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Mosberg AB, van Helvoort ATJ, Ramasse Q. Bending Needles and Breaking Wires: Useful Failures in Nanowire Probing. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:424-425. [PMID: 37613197 DOI: 10.1093/micmic/ozad067.200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
| | | | - Quentin Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, United Kingdom
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2
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Leis A, Cherepanov V, Voigtländer B, Tautz FS. Nanoscale tip positioning with a multi-tip scanning tunneling microscope using topography images. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:013702. [PMID: 35104957 DOI: 10.1063/5.0073059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Multi-tip scanning tunneling microscopy (STM) is a powerful method to perform charge transport measurements at the nanoscale. With four STM tips positioned on the surface of a sample, four-point resistance measurements can be performed in dedicated geometric configurations. Here, we present an alternative to the most often used scanning electron microscope imaging to infer the corresponding tip positions. After the initial coarse positioning is monitored by an optical microscope, STM scanning itself is used to determine the inter-tip distances. A large STM overview scan serves as a reference map. Recognition of the same topographic features in the reference map and in small scale images with the individual tips allows us to identify the tip positions with an accuracy of about 20 nm for a typical tip spacing of ∼1μm. In order to correct for effects such as the non-linearity of the deflection, creep, and hysteresis of the piezoelectric elements of the STM, a careful calibration has to be performed.
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Affiliation(s)
- Arthur Leis
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Vasily Cherepanov
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Bert Voigtländer
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - F Stefan Tautz
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
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3
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Shen B, Huang L, Shen J, Meng L, Kluender EJ, Wolverton C, Tian B, Mirkin CA. Synthesis of Metal-Capped Semiconductor Nanowires from Heterodimer Nanoparticle Catalysts. J Am Chem Soc 2020; 142:18324-18329. [PMID: 33078944 DOI: 10.1021/jacs.0c09222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Semiconductor nanowires (NWs) capped with metal nanoparticles (NPs) show multifunctional and synergistic properties, which are important for applications in the fields of catalysis, photonics, and electronics. Conventional colloidal syntheses of this class of hybrid structures require complex sequential seeded growth, where each section requires its own set of growth conditions, and methods for preparing such wires are not universal. Here, we report a new and general method for synthesizing metal-semiconductor nanohybrids based on particle catalysts, prepared by scanning probe block copolymer lithography, and chemical vapor deposition. In this process, metallic heterodimer NPs were used as catalysts for NW growth to form semiconductor NWs capped with metallic particles (Au, Ag, Co, Ni). Interestingly, the growth processes for NWs on NPs are regioselective and controlled by the chemical composition of the metallic heterodimer used. Using a systematic experimental approach, paired with density functional theory calculations, we were able to postulate three different growth modes, one without precedent.
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4
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Lord AM, Consonni V, Cossuet T, Donatini F, Wilks SP. Schottky Contacts on Polarity-Controlled Vertical ZnO Nanorods. ACS APPLIED MATERIALS & INTERFACES 2020; 12:13217-13228. [PMID: 32091196 DOI: 10.1021/acsami.9b23260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Polarity-controlled growth of ZnO by chemical bath deposition provides a method for controlling the crystal orientation of vertical nanorod arrays. The ability to define the morphology and structure of the nanorods is essential to maximizing the performance of optical and electrical devices such as piezoelectric nanogenerators; however, well-defined Schottky contacts to the polar facets of the structures have yet to be explored. In this work, we demonstrate a process to fabricate metal-semiconductor-metal device structures from vertical arrays with Au contacts on the uppermost polar facets of the nanorods and show that the O-polar nanorods (∼0.44 eV) have a greater effective barrier height than the Zn-polar nanorods (∼0.37 eV). Oxygen plasma treatment is shown by cathodoluminescence spectroscopy to affect midgap defects associated with radiative emissions, which improves the Schottky contacts from weakly rectifying to strongly rectifying. Interestingly, the plasma treatment is shown to have a much greater effect in reducing the number of carriers in O-polar nanorods through quenching of the donor-type substitutional hydrogen on oxygen sites (HO) when compared to the zinc-vacancy-related hydrogen defect complexes (VZn-nH) in Zn-polar nanorods that evolve to lower-coordinated complexes. The effect on HO in the O-polar nanorods coincides with a large reduction in the visible-range defects, producing a lower conductivity and creating the larger effective barrier heights. This combination can allow radiative losses and charge leakage to be controlled, enhancing devices such as dynamic photodetectors, strain sensors, and light-emitting diodes while showing that the O-polar nanorods can outperform Zn-polar nanorods in such applications.
