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Balasubramanian GPS, Lebedkina E, Goktas NI, Wagner JB, Hansen O, LaPierre R, Semenova E, Mølhave K, Beleggia M, Fiordaliso EM. In situoff-axis electron holography of real-time dopant diffusion in GaAs nanowires. NANOTECHNOLOGY 2022; 33:475705. [PMID: 35944428 DOI: 10.1088/1361-6528/ac880f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Off-axis electron holography was used to reveal remote doping in GaAs nanowires occurring duringin situannealing in a transmission electron microscope. Dynamic changes to the electrostatic potential caused by carbon dopant diffusion upon annealing were measured across GaAs nanowires with radial p-p+ core-shell junctions. Electrostatic potential profiles were extracted from holographic phase maps and built-in potentials (Vbi) and depletion layer widths (DLWs) were estimated as function of temperature over 300-873 K. Simulations in absence of remote doping predict a significant increase ofVbiand DLWs with temperature. In contrast, we measured experimentally a nearly constantVbiand a weak increase of DLWs. Moreover, we observed the appearance of a depression in the potential profile of the core upon annealing. We attribute these deviations from the predicted behavior to carbon diffusion from the shell to the core through the nanowire sidewalls, i.e. to remote doping, becoming significant at 673 K. The DLW in the p and p+ regions are in the 10-30 nm range.
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Affiliation(s)
| | - Elizaveta Lebedkina
- DTU Fotonik, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Nebile Isik Goktas
- Department of Engineering Physics, McMaster University, L8S 4L7 Hamilton, Ontario, Canada
| | | | - Ole Hansen
- DTU Nanolab, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Ray LaPierre
- Department of Engineering Physics, McMaster University, L8S 4L7 Hamilton, Ontario, Canada
| | - Elizaveta Semenova
- DTU Fotonik, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Kristian Mølhave
- DTU Nanolab, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Marco Beleggia
- DTU Nanolab, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
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2
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Echresh A, Arora H, Fuchs F, Li Z, Hübner R, Prucnal S, Schuster J, Zahn P, Helm M, Zhou S, Erbe A, Rebohle L, Georgiev YM. Electrical Characterization of Germanium Nanowires Using a Symmetric Hall Bar Configuration: Size and Shape Dependence. NANOMATERIALS 2021; 11:nano11112917. [PMID: 34835681 PMCID: PMC8620357 DOI: 10.3390/nano11112917] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 11/30/2022]
Abstract
The fabrication of individual nanowire-based devices and their comprehensive electrical characterization remains a major challenge. Here, we present a symmetric Hall bar configuration for highly p-type germanium nanowires (GeNWs), fabricated by a top-down approach using electron beam lithography and inductively coupled plasma reactive ion etching. The configuration allows two equivalent measurement sets to check the homogeneity of GeNWs in terms of resistivity and the Hall coefficient. The highest Hall mobility and carrier concentration of GeNWs at 5 K were in the order of 100 cm2/(Vs) and 4×1019cm−3, respectively. With a decreasing nanowire width, the resistivity increases and the carrier concentration decreases, which is attributed to carrier scattering in the region near the surface. By comparing the measured data with simulations, one can conclude the existence of a depletion region, which decreases the effective cross-section of GeNWs. Moreover, the resistivity of thin GeNWs is strongly influenced by the cross-sectional shape.
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Affiliation(s)
- Ahmad Echresh
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
- International Helmholtz Research School for Nanoelectronic Network, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany
- Institute of Applied Physics, Technical University of Dresden, 01062 Dresden, Germany
- Correspondence:
| | - Himani Arora
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
- International Helmholtz Research School for Nanoelectronic Network, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany
| | - Florian Fuchs
- Fraunhofer Institute for Electronic Nano Systems (ENAS), 09126 Chemnitz, Germany; (F.F.); (J.S.)
- Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126 Chemnitz, Germany
| | - Zichao Li
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
| | - René Hübner
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
| | - Slawomir Prucnal
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
| | - Jörg Schuster
- Fraunhofer Institute for Electronic Nano Systems (ENAS), 09126 Chemnitz, Germany; (F.F.); (J.S.)
- Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126 Chemnitz, Germany
| | - Peter Zahn
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
- International Helmholtz Research School for Nanoelectronic Network, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany
| | - Manfred Helm
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
- International Helmholtz Research School for Nanoelectronic Network, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany
- Institute of Applied Physics, Technical University of Dresden, 01062 Dresden, Germany
| | - Shengqiang Zhou
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
| | - Artur Erbe
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
- International Helmholtz Research School for Nanoelectronic Network, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany
| | - Lars Rebohle
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
| | - Yordan M. Georgiev
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany; (H.A.); (Z.L.); (R.H.); (S.P.); (P.Z.); (M.H.); (S.Z.); (A.E.); (L.R.); (Y.M.G.)
- International Helmholtz Research School for Nanoelectronic Network, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany
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Barrigón E, Heurlin M, Bi Z, Monemar B, Samuelson L. Synthesis and Applications of III-V Nanowires. Chem Rev 2019; 119:9170-9220. [PMID: 31385696 DOI: 10.1021/acs.chemrev.9b00075] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Low-dimensional semiconductor materials structures, where nanowires are needle-like one-dimensional examples, have developed into one of the most intensely studied fields of science and technology. The subarea described in this review is compound semiconductor nanowires, with the materials covered limited to III-V materials (like GaAs, InAs, GaP, InP,...) and III-nitride materials (GaN, InGaN, AlGaN,...). We review the way in which several innovative synthesis methods constitute the basis for the realization of highly controlled nanowires, and we combine this perspective with one of how the different families of nanowires can contribute to applications. One reason for the very intense research in this field is motivated by what they can offer to main-stream semiconductors, by which ultrahigh performing electronic (e.g., transistors) and photonic (e.g., photovoltaics, photodetectors or LEDs) technologies can be merged with silicon and CMOS. Other important aspects, also covered in the review, deals with synthesis methods that can lead to dramatic reduction of cost of fabrication and opportunities for up-scaling to mass production methods.
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Affiliation(s)
- Enrique Barrigón
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | - Magnus Heurlin
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden.,Sol Voltaics AB , Scheelevägen 63 , 223 63 Lund , Sweden
| | - Zhaoxia Bi
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | - Bo Monemar
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | - Lars Samuelson
- Division of Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
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4
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Dastjerdi MHT, Fiordaliso EM, Leshchenko ED, Akhtari-Zavareh A, Kasama T, Aagesen M, Dubrovskii VG, LaPierre RR. Three-fold Symmetric Doping Mechanism in GaAs Nanowires. NANO LETTERS 2017; 17:5875-5882. [PMID: 28903563 DOI: 10.1021/acs.nanolett.7b00794] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A new dopant incorporation mechanism in Ga-assisted GaAs nanowires grown by molecular beam epitaxy is reported. Off-axis electron holography revealed that p-type Be dopants introduced in situ during molecular beam epitaxy growth of the nanowires were distributed inhomogeneously in the nanowire cross-section, perpendicular to the growth direction. The active dopants showed a remarkable azimuthal distribution along the (111)B flat top of the nanowires, which is attributed to preferred incorporation along 3-fold symmetric truncated facets under the Ga droplet. A diffusion model is presented to explain the unique radial and azimuthal variation of the active dopants in the GaAs nanowires.
