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Kim Y, Assali S, Joo HJ, Koelling S, Chen M, Luo L, Shi X, Burt D, Ikonic Z, Nam D, Moutanabbir O. Short-wave infrared cavity resonances in a single GeSn nanowire. Nat Commun 2023; 14:4393. [PMID: 37474549 PMCID: PMC10359335 DOI: 10.1038/s41467-023-40140-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 07/03/2023] [Indexed: 07/22/2023] Open
Abstract
Nanowires are promising platforms for realizing ultra-compact light sources for photonic integrated circuits. In contrast to impressive progress on light confinement and stimulated emission in III-V and II-VI semiconductor nanowires, there has been no experimental demonstration showing the potential to achieve strong cavity effects in a bottom-up grown single group-IV nanowire, which is a prerequisite for realizing silicon-compatible infrared nanolasers. Herein, we address this limitation and present an experimental observation of cavity-enhanced strong photoluminescence from a single Ge/GeSn core/shell nanowire. A sufficiently large Sn content ( ~ 10 at%) in the GeSn shell leads to a direct bandgap gain medium, allowing a strong reduction in material loss upon optical pumping. Efficient optical confinement in a single nanowire enables many round trips of emitted photons between two facets of a nanowire, achieving a narrow width of 3.3 nm. Our demonstration opens new possibilities for ultrasmall on-chip light sources towards realizing photonic-integrated circuits in the underexplored range of short-wave infrared (SWIR).
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Affiliation(s)
- Youngmin Kim
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Simone Assali
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, QC, H3C 3A7, Canada
| | - Hyo-Jun Joo
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Sebastian Koelling
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, QC, H3C 3A7, Canada
| | - Melvina Chen
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Lu Luo
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, QC, H3C 3A7, Canada
| | - Xuncheng Shi
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Daniel Burt
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zoran Ikonic
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - Donguk Nam
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
| | - Oussama Moutanabbir
- Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, QC, H3C 3A7, Canada.
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2
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Direct-bandgap emission from hexagonal Ge and SiGe alloys. Nature 2020; 580:205-209. [PMID: 32269353 DOI: 10.1038/s41586-020-2150-y] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/11/2020] [Indexed: 12/24/2022]
Abstract
Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si), germanium (Ge) and SiGe alloys are all indirect-bandgap semiconductors that cannot emit light efficiently. The goal1 of achieving efficient light emission from group-IV materials in silicon technology has been elusive for decades2-6. Here we demonstrate efficient light emission from direct-bandgap hexagonal Ge and SiGe alloys. We measure a sub-nanosecond, temperature-insensitive radiative recombination lifetime and observe an emission yield similar to that of direct-bandgap group-III-V semiconductors. Moreover, we demonstrate that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned over a broad range, while preserving the direct bandgap. Our experimental findings are in excellent quantitative agreement with ab initio theory. Hexagonal SiGe embodies an ideal material system in which to combine electronic and optoelectronic functionalities on a single chip, opening the way towards integrated device concepts and information-processing technologies.
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Sinito C, Corfdir P, Pfüller C, Gao G, Bartolomé J, Kölling S, Rodil Doblado A, Jahn U, Lähnemann J, Auzelle T, Zettler JK, Flissikowski T, Koenraad P, Grahn HT, Geelhaar L, Fernández-Garrido S, Brandt O. Absence of Quantum-Confined Stark Effect in GaN Quantum Disks Embedded in (Al,Ga)N Nanowires Grown by Molecular Beam Epitaxy. NANO LETTERS 2019; 19:5938-5948. [PMID: 31385709 DOI: 10.1021/acs.nanolett.9b01521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Several of the key issues of planar (Al,Ga)N-based deep-ultraviolet light-emitting diodes could potentially be overcome by utilizing nanowire heterostructures, exhibiting high structural perfection, and improved light extraction. Here, we study the spontaneous emission of GaN/(Al,Ga)N nanowire ensembles grown on Si(111) by plasma-assisted molecular beam epitaxy. The nanowires contain single GaN quantum disks embedded in long (Al,Ga)N nanowire segments essential for efficient light extraction. These quantum disks are found to exhibit intense light emission at unexpectedly high energies, namely, significantly above the GaN bandgap, and almost independent of the disk thickness. An in-depth investigation of the actual structure and composition of the nanowires reveals a spontaneously formed Al gradient both along and across the nanowire, resulting in a complex core/shell structure with an Al-deficient core and an Al-rich shell with continuously varying Al content along the entire length of the (Al,Ga)N segment. This compositional change along the nanowire growth axis induces a polarization doping of the shell that results in a degenerate electron gas in the disk, thus screening the built-in electric fields. The high carrier density not only results in the unexpectedly high transition energies but also in radiative lifetimes depending only weakly on temperature, leading to a comparatively high internal quantum efficiency of the GaN quantum disks up to room temperature.