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Affiliation(s)
- Alex M Lord
- Centre for NanoHealth, College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
| | - Vincent Consonni
- Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, F-38000 Grenoble, France
| | - Thomas Cossuet
- Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, F-38000 Grenoble, France
| | - Fabrice Donatini
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, F-38000 Grenoble, France
| | - Steve P Wilks
- Multidisciplinary Nanotechnology Centre, Department of Physics, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
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5
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Effects of Applied Voltages on the Charge Transport Properties in a ZnO Nanowire Field Effect Transistor. MATERIALS 2020; 13:ma13020268. [PMID: 31936145 PMCID: PMC7014215 DOI: 10.3390/ma13020268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/23/2019] [Accepted: 12/31/2019] [Indexed: 01/30/2023]
Abstract
We investigate the effect of applied gate and drain voltages on the charge transport properties in a zinc oxide (ZnO) nanowire field effect transistor (FET) through temperature- and voltage-dependent measurements. Since the FET based on nanowires is one of the fundamental building blocks in potential nanoelectronic applications, it is important to understand the transport properties relevant to the variation in electrically applied parameters for devices based on nanowires with a large surface-to-volume ratio. In this work, the threshold voltage shift due to a drain-induced barrier-lowering (DIBL) effect was observed using a Y-function method. From temperature-dependent current-voltage (I-V) analyses of the fabricated ZnO nanowire FET, it is found that space charge-limited conduction (SCLC) mechanism is dominant at low temperatures and low voltages; in particular, variable-range hopping dominates the conduction in the temperature regime from 4 to 100 K, whereas in the high-temperature regime (150–300 K), the thermal activation transport is dominant, diminishing the SCLC effect. These results are discussed and explained in terms of the exponential distribution and applied voltage-induced variation in the charge trap states at the band edge.
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Mukherjee A, Yun H, Shin DH, Nam J, Munshi AM, Dheeraj DL, Fimland BO, Weman H, Kim KS, Lee SW, Kim DC. Single GaAs Nanowire/Graphene Hybrid Devices Fabricated by a Position-Controlled Microtransfer and an Imprinting Technique for an Embedded Structure. ACS APPLIED MATERIALS & INTERFACES 2019; 11:13514-13522. [PMID: 30892012 DOI: 10.1021/acsami.8b20581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We developed a new technique to fabricate single nanowire devices with reliable graphene/nanowire contacts using a position-controlled microtransfer and an embedded nanowire structure in a planar junction configuration. A thorough study of electrical properties and fabrication challenges of single p-GaAs nanowire/graphene devices was carried out in two different device configurations: (1) a graphene bottom-contact device where the nanowire-graphene contact junction is formed by transferring a nanowire on top of graphene and (2) a graphene top-contact device where the nanowire-graphene contact junction is formed by transferring graphene on top of an embedded nanowire. For the graphene top-contact devices, graphene-nanowire-metal devices, where graphene is used as one electrode and metal is the other electrode to a nanowire, and graphene-nanowire-graphene devices, where both electrodes to a nanowire are graphene, were investigated and compared with conventional metal/p-GaAs nanowire devices. Conventional metal/p-GaAs nanowire contact devices were further investigated in embedded and nonembedded nanowire device configurations. A significantly improved current in the embedded device configuration is explained with a "parallel resistors model" where the high-resistance parts with the metal-semiconductor Schottky contact and the low-resistance parts with noncontacted facets of the hexagonal nanowires are taken into consideration. Consistently, the nonembedded nanowire structure is found to be depleted much easier than the embedded nanowires from which an estimation for a fully depleted condition has also been established.