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Affiliation(s)
- M H T Dastjerdi
- Department of Engineering Physics, Centre for Emerging Device Technologies, McMaster University , Hamilton, Ontario Canada , L8S 4L7
| | - E M Fiordaliso
- Center for Electron Nanoscopy, Technical University of Denmark , DK-2800 Kongens Lyngby, Denmark
| | - E D Leshchenko
- ITMO University , Kronverkskiy pr. 49, 197101 St. Petersburg, Russia
| | - A Akhtari-Zavareh
- Department of Engineering Physics, Centre for Emerging Device Technologies, McMaster University , Hamilton, Ontario Canada , L8S 4L7
| | - T Kasama
- Center for Electron Nanoscopy, Technical University of Denmark , DK-2800 Kongens Lyngby, Denmark
| | - M Aagesen
- Gasp Solar ApS, Gregersensvej 7, DK-2630 Taastrup, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen, Denmark
| | - V G Dubrovskii
- ITMO University , Kronverkskiy pr. 49, 197101 St. Petersburg, Russia
- St. Petersburg Academic University , Khlopina 8/3, 194021 St. Petersburg, Russia
- Ioffe Physical Technical Institute of the Russian Academy of Sciences , Politekhnicheskaya 26, 194021 St. Petersburg, Russia
| | - R R LaPierre
- Department of Engineering Physics, Centre for Emerging Device Technologies, McMaster University , Hamilton, Ontario Canada , L8S 4L7
- ITMO University , Kronverkskiy pr. 49, 197101 St. Petersburg, Russia
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5
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Zhang Y, Fonseka HA, Aagesen M, Gott JA, Sanchez AM, Wu J, Kim D, Jurczak P, Huo S, Liu H. Growth of Pure Zinc-Blende GaAs(P) Core-Shell Nanowires with Highly Regular Morphology. NANO LETTERS 2017; 17:4946-4950. [PMID: 28758401 DOI: 10.1021/acs.nanolett.7b02063] [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
The growth of self-catalyzed core-shell nanowires (NWs) is investigated systematically using GaAs(P) NWs. The defects in the core NW are found to be detrimental for the shell growth. These defects are effectively eliminated by introducing beryllium (Be) doping during the NW core growth and hence forming Be-Ga alloy droplets that can effectively suppress the WZ nucleation and facilitate the droplet consumption. Shells with pure zinc-blende crystal quality and highly regular morphology are successfully grown on the defect-free NW cores and demonstrated an enhancement of one order of magnitude for room-temperature emission compared to that of the defective shells. These results provide useful information on guiding the growth of high-quality shell, which can greatly enhance the NW device performance.
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Affiliation(s)
- Yunyan Zhang
- Department of Electronic and Electrical Engineering, University College , London WC1E 7JE, United Kingdom
| | - H Aruni Fonseka
- Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Martin Aagesen
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen , Universitetsparken 5, 2100 Copenhagen, Denmark
| | - James A Gott
- Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Ana M Sanchez
- Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom
| | - Jiang Wu
- Department of Electronic and Electrical Engineering, University College , London WC1E 7JE, United Kingdom
| | - Dongyoung Kim
- Department of Electronic and Electrical Engineering, University College , London WC1E 7JE, United Kingdom
| | - Pamela Jurczak
- Department of Electronic and Electrical Engineering, University College , London WC1E 7JE, United Kingdom
| | - Suguo Huo
- London Centre for Nanotechnology, University College , London WC1H 0AH, United Kingdom
| | - Huiyun Liu
- Department of Electronic and Electrical Engineering, University College , London WC1E 7JE, United Kingdom
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6
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Kivisaari P, Berg A, Karimi M, Storm K, Limpert S, Oksanen J, Samuelson L, Pettersson H, Borgström MT. Optimization of Current Injection in AlGaInP Core-Shell Nanowire Light-Emitting Diodes. NANO LETTERS 2017; 17:3599-3606. [PMID: 28535346 DOI: 10.1021/acs.nanolett.7b00759] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Core-shell nanowires offer great potential to enhance the efficiency of light-emitting diodes (LEDs) and expand the attainable wavelength range of LEDs over the whole visible spectrum. Additionally, nanowire (NW) LEDs can offer both improved light extraction and emission enhancement if the diameter of the wires is not larger than half the emission wavelength (λ/2). However, AlGaInP nanowire LEDs have so far failed to match the high efficiencies of traditional planar technologies, and the parameters limiting the efficiency remain unidentified. In this work, we show by experimental and theoretical studies that the small nanowire dimensions required for efficient light extraction and emission enhancement facilitate significant loss currents, which result in a low efficiency in radial NW LEDs in particular. To this end, we fabricate AlGaInP core-shell nanowire LEDs where the nanowire diameter is roughly equal to λ/2, and we find that both a large loss current and a large contact resistance are present in the samples. To investigate the significant loss current observed in the experiments in more detail, we carry out device simulations accounting for the full 3D nanowire geometry. According to the simulations, the low efficiency of radial AlGaInP nanowire LEDs can be explained by a substantial hole leakage to the outer barrier layer due to the small layer thicknesses and the close proximity of the shell contact. Using further simulations, we propose modifications to the epitaxial structure to eliminate such leakage currents and to increase the efficiency to near unity without sacrificing the λ/2 upper limit of the nanowire diameter. To gain a better insight of the device physics, we introduce an optical output measurement technique to estimate an ideality factor that is only dependent on the quasi-Fermi level separation in the LED. The results show ideality factors in the range of 1-2 around the maximum LED efficiency even in the presence of a very large voltage loss, indicating that the technique is especially attractive for measuring nanowire LEDs at an early stage of development before electrical contacts have been optimized. The presented results and characterization techniques form a basis of how to simultaneously optimize the electrical and optical efficiency of core-shell nanowire LEDs, paving the way to nanowire light emitters that make true use of larger-than-unity Purcell factors and the consequently enhanced spontaneous emission.