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Affiliation(s)
- C Sinito
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - P Corfdir
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - C Pfüller
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - G Gao
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J Bartolomé
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - S Kölling
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - A Rodil Doblado
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - U Jahn
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J Lähnemann
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - T Auzelle
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - J K Zettler
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - T Flissikowski
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - P Koenraad
- Department of Applied Physics , TU Eindhoven , Den Dolech 2 , 5612 Eindhoven , AZ , The Netherlands
| | - H T Grahn
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - L Geelhaar
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - S Fernández-Garrido
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - O Brandt
- Paul Drude Institut für Festkörperelektronik , Leibniz Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
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Lähnemann J, Hill MO, Herranz J, Marquardt O, Gao G, Al Hassan A, Davtyan A, Hruszkewycz SO, Holt MV, Huang C, Calvo-Almazán I, Jahn U, Pietsch U, Lauhon LJ, Geelhaar L. Correlated Nanoscale Analysis of the Emission from Wurtzite versus Zincblende (In,Ga)As/GaAs Nanowire Core-Shell Quantum Wells. NANO LETTERS 2019; 19:4448-4457. [PMID: 31141672 DOI: 10.1021/acs.nanolett.9b01241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
While the properties of wurtzite GaAs have been extensively studied during the past decade, little is known about the influence of the crystal polytype on ternary (In,Ga)As quantum well structures. We address this question with a unique combination of correlated, spatially resolved measurement techniques on core-shell nanowires that contain extended segments of both the zincblende and wurtzite polytypes. Cathodoluminescence hyperspectral imaging reveals a blue-shift of the quantum well emission energy by 75 ± 15 meV in the wurtzite polytype segment. Nanoprobe X-ray diffraction and atom probe tomography enable k·p calculations for the specific sample geometry to reveal two comparable contributions to this shift. First, there is a 30% drop in In mole fraction going from the zincblende to the wurtzite segment. Second, the quantum well is under compressive strain, which has a much stronger impact on the hole ground state in the wurtzite than in the zincblende segment. Our results highlight the role of the crystal structure in tuning the emission of (In,Ga)As quantum wells and pave the way to exploit the possibilities of three-dimensional band gap engineering in core-shell nanowire heterostructures. At the same time, we have demonstrated an advanced characterization toolkit for the investigation of semiconductor nanostructures.