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Affiliation(s)
- Anjan Mukherjee
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Hoyeol Yun
- School of Physics , Konkuk University , 05029 Seoul , Republic of Korea
| | - Dong Hoon Shin
- Department of Physics , Ewha Womans University , 03760 Seoul , Republic of Korea
| | - Jungtae Nam
- Department of Physics and Graphene Research Institute , Sejong University , 05006 Seoul , Republic of Korea
| | - A Mazid Munshi
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Dasa L Dheeraj
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Bjørn-Ove Fimland
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Helge Weman
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
| | - Keun Soo Kim
- Department of Physics and Graphene Research Institute , Sejong University , 05006 Seoul , Republic of Korea
| | - Sang Wook Lee
- Department of Physics , Ewha Womans University , 03760 Seoul , Republic of Korea
| | - Dong-Chul Kim
- Department of Electronic Systems , Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim , Norway
- CrayoNano AS , Sluppenvegen 6 , NO-7037 Trondheim , Norway
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Xing S, Lin L, Huo J, Zou G, Sheng X, Liu L, Zhou YN. Plasmon-Induced Heterointerface Thinning for Schottky Barrier Modification of Core/Shell SiC/SiO 2 Nanowires. ACS APPLIED MATERIALS & INTERFACES 2019; 11:9326-9332. [PMID: 30757894 DOI: 10.1021/acsami.8b20860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this work, plasmon-induced heterointerface thinning for Schottky barrier modification of core/shell SiC/SiO2 nanowires is conducted by femtosecond (fs) laser irradiation. The incident energy of polarized fs laser (50 fs, 800 nm) is confined in the SiO2 shell of the nanowire due to strong plasmonic localization in the region of the electrode-nanowire junction. With intense nonlinear absorption in SiO2, the thickness of the SiO2 layer can be thinned in a controllable way. The tuning of the SiO2 barrier layer allows the promotion of electron transportation at the electrode-nanowire interface. The switching voltage of the rectifying junction made by the SiC/SiO2 nanowire can be significantly tuned from 15.7 to 1 V. When selectively thinning at source and drain electrodes and leaving the SiO2 barrier layer at the gate electrode intact, a metal/oxide/semiconductor (MOS) device is fabricated with low leakage current. This optically controlled interfacial engineering technology should be applicable for MOS components and other heterogeneous integration structures.
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8
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Voigtländer B, Cherepanov V, Korte S, Leis A, Cuma D, Just S, Lüpke F. Invited Review Article: Multi-tip scanning tunneling microscopy: Experimental techniques and data analysis. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:101101. [PMID: 30399776 DOI: 10.1063/1.5042346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/25/2018] [Indexed: 06/08/2023]
Abstract
In scanning tunneling microscopy, we witness in recent years a paradigm shift from "just imaging" to detailed spectroscopic measurements at the nanoscale and multi-tip scanning tunneling microscope (STM) is a technique following this trend. It is capable of performing nanoscale charge transport measurements like a "multimeter at the nanoscale." Distance-dependent four-point measurements, the acquisition of nanoscale potential maps at current carrying nanostructures and surfaces, as well as the acquisition of I - V curves of nanoelectronic devices are examples of the capabilities of the multi-tip STM technique. In this review, we focus on two aspects: How to perform the multi-tip STM measurements and how to analyze the acquired data in order to gain insight into nanoscale charge transport processes for a variety of samples. We further discuss specifics of the electronics for multi-tip STM and the properties of tips for multi-tip STM, and present methods for a tip approach to nanostructures on insulating substrates. We introduce methods on how to extract the conductivity/resistivity for mixed 2D/3D systems from four-point measurements, how to measure the conductivity of 2D sheets, and how to introduce scanning tunneling potentiometry measurements with a multi-tip setup. For the example of multi-tip measurements at freestanding vapor liquid solid grown nanowires, we discuss contact resistances as well as the influence of the presence of the probing tips on the four point measurements.