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Affiliation(s)
- Pyry Kivisaari
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
| | - Alexander Berg
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
| | - Mohammad Karimi
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
- Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University , P.O. Box 823, SE-301 18 Halmstad, Sweden
| | - Kristian Storm
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
| | - Steven Limpert
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
| | - Jani Oksanen
- Engineered Nanosystems Group, Aalto University , P.O. Box 12200, FI-00076 Aalto, Finland
| | - Lars Samuelson
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
| | - Håkan Pettersson
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
- Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University , P.O. Box 823, SE-301 18 Halmstad, Sweden
| | - Magnus T Borgström
- Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden
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7
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Berg A, Heurlin M, Tsopanidis S, Pistol ME, Borgström MT. Growth of wurtzite Al x Ga 1-x P nanowire shells and characterization by Raman spectroscopy. NANOTECHNOLOGY 2017; 28:035706. [PMID: 27966463 DOI: 10.1088/1361-6528/28/3/035706] [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
The phonon energies of AlGaP in wurtzite crystal structure are generally not known, as opposed to their zincblende counterparts, because AlGaP crystallizes in zincblende phase in bulk and thin films structures. However, in nanowires AlGaP can be grown in wurtzite crystal structure. In this work we have grown wurtzite GaP/AlGaP/GaP core-shell nanowires by use of MOVPE. After developing suitable growth conditions, the Al composition was determined by STEM-EDX measurements and the wurtzite AlGaP phonon energies by Raman spectroscopy. Raman measurements show a peak shift with increasing Al composition in the AlGaP shell. We find that the phonon energies for wurtzite AlGaP are slightly lower than for zincblende AlGaP. Our results can be used to determine the Al composition in wurtzite AlGaP by Raman scattering.
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Affiliation(s)
- Alexander Berg
- Solid State Physics and NanoLund, Lund University, Box 118, SE-221 00, Lund, Sweden
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8
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Haas F, Zellekens P, Lepsa M, Rieger T, Grützmacher D, Lüth H, Schäpers T. Electron Interference in Hall Effect Measurements on GaAs/InAs Core/Shell Nanowires. NANO LETTERS 2017; 17:128-135. [PMID: 27991790 DOI: 10.1021/acs.nanolett.6b03611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present low-temperature magnetotransport measurements on GaAs/InAs core/shell nanowires contacted by regular source-drain leads as well as laterally attached Hall contacts, which only touch parts of the nanowire sidewalls. Low-temperature measurements between source and drain contacts show typical phase coherent effects, such as universal conductance fluctuations in a magnetic field aligned perpendicularly to the nanowire axis as well as Aharonov-Bohm-type oscillations in a parallel aligned magnetic field. However, the signal between the Hall contacts shows a Hall voltage buildup, when the magnetic field is turned perpendicular to the nanowire axis while current is driven through the wire using the source-drain contacts. At low temperatures, the phase coherent effects measured between source and drain leads are superimposed on the Hall voltage, which can be explained by nonlocal probing of large segments of the nanowire. In addition, the Aharonov-Bohm-type oscillations are also observed in the magnetoconductance at magnetic fields aligned parallel to the nanowire axis, using the laterally contacted leads. This measurement geometry hereby directly corresponds to classical Aharonov-Bohm experiments using planar quantum rings. In addition, the Hall voltage is used to characterize the nanowires in terms of charge carrier concentration and mobility, using temperature- and gate-dependent measurements as well as measurements in tilted magnetic fields. The GaAs/InAs core/shell nanowire used in combination with laterally attached contacts is therefore the ideal system to three-dimensionally combine quantum ring experiments using the cross-sectional plane and Hall experiments using the axial nanowire plane.
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Affiliation(s)
- Fabian Haas
- Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
- Jülich Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), 52425 Jülich, Germany
| | - Patrick Zellekens
- Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
- Jülich Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), 52425 Jülich, Germany
| | - Mihail Lepsa
- Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
- Jülich Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), 52425 Jülich, Germany
| | - Torsten Rieger
- Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
- Jülich Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), 52425 Jülich, Germany
| | - Detlev Grützmacher
- Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
- Jülich Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), 52425 Jülich, Germany
| | - Hans Lüth
- Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
- Jülich Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), 52425 Jülich, Germany
| | - Thomas Schäpers
- Peter Grünberg Institute 9, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
- Jülich Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), 52425 Jülich, Germany
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9
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Lindelöw F, Heurlin M, Otnes G, Dagytė V, Lindgren D, Hultin O, Storm K, Samuelson L, Borgström M. Doping evaluation of InP nanowires for tandem junction solar cells. NANOTECHNOLOGY 2016; 27:065706. [PMID: 26762762 DOI: 10.1088/0957-4484/27/6/065706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In order to push the development of nanowire-based solar cells further using optimized nanowire diameter and pitch, a doping evaluation of the nanowire geometry is necessary. We report on a doping evaluation of n-type InP nanowires with diameters optimized for light absorption, grown by the use of metal-organic vapor phase epitaxy in particle-assisted growth mode using tetraethyltin (TESn) as the dopant precursor. The charge carrier concentration was evaluated using four-probe resistivity measurements and spatially resolved Hall measurements. In order to reach the highest possible nanowire doping level, we set the TESn molar fraction at a high constant value throughout growth and varied the trimethylindium (TMIn) molar fraction for different runs. Analysis shows that the charge carrier concentration in nanowires grown with the highest TMIn molar fraction (not leading to kinking nanowires) results in a low carrier concentration of approximately 10(16) cm(-3). By decreasing the molar fraction of TMIn, effectively increasing the IV/III ratio, the carrier concentration increases up to a level of about 10(19) cm(-3), where it seems to saturate. Axial carrier concentration gradients along the nanowires are found, which can be correlated to a combination of changes in the nanowire growth rate, measured in situ by optical reflectometry, and polytypism of the nanowires observed in transmission electron microscopy.
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10
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Hultin O, Otnes G, Borgström MT, Björk M, Samuelson L, Storm K. Comparing Hall Effect and Field Effect Measurements on the Same Single Nanowire. NANO LETTERS 2016; 16:205-211. [PMID: 26599297 DOI: 10.1021/acs.nanolett.5b03496] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We compare and discuss the two most commonly used electrical characterization techniques for nanowires (NWs). In a novel single-NW device, we combine Hall effect and back-gated and top-gated field effect measurements and quantify the carrier concentrations in a series of sulfur-doped InP NWs. The carrier concentrations from Hall effect and field effect measurements are found to correlate well when using the analysis methods described in this work. This shows that NWs can be accurately characterized with available electrical methods, an important result toward better understanding of semiconductor NW doping.
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Affiliation(s)
- Olof Hultin
- Division of Solid State Physics, Lund University , P.O. Box 118, SE-22100 Lund, Sweden
| | - Gaute Otnes
- Division of Solid State Physics, Lund University , P.O. Box 118, SE-22100 Lund, Sweden
| | - Magnus T Borgström
- Division of Solid State Physics, Lund University , P.O. Box 118, SE-22100 Lund, Sweden
| | - Mikael Björk
- Sol Voltaics AB , Scheelevägen 22, SE-22363 Lund, Sweden
| | - Lars Samuelson
- Division of Solid State Physics, Lund University , P.O. Box 118, SE-22100 Lund, Sweden
| | - Kristian Storm
- Division of Solid State Physics, Lund University , P.O. Box 118, SE-22100 Lund, Sweden
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Berg A, Yazdi S, Nowzari A, Storm K, Jain V, Vainorius N, Samuelson L, Wagner JB, Borgström MT. Radial Nanowire Light-Emitting Diodes in the (AlxGa1-x)yIn1-yP Material System. NANO LETTERS 2016; 16:656-662. [PMID: 26708274 DOI: 10.1021/acs.nanolett.5b04401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nanowires have the potential to play an important role for next-generation light-emitting diodes. In this work, we present a growth scheme for radial nanowire quantum-well structures in the AlGaInP material system using a GaInP nanowire core as a template for radial growth with GaInP as the active layer for emission and AlGaInP as charge carrier barriers. The different layers were analyzed by X-ray diffraction to ensure lattice-matched radial structures. Furthermore, we evaluated the material composition and heterojunction interface sharpness by scanning transmission electron microscopy energy dispersive X-ray spectroscopy. The electro-optical properties were investigated by injection luminescence measurements. The presented results can be a valuable track toward radial nanowire light-emitting diodes in the AlGaInP material system in the red/orange/yellow color spectrum.
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Affiliation(s)
- Alexander Berg
- Solid State Physics and NanoLund, Lund University , Box 118, SE-221 00, Lund, Sweden
| | - Sadegh Yazdi
- Center for Electron Nanoscopy, Technical University of Denmark , DK 2800 Kgs. Lyngby, Denmark
| | - Ali Nowzari
- Solid State Physics and NanoLund, Lund University , Box 118, SE-221 00, Lund, Sweden
| | - Kristian Storm
- Solid State Physics and NanoLund, Lund University , Box 118, SE-221 00, Lund, Sweden
| | - Vishal Jain
- Solid State Physics and NanoLund, Lund University , Box 118, SE-221 00, Lund, Sweden
- Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University , Box 823, SE-301 18 Halmstad, Sweden
| | - Neimantas Vainorius
- Solid State Physics and NanoLund, Lund University , Box 118, SE-221 00, Lund, Sweden
| | - Lars Samuelson
- Solid State Physics and NanoLund, Lund University , Box 118, SE-221 00, Lund, Sweden
| | - Jakob B Wagner
- Center for Electron Nanoscopy, Technical University of Denmark , DK 2800 Kgs. Lyngby, Denmark
| | - Magnus T Borgström
- Solid State Physics and NanoLund, Lund University , Box 118, SE-221 00, Lund, Sweden
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Yazdi S, Berg A, Borgström MT, Kasama T, Beleggia M, Samuelson L, Wagner JB. Doping GaP Core-Shell Nanowire pn-Junctions: A Study by Off-Axis Electron Holography. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:2687-2695. [PMID: 25656570 DOI: 10.1002/smll.201403361] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/24/2014] [Indexed: 06/04/2023]
Abstract
The doping process in GaP core-shell nanowire pn-junctions using different precursors is evaluated by mapping the nanowires' electrostatic potential distribution by means of off-axis electron holography. Three precursors, triethyltin (TESn), ditertiarybutylselenide, and silane are investigated for n-type doping of nanowire shells; among them, TESn is shown to be the most efficient precursor. Off-axis electron holography reveals higher electrostatic potentials in the regions of nanowire cores grown by the vapor-liquid-solid (VLS) mechanism (axial growth) than the regions grown parasitically by the vapor-solid (VS) mechanism (radial growth), attributed to different incorporation efficiency between VLS and VS of unintentional p-type carbon doping originating from the trimethylgallium precursor. This study shows that off-axis electron holography of doped nanowires is unique in terms of the ability to map the electrostatic potential and thereby the active dopant distribution with high spatial resolution.
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Affiliation(s)
- Sadegh Yazdi
- Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark
| | - Alexander Berg
- Solid State Physics, Lund University, Box 118, S-221 00, Lund, Sweden
| | | | - Takeshi Kasama
- Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark
| | - Marco Beleggia
- Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark
| | - Lars Samuelson
- Solid State Physics, Lund University, Box 118, S-221 00, Lund, Sweden
| | - Jakob B Wagner
- Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark
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Nowzari A, Heurlin M, Jain V, Storm K, Hosseinnia A, Anttu N, Borgström MT, Pettersson H, Samuelson L. A comparative study of absorption in vertically and laterally oriented InP core-shell nanowire photovoltaic devices. NANO LETTERS 2015; 15:1809-14. [PMID: 25671437 DOI: 10.1021/nl504559g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We have compared the absorption in InP core-shell nanowire p-i-n junctions in lateral and vertical orientation. Arrays of vertical core-shell nanowires with 400 nm pitch and 280 nm diameter, as well as corresponding lateral single core-shell nanowires, were configured as photovoltaic devices. The photovoltaic characteristics of the samples, measured under 1 sun illumination, showed a higher absorption in lateral single nanowires compared to that in individual vertical nanowires, arranged in arrays with 400 nm pitch. Electromagnetic modeling of the structures confirmed the experimental observations and showed that the absorption in a vertical nanowire in an array depends strongly on the array pitch. The modeling demonstrated that, depending on the array pitch, absorption in a vertical nanowire can be lower or higher than that in a lateral nanowire with equal absorption predicted at a pitch of 510 nm for our nanowire geometry. The technology described in this Letter facilitates quantitative comparison of absorption in laterally and vertically oriented core-shell nanowire p-i-n junctions and can aid in the design, optimization, and performance evaluation of nanowire-based core-shell photovoltaic devices.
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Affiliation(s)
- Ali Nowzari
- Division of Solid State Physics and The Nanometer Structure Consortium (nmC@LU), Lund University , Box 118, 22100 Lund, Sweden
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Lindgren D, Hultin O, Heurlin M, Storm K, Borgström MT, Samuelson L, Gustafsson A. Study of carrier concentration in single InP nanowires by luminescence and Hall measurements. NANOTECHNOLOGY 2015; 26:045705. [PMID: 25559040 DOI: 10.1088/0957-4484/26/4/045705] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The free electron carrier concentrations in single InP core-shell nanowires are determined by micro-photoluminescence, cathodoluminescence (CL) and Hall effect measurements. The results from luminescence measurements were obtained by solving the Fermi-Dirac integral, as well as by analyzing the peak full width at half maximum (FWHM). Furthermore, the platform used for Hall effect measurements, combined with spot mode CL spectroscopy, is used to determine the carrier concentrations at specific positions along single nanowires. The results obtained via luminescence measurements provide an accurate and rapid feedback technique for the epitaxial development of doping incorporation in nanowires. The technique has been employed on several series of samples in which growth parameters, such as V/III-ratio, temperature and dopant flows, were investigated in an optimization procedure. The correlation between the Hall effect and luminescence measurements for extracting the carrier concentration of different samples were in excellent agreement.
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Affiliation(s)
- David Lindgren
- Lund University, Solid State Physics and the Nanometer structure consortium, Box 118, S-221 00, Lund, Sweden
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Gao Q, Saxena D, Wang F, Fu L, Mokkapati S, Guo Y, Li L, Wong-Leung J, Caroff P, Tan HH, Jagadish C. Selective-area epitaxy of pure wurtzite InP nanowires: high quantum efficiency and room-temperature lasing. NANO LETTERS 2014; 14:5206-11. [PMID: 25115241 DOI: 10.1021/nl5021409] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We report the growth of stacking-fault-free and taper-free wurtzite InP nanowires with diameters ranging from 80 to 600 nm using selective-area metal-organic vapor-phase epitaxy and experimentally determine a quantum efficiency of ∼50%, which is on par with InP epilayers. We also demonstrate room-temperature, photonic mode lasing from these nanowires. Their excellent structural and optical quality opens up new possibilities for both fundamental quantum optics and optoelectronic devices.
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Affiliation(s)
- Qian Gao
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, ‡Australian National Fabrication Facility, Research School of Physics and Engineering, and §Centre for Advanced Microscopy, The Australian National University , Canberra, ACT 0200, Australia
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