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Affiliation(s)
- Jonas Lähnemann
- Paul-Drude-Institut für Festkörperelektronik , Leibniz-Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Megan O Hill
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Jesús Herranz
- Paul-Drude-Institut für Festkörperelektronik , Leibniz-Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Oliver Marquardt
- Weierstraß-Institut für Angewandte Analysis und Stochastik , Leibniz-Institut im Forschungsverbund Berlin e.V. , Mohrenstr. 39 , 10117 Berlin , Germany
| | - Guanhui Gao
- Paul-Drude-Institut für Festkörperelektronik , Leibniz-Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Ali Al Hassan
- Naturwissenschaftlich-Technische Fakultät der Universität Siegen , 57068 Siegen , Germany
| | - Arman Davtyan
- Naturwissenschaftlich-Technische Fakultät der Universität Siegen , 57068 Siegen , Germany
| | - Stephan O Hruszkewycz
- Materials Science Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Martin V Holt
- Center for Nanoscale Materials , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Chunyi Huang
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Irene Calvo-Almazán
- Materials Science Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Uwe Jahn
- Paul-Drude-Institut für Festkörperelektronik , Leibniz-Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
| | - Ullrich Pietsch
- Naturwissenschaftlich-Technische Fakultät der Universität Siegen , 57068 Siegen , Germany
| | - Lincoln J Lauhon
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Lutz Geelhaar
- Paul-Drude-Institut für Festkörperelektronik , Leibniz-Institut im Forschungsverbund Berlin e.V. , Hausvogteiplatz 5-7 , 10117 Berlin , Germany
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Siladie AM, Amichi L, Mollard N, Mouton I, Bonef B, Bougerol C, Grenier A, Robin E, Jouneau PH, Garro N, Cros A, Daudin B. Dopant radial inhomogeneity in Mg-doped GaN nanowires. NANOTECHNOLOGY 2018; 29:255706. [PMID: 29620532 DOI: 10.1088/1361-6528/aabbd6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Using atom probe tomography, it is demonstrated that Mg doping of GaN nanowires grown by Molecular Beam Epitaxy results in a marked radial inhomogeneity, namely a higher Mg content in the periphery of the nanowires. This spatial inhomogeneity is attributed to a preferential incorporation of Mg through the m-plane sidewalls of nanowires and is related to the formation of a Mg-rich surface which is stabilized by hydrogen. This is further supported by Raman spectroscopy experiments which give evidence of Mg-H complexes in the doped nanowires. A Mg doping mechanism such as this, specific to nanowires, may lead to higher levels of Mg doping than in layers, boosting the potential interest of nanowires for light emitting diode applications.
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6
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Melkonyan D, Fleischmann C, Veloso A, Franquet A, Bogdanowicz J, Morris RJH, Vandervorst W. Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures. Ultramicroscopy 2017; 186:1-8. [PMID: 29241145 DOI: 10.1016/j.ultramic.2017.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 11/30/2022]
Abstract
We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO2 we demonstrate how the selective removal of SiO2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively.
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Affiliation(s)
- D Melkonyan
- Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium; Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium.
| | | | - A Veloso
- Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium
| | - A Franquet
- Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium
| | | | | | - W Vandervorst
- Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium; Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium
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7
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Sun Z, Tzaguy A, Hazut O, Lauhon LJ, Yerushalmi R, Seidman DN. 1-D Metal Nanobead Arrays within Encapsulated Nanowires via a Red-Ox-Induced Dewetting: Mechanism Study by Atom-Probe Tomography. NANO LETTERS 2017; 17:7478-7486. [PMID: 29116798 DOI: 10.1021/acs.nanolett.7b03391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Metal nanoparticle arrays are excellent candidates for a variety of applications due to the versatility of their morphology and structure at the nanoscale. Bottom-up self-assembly of metal nanoparticles provides an important complementary alternative to the traditional top-down lithography method and makes it possible to assemble structures with higher-order complexity, for example, nanospheres, nanocubes, and core-shell nanostructures. Here we present a mechanism study of the self-assembly process of 1-D noble metal nanoparticles arrays, composed of Au, Ag, and AuAg alloy nanoparticles. These are prepared within an encapsulated germanium nanowire, obtained by the oxidation of a metal-germanium nanowire hybrid structure. The resulting structure is a 1-D array of equidistant metal nanoparticles with the same diameter, the so-called nanobead (NB) array structure. Atom-probe tomography and transmission electron microscopy were utilized to investigate the details of the morphological and chemical evolution during the oxidation of the encapsulated metal-germanium nanowire hybrid-structures. The self-assembly of nanoparticles relies on the formation of a metal-germanium liquid alloy and the migration of the liquid alloy into the nanowire, followed by dewetting of the liquid during shape-confined oxidation where the liquid column breaks-up into nanoparticles due to the Plateau-Rayleigh instability. Our results demonstrate that the encapsulating oxide layer serves as a structural scaffold, retaining the overall shape during the eutectic liquid formation and demonstrates the relationship between the oxide mechanical properties and the final structural characteristics of the 1-D arrays. The mechanistic details revealed here provide a versatile tool-box for the bottom-up fabrication of 1-D arrays nanopatterning that can be modified for multiple applications according to the RedOx properties of the material system components.
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Affiliation(s)
- Zhiyuan Sun
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Avra Tzaguy
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Ori Hazut
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Lincoln J Lauhon
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Roie Yerushalmi
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - David N Seidman
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
- Northwestern University Center for Atom-Probe Tomography (NUCAPT) , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
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8
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Systematic approaches for targeting an atom-probe tomography sample fabricated in a thin TEM specimen: Correlative structural, chemical and 3-D reconstruction analyses. Ultramicroscopy 2017; 184:284-292. [PMID: 29054043 DOI: 10.1016/j.ultramic.2017.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/06/2017] [Accepted: 10/10/2017] [Indexed: 11/21/2022]
Abstract
Atom-probe tomography (APT) is a unique analysis tool that enables true three-dimensional (3-D) analyses with sub-nano scale spatial resolution. Recent implementations of the local-electrode atom-probe (LEAP) tomograph with ultraviolet laser pulsing have significantly expanded the research applications of APT. The small field-of-view of a needle-shaped specimen with a less than 100 nm diam. is, however, a major limitation for analyzing materials. The systematic approaches for site-specific targeting of an APT nanotip in a transmission electron microscope (TEM) of a thin sample are introduced to solve the geometrical limitations of a sharpened APT nanotip. In addition to "coupling APT to TEM", the technique presented here allows for targeting the preparation of an APT tip based on TEM observation of a much larger area than what is captured in the APT tip. The correlative methods have synergies for not only high-resolution structural analyses but also for obtaining chemical information. Chemical analyses in a TEM, both energy-dispersive X-ray spectroscopy (EDS) and electron energy-loss spectroscopy (EELS), are performed and compared with the APT chemical analyses of a carbide phase (M7C3) precipitate at a grain boundary in a Ni-based alloy. Additionally, a TEM image of a sharpened APT nanotip is utilized for calculation of the detection area ratio of an APT nanotip by comparison with a TEM image for precise tomographic reconstructions. A grain-boundary/carbide precipitate triple junction is used to attain precise positioning of an APT nanotip in an analyzed TEM specimen.
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9
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Sun Z, Hazut O, Yerushalmi R, Lauhon LJ, Seidman DN. Criteria and considerations for preparing atom-probe tomography specimens of nanomaterials utilizing an encapsulation methodology. Ultramicroscopy 2017; 184:225-233. [PMID: 28985626 DOI: 10.1016/j.ultramic.2017.09.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/19/2017] [Accepted: 09/22/2017] [Indexed: 10/18/2022]
Abstract
Atom-probe tomography (APT) is a powerful method for characterization of nanomaterials due to its atomic-ppm level detection limit and Angstrom spatial resolution. Sample preparation for nanomaterials is, however, challenging because of their small dimensions and complicated geometries. Nanowires, with their high geometrical aspect ratio and nanowire length, 10 to 100 times their typical diameters, are highly suitable specimens for APT analyses, which can be transferred to silicon microposts using a nanomanipulator for direct APT measurements. This method is, however, prone to poor alignment and a limited field-of-view (FOV). Most importantly, direct implementation of APT with high aspect ratio nanowires may yield a low success rate of ∼30%, due to the high electric fields (10-40 V nm-1) associated with APT. While this is acceptable for samples analyzed solely by APT, a low sample yield makes it challenging to perform correlative experiments on the same nanowire specimen, utilizing other sophisticated characterization instruments. Herein, we introduce a general strategy for preparing high-yield APT specimens by encapsulating the nanowires utilizing a conformal atomic-layer deposition (ALD) coating followed by site-specific lift-out using a dual-beam focused-ion beam microscope. The ALD deposited coating forms strong chemical bonds with the Si nanowires yielding a high-quality and robust interface. The evaporation electric fields of the ALD coating and the nanowires are tuned by changing laser energy to obtain a uniform evaporation rate. The strong adhesion of the ALD-coating/nanowire interface and uniform evaporation rate produce a >90% specimen yield, with small concentration of reconstruction artifacts in 3-D. Simultaneously, the field-of-view is enhanced and the surface of the nanowire becomes visible, which makes the study of surface adsorption, segregation and oxidation possible. We utilized ALD-ZnO coated silicon nanowires as an example for investigating the criteria for choosing coating materials, laser pulse energy, laser direction, sample geometry, and substrate materials. The same criteria and considerations are applicable for preparing specimens of nanoparticles and 2-D material.
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Affiliation(s)
- Zhiyuan Sun
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208-3108, USA
| | - Ori Hazut
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Roie Yerushalmi
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Lincoln J Lauhon
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208-3108, USA.
| | - David N Seidman
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL 60208-3108, USA; Northwestern University Center for Atom-Probe Tomography (NUCAPT), 2220 Campus Drive, Evanston, IL 60208-3108, USA.
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10
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Parikh P, Senowitz C, Lyons D, Martin I, Prosa TJ, DiBattista M, Devaraj A, Meng YS. Three-Dimensional Nanoscale Mapping of State-of-the-Art Field-Effect Transistors (FinFETs). MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:916-925. [PMID: 28854989 DOI: 10.1017/s1431927617012491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The semiconductor industry has seen tremendous progress over the last few decades with continuous reduction in transistor size to improve device performance. Miniaturization of devices has led to changes in the dopants and dielectric layers incorporated. As the gradual shift from two-dimensional metal-oxide semiconductor field-effect transistor to three-dimensional (3D) field-effect transistors (finFETs) occurred, it has become imperative to understand compositional variability with nanoscale spatial resolution. Compositional changes can affect device performance primarily through fluctuations in threshold voltage and channel current density. Traditional techniques such as scanning electron microscope and focused ion beam no longer provide the required resolution to probe the physical structure and chemical composition of individual fins. Hence advanced multimodal characterization approaches are required to better understand electronic devices. Herein, we report the study of 14 nm commercial finFETs using atom probe tomography (APT) and scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (STEM-EDS). Complimentary compositional maps were obtained using both techniques with analysis of the gate dielectrics and silicon fin. APT additionally provided 3D information and allowed analysis of the distribution of low atomic number dopant elements (e.g., boron), which are elusive when using STEM-EDS.
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Affiliation(s)
- Pritesh Parikh
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Corey Senowitz
- Qualcomm Technologies, Inc., 5775 Morehouse Drive, San Diego, CA 92121, USA
| | - Don Lyons
- Qualcomm Technologies, Inc., 5775 Morehouse Drive, San Diego, CA 92121, USA
| | - Isabelle Martin
- CAMECA Instruments, Inc., 5500 Nobel Drive, Madison, WI 53711, USA
| | - Ty J Prosa
- CAMECA Instruments, Inc., 5500 Nobel Drive, Madison, WI 53711, USA
| | - Michael DiBattista
- Varioscale, Inc., 1782 La Costa Meadows Dr #103, San Marcos, CA 92078, USA
| | - Arun Devaraj
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA
| | - Y Shirley Meng
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Conductance through a helical state in an Indium antimonide nanowire. Nat Commun 2017; 8:478. [PMID: 28883423 PMCID: PMC5589903 DOI: 10.1038/s41467-017-00315-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/16/2017] [Indexed: 11/08/2022] Open
Abstract
The motion of an electron and its spin are generally not coupled. However in a one-dimensional material with strong spin-orbit interaction (SOI) a helical state may emerge at finite magnetic fields, where electrons of opposite spin will have opposite momentum. The existence of this helical state has applications for spin filtering and cooper pair splitter devices and is an essential ingredient for realizing topologically protected quantum computing using Majorana zero modes. Here, we report measurements of a quantum point contact in an indium antimonide nanowire. At magnetic fields exceeding 3 T, the 2 e2/h conductance plateau shows a re-entrant feature toward 1 e2/h which increases linearly in width with magnetic field. Rotating the magnetic field clearly attributes this experimental signature to SOI and by comparing our observations with a numerical model we extract a spin-orbit energy of approximately 6.5 meV, which is stronger than the spin-orbit energy obtained by other methods. Indium antimonide nanowires have large spin-orbit coupling, which can give rise to helical states that are an important part of proposals for topological quantum computing. Here the authors measure conductance through the helical states and extract a larger spin-orbit energy than obtained before.