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Affiliation(s)
- Bert Voigtländer
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich and JARA-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Vasily Cherepanov
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich and JARA-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Stefan Korte
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich and JARA-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Arthur Leis
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich and JARA-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - David Cuma
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich and JARA-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Sven Just
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich and JARA-Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - Felix Lüpke
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich and JARA-Fundamentals of Future Information Technology, 52425 Jülich, Germany
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9
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Jasulaneca L, Kosmaca J, Meija R, Andzane J, Erts D. Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches - materials solutions and operational conditions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:271-300. [PMID: 29441272 PMCID: PMC5789396 DOI: 10.3762/bjnano.9.29] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 12/25/2017] [Indexed: 05/08/2023]
Abstract
This review summarizes relevant research in the field of electrostatically actuated nanobeam-based nanoelectromechanical (NEM) switches. The main switch architectures and structural elements are briefly described and compared. Investigation methods that allow for exploring coupled electromechanical interactions as well as studies of mechanically or electrically induced effects are covered. An examination of the complex nanocontact behaviour during various stages of the switching cycle is provided. The choice of the switching element and the electrode is addressed from the materials perspective, detailing the benefits and drawbacks for each. An overview of experimentally demonstrated NEM switching devices is provided, and together with their operational parameters, the reliability issues and impact of the operating environment are discussed. Finally, the most common NEM switch failure modes and the physical mechanisms behind them are reviewed and solutions proposed.
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Affiliation(s)
| | | | | | | | - Donats Erts
- Institute of Chemical Physics
- Department of Chemistry, University of Latvia, Raina Blvd. 19, Riga, LV-1586, Latvia
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10
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Lord AM, Ramasse QM, Kepaptsoglou DM, Periwal P, Ross FM, Wilks SP. Stability of Schottky and Ohmic Au Nanocatalysts to ZnO Nanowires. NANO LETTERS 2017; 17:6626-6636. [PMID: 29024594 DOI: 10.1021/acs.nanolett.7b02561] [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
Manufacturable nanodevices must now be the predominant goal of nanotechnological research to ensure the enhanced properties of nanomaterials can be fully exploited and fulfill the promise that fundamental science has exposed. Here, we test the electrical stability of Au nanocatalyst-ZnO nanowire contacts to determine the limits of the electrical transport properties and the metal-semiconductor interfaces. While the transport properties of as-grown Au nanocatalyst contacts to ZnO nanowires have been well-defined, the stability of the interfaces over lengthy time periods and the electrical limits of the ohmic or Schottky function have not been studied. In this work, we use a recently developed iterative analytical process that directly correlates multiprobe transport measurements with subsequent aberration-corrected scanning transmission electron microscopy to study the electrical, structural, and chemical properties when the nanowires are pushed to their electrical limits and show structural changes occur at the metal-nanowire interface or at the nanowire midshaft. The ohmic contacts exhibit enhanced quantum-mechanical edge-tunneling transport behavior because of additional native semiconductor material at the contact edge due to a strong metal-support interaction. The low-resistance nature of the ohmic contacts leads to catastrophic breakdown at the middle of the nanowire span where the maximum heating effect occurs. Schottky-type Au-nanowire contacts are observed when the nanowires are in the as-grown pristine state and display entirely different breakdown characteristics. The higher-resistance rectifying I-V behavior degrades as the current is increased which leads to a permanent weakening of the rectifying effect and atomic-scale structural changes at the edge of the Au interface where the tunneling current is concentrated. Furthermore, to study modified nanowires such as might be used in devices the nanoscale tunneling path at the interface edge of the ohmic nanowire contacts is removed with a simple etch treatment and the nanowires show similar I-V characteristics during breakdown as the Schottky pristine contacts. Breakdown is shown to occur either at the nanowire midshaft or at the Au contact depending on the initial conductivity of the Au contact interface. These results demonstrate the Au-nanowire structures are capable of withstanding long periods of electrical stress and are stable at high current densities ensuring they are ideal components for nanowire-device designs while providing the flexibility of choosing the electrical transport properties which other Au-nanowire systems cannot presently deliver.
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Affiliation(s)
- Alex M Lord
- Centre for NanoHealth, College of Engineering, University of Swansea , Singleton Park SA2 8PP, United Kingdom
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Keckwick Lane, Daresbury WA4 4AD, United Kingdom
| | - Despoina M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Keckwick Lane, Daresbury WA4 4AD, United Kingdom
| | - Priyanka Periwal
- Department of Electrical Engineering, University of Cambridge , Cambridge CB0 3FA, United Kingdom
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, United States of America
| | - Frances M Ross
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, United States of America
| | - Steve P Wilks
- Multidisciplinary Nanotechnology Centre, Department of Physics, College of Science, University of Swansea , Singleton Park, SA2 8PP, United Kingdom
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11
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Lord AM, Evans JE, Barnett CJ, Allen MW, Barron AR, Wilks SP. Surface sensitivity of four-probe STM resistivity measurements of bulk ZnO correlated to XPS. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:384001. [PMID: 28678024 DOI: 10.1088/1361-648x/aa7dc8] [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
Multi-probe instruments based on scanning tunnelling microscopy (STM) are becoming increasingly common for their ability to perform nano- to atomic-scale investigations of nanostructures, surfaces and in situ reactions. A common configuration is the four-probe STM often coupled with in situ scanning electron microscopy (SEM) that allows precise positioning of the probes onto surfaces and nanostructures enabling electrical and scanning experiments to be performed on highly localised regions of the sample. In this paper, we assess the sensitivity of four-probe STM for in-line resistivity measurements of the bulk ZnO surface. The measurements allow comparisons to established models that are used to relate light plasma treatments (O and H) of the surfaces to the resistivity measurements. The results are correlated to x-ray photoelectron spectroscopy (XPS) and show that four-probe STM can detect changes in surface and bulk conduction mechanisms that are beyond conventional monochromatic XPS.
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Affiliation(s)
- Alex M Lord
- Centre for NanoHealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP, United Kingdom
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12
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Lord AM, Ramasse QM, Kepaptsoglou DM, Evans JE, Davies PR, Ward MB, Wilks SP. Modifying the Interface Edge to Control the Electrical Transport Properties of Nanocontacts to Nanowires. NANO LETTERS 2017; 17:687-694. [PMID: 28001420 DOI: 10.1021/acs.nanolett.6b03699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Selecting the electrical properties of nanomaterials is essential if their potential as manufacturable devices is to be reached. Here, we show that the addition or removal of native semiconductor material at the edge of a nanocontact can be used to determine the electrical transport properties of metal-nanowire interfaces. While the transport properties of as-grown Au nanocatalyst contacts to semiconductor nanowires are well-studied, there are few techniques that have been explored to modify the electrical behavior. In this work, we use an iterative analytical process that directly correlates multiprobe transport measurements with subsequent aberration-corrected scanning transmission electron microscopy to study the effects of chemical processes that create structural changes at the contact interface edge. A strong metal-support interaction that encapsulates the Au nanocontacts over time, adding ZnO material to the edge region, gives rise to ohmic transport behavior due to the enhanced quantum-mechanical tunneling path. Removal of the extraneous material at the Au-nanowire interface eliminates the edge-tunneling path, producing a range of transport behavior that is dependent on the final interface quality. These results demonstrate chemically driven processes that can be factored into nanowire-device design to select the final properties.
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Affiliation(s)
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SFTC Daresbury Campus , Keckwick Lane, Daresbury WA4 4AD, United Kingdom
| | - Despoina M Kepaptsoglou
- SuperSTEM Laboratory, SFTC Daresbury Campus , Keckwick Lane, Daresbury WA4 4AD, United Kingdom
| | | | - Philip R Davies
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University , Park Place, Cardiff CF10 3AT, United Kingdom
| | - Michael B Ward
- Institute for Materials Research, University of Leeds , Leeds, LS2 9JT United Kingdom
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13
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Naldoni A, Montini T, Malara F, Mróz MM, Beltram A, Virgili T, Boldrini CL, Marelli M, Romero-Ocaña I, Delgado JJ, Dal Santo V, Fornasiero P. