for sources in the optical communication region. NANOTECHNOLOGY 2017; 28:295201. [PMID: 28475108 DOI: 10.1088/1361-6528/aa715e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Self-assembled strained Ge1-x Sn x islands on Si (100) have been grown at a low temperature using molecular beam epitaxy. The in-built strain and fraction of Sn in the islands have been estimated using x-ray photoelectron spectroscopy and high resolution x-ray diffraction study of grown samples. No-phonon assisted transition in the optical communication wavelength range of 1.4-1.8 μm has been observed in the Ge1-x Sn x island samples. The direct band gap transition intensity is found to increase with a growth in Sn concentration, with this increase in intensity sustained up to a temperature of 130 K in Ge1-x Sn x islands. The observed electroluminescence in p-i-n devices fabricated on Ge1-x Sn x island samples above a threshold bias of 4 V makes them attractive for future Si based optical devices.
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Affiliation(s)
- Rajshekhar Bar
- Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur-721302, India
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23
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Schatzl M, Hackl F, Glaser M, Rauter P, Brehm M, Spindlberger L, Simbula A, Galli M, Fromherz T, Schäffler F. Enhanced Telecom Emission from Single Group-IV Quantum Dots by Precise CMOS-Compatible Positioning in Photonic Crystal Cavities. ACS PHOTONICS 2017; 4:665-673. [PMID: 28345012 PMCID: PMC5355891 DOI: 10.1021/acsphotonics.6b01045] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Indexed: 05/25/2023]
Abstract
Efficient coupling to integrated high-quality-factor cavities is crucial for the employment of germanium quantum dot (QD) emitters in future monolithic silicon-based optoelectronic platforms. We report on strongly enhanced emission from single Ge QDs into L3 photonic crystal resonator (PCR) modes based on precise positioning of these dots at the maximum of the respective mode field energy density. Perfect site control of Ge QDs grown on prepatterned silicon-on-insulator substrates was exploited to fabricate in one processing run almost 300 PCRs containing single QDs in systematically varying positions within the cavities. Extensive photoluminescence studies on this cavity chip enable a direct evaluation of the position-dependent coupling efficiency between single dots and selected cavity modes. The experimental results demonstrate the great potential of the approach allowing CMOS-compatible parallel fabrication of arrays of spatially matched dot/cavity systems for group-IV-based data transfer or quantum optical systems in the telecom regime.
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Affiliation(s)
- Magdalena Schatzl
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Florian Hackl
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Martin Glaser
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Patrick Rauter
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Moritz Brehm
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Lukas Spindlberger
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Angelica Simbula
- Dipartimento
di Fisica, Università degli Studi
di Pavia, Via A. Bassi 6, 27100 Pavia, Italy
| | - Matteo Galli
- Dipartimento
di Fisica, Università degli Studi
di Pavia, Via A. Bassi 6, 27100 Pavia, Italy
| | - Thomas Fromherz
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Friedrich Schäffler
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
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24
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Grydlik M, Lusk MT, Hackl F, Polimeni A, Fromherz T, Jantsch W, Schäffler F, Brehm M. Laser Level Scheme of Self-Interstitials in Epitaxial Ge Dots Encapsulated in Si. NANO LETTERS 2016; 16:6802-6807. [PMID: 27701863 PMCID: PMC5108030 DOI: 10.1021/acs.nanolett.6b02494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/22/2016] [Indexed: 05/25/2023]
Abstract
Recently, it was shown that lasing from epitaxial Ge quantum dots (QDs) on Si substrates can be obtained if they are partially amorphized by Ge ion bombardment (GIB). Here, we present a model for the microscopic origin of the radiative transitions leading to enhanced photoluminescence (PL) from such GIB-QDs. We provide an energy level scheme for GIB-QDs in a crystalline Si matrix that is based on atomistic modeling with Monte Carlo (MC) analysis and density functional theory (DFT). The level scheme is consistent with a broad variety of PL experiments performed on as-grown and annealed GIB-QDs. Our results show that an extended point defect consisting of a split-[110] self-interstitial surrounded by a distorted crystal lattice of about 45 atoms leads to electronic states at the Γ-point of the Brillouin zone well below the conduction band minimum of crystalline Ge. Such defects in Ge QDs allow direct transitions of electrons localized at the split-interstitial with holes confined in the Ge QD. We identify the relevant growth and annealing parameters that will let GIB-QDs be employed as an efficient laser active medium.
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Affiliation(s)
- Martyna Grydlik
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenberger
Strasse 69, A-4040 Linz, Austria
| | - Mark T. Lusk
- Department of Physics, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Florian Hackl
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenberger
Strasse 69, A-4040 Linz, Austria
| | - Antonio Polimeni
- CNISM and
Department of Physics, Sapienza Università
di Roma, Piazzale A.