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Sun Z, Seidman DN, Lauhon LJ. Nanowire Kinking Modulates Doping Profiles by Reshaping the Liquid-Solid Growth Interface. NANO LETTERS 2017; 17:4518-4525. [PMID: 28658572 DOI: 10.1021/acs.nanolett.7b02071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Dopants modify the electronic properties of semiconductors, including their susceptibility to etching. In semiconductor nanowires doped during growth by the vapor-liquid-solid (VLS) process, it has been shown that nanofaceting of the liquid-solid growth interface influences strongly the radial distribution of dopants. Hence, the combination of facet-dependent doping and dopant selective etching provides a means to tune simultaneously the electronic properties and morphologies of nanowires. Using atom-probe tomography, we investigated the boron dopant distribution in Au catalyzed VLS grown silicon nanowires, which regularly kink between equivalent ⟨112⟩ directions. Segments alternate between radially uniform and nonuniform doping profiles, which we attribute to switching between a concave and convex faceted liquid-solid interface. Dopant selective etching was used to reveal and correlate the shape of the growth interface with the observed anisotropic doping.
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Affiliation(s)
- Zhiyuan Sun
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - David N Seidman
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
- Northwestern University Center for Atom-Probe Tomography (NUCAPT) , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Lincoln J Lauhon
- Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
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Assali S, Dijkstra A, Li A, Koelling S, Verheijen MA, Gagliano L, von den Driesch N, Buca D, Koenraad PM, Haverkort JEM, Bakkers EPAM. Growth and Optical Properties of Direct Band Gap Ge/Ge 0.87Sn 0.13 Core/Shell Nanowire Arrays. NANO LETTERS 2017; 17:1538-1544. [PMID: 28165747 DOI: 10.1021/acs.nanolett.6b04627] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Group IV semiconductor optoelectronic devices are now possible by using strain-free direct band gap GeSn alloys grown on a Ge/Si virtual substrate with Sn contents above 9%. Here, we demonstrate the growth of Ge/GeSn core/shell nanowire arrays with Sn incorporation up to 13% and without the formation of Sn clusters. The nanowire geometry promotes strain relaxation in the Ge0.87Sn0.13 shell and limits the formation of structural defects. This results in room-temperature photoluminescence centered at 0.465 eV and enhanced absorption above 98%. Therefore, direct band gap GeSn grown in a nanowire geometry holds promise as a low-cost and high-efficiency material for photodetectors operating in the short-wave infrared and thermal imaging devices.
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Affiliation(s)
- S Assali
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
| | - A Dijkstra
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
| | - A Li
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
- Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology , Pingleyuan 100, Beijing 100024, P. R. China
| | - S Koelling
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
| | - M A Verheijen
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
- Philips Innovation Laboratories Eindhoven , High Tech Campus 11, 5656AE Eindhoven, The Netherlands
| | - L Gagliano
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
| | - N von den Driesch
- Peter Gruenberg Institute 9 (PGI 9) and JARA-Fundamentals of Future Information Technologies , Forschungszentrum Juelich, 52428 Juelich, Germany
| | - D Buca
- Peter Gruenberg Institute 9 (PGI 9) and JARA-Fundamentals of Future Information Technologies , Forschungszentrum Juelich, 52428 Juelich, Germany
| | - P M Koenraad
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
| | - J E M Haverkort
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
| | - E P A M Bakkers
- Department of Applied Physics, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands
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