Moro 2, 00185 Roma, Italy
| | - Thomas Fromherz
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenberger
Strasse 69, A-4040 Linz, Austria
| | - Wolfgang Jantsch
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenberger
Strasse 69, A-4040 Linz, Austria
| | - Friedrich Schäffler
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenberger
Strasse 69, A-4040 Linz, Austria
| | - Moritz Brehm
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University Linz, Altenberger
Strasse 69, A-4040 Linz, Austria
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25
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Guillous S, Bourin C, Ban D'Etat B, Benyagoub A, Cassimi A, Feierstein C, Gardés E, Giglio E, Girard S, Grygiel C, Houel A, Lebius H, Méry A, Monnet I, Ramillon JM, Rangama J, Ropars F, Verzeroli E, Viteau M, Delobbe A. A new setup for localized implantation and live-characterization of keV energy multiply charged ions at the nanoscale. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:113901. [PMID: 27910696 DOI: 10.1063/1.4966675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An innovative experimental setup, PELIICAEN, allowing the modification of materials and the study of the effects induced by multiply charged ion beams at the nanoscale is presented. This ultra-high vacuum (below 5 × 10-10 mbar) apparatus is equipped with a focused ion beam column using multiply charged ions and a scanning electron microscope developed by Orsay Physics, as well as a scanning probe microscope. The dual beam approach coupled to the scanning probe microscope achieves nanometer scale in situ topological analysis of the surface modifications induced by the ion beams. Preliminary results using the different on-line characterization techniques to study the formation of nano-hillocks on silicon and mica substrates are presented to illustrate the performances of the setup.
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Affiliation(s)
- S Guillous
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - C Bourin
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - B Ban D'Etat
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - A Benyagoub
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - A Cassimi
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - C Feierstein
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - E Gardés
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - E Giglio
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - S Girard
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - C Grygiel
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - A Houel
- Orsay Physics (Tescan-Orsay Holding), 95 Avenue des Monts Auréliens, ZA Saint-Charles F-13710, Fuveau, France
| | - H Lebius
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - A Méry
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - I Monnet
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - J-M Ramillon
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - J Rangama
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - F Ropars
- CIMAP (CEA, CNRS, ENSICAEN, UNICAEN, Normandie University), Boulevard Henri Becquerel, BP 5133, Caen 14070 Cedex 5, France
| | - E Verzeroli
- Orsay Physics (Tescan-Orsay Holding), 95 Avenue des Monts Auréliens, ZA Saint-Charles F-13710, Fuveau, France
| | - M Viteau
- Orsay Physics (Tescan-Orsay Holding), 95 Avenue des Monts Auréliens, ZA Saint-Charles F-13710, Fuveau, France
| | - A Delobbe
- Orsay Physics (Tescan-Orsay Holding), 95 Avenue des Monts Auréliens, ZA Saint-Charles F-13710, Fuveau, France
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26
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Naffouti M, David T, Benkouider A, Favre L, Cabie M, Ronda A, Berbezier I, Abbarchi M. Fabrication of core-shell nanostructures via silicon on insulator dewetting and germanium condensation: towards a strain tuning method for SiGe-based heterostructures in a three-dimensional geometry. NANOTECHNOLOGY 2016; 27:305602. [PMID: 27302611 DOI: 10.1088/0957-4484/27/30/305602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on a novel method for the implementation of core-shell SiGe-based nanocrystals combining silicon on insulator dewetting in a molecular beam epitaxy reactor with an ex situ Ge condensation process. With an in situ two-step process (annealing and Ge deposition) we produce two families of islands on the same sample: Si-rich, formed during the first step and, all around them, Ge-rich formed after Ge deposition. By increasing the amount of Ge deposited on the annealed samples from 0 to 18 monolayers, the islands' shape in the Si-rich zones can be tuned from elongated and flat to more symmetric and with a larger vertical aspect ratio. At the same time, the spatial extension of the Ge-rich zones is progressively increased as well as the Ge content in the islands. Further processing by ex situ rapid thermal oxidation results in the formation of a core-shell composition profile in both Si and Ge-rich zones with atomically sharp heterointerfaces. The Ge condensation induces a Ge enrichment of the islands' shell of up to 50% while keeping a pure Si core in the Si-rich zones and a ∼25% SiGe alloy in the Ge-rich ones. The large lattice mismatch between core and shell, the absence of dislocations and the islands' monocrystalline nature render this novel class of nanostructures a promising device platform for strain-based band-gap engineering. Finally, this method can be used for the implementation of ultralarge scale meta-surfaces with dielectric Mie resonators for light manipulation at the nanoscale.
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Affiliation(s)
- Meher Naffouti
- Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 13397, Marseille, France. Laboratoire de Micro-optoélectronique et Nanostructures, Faculté des Sciences de Monastir, Université de Monastir 5019 Monastir, Tunisia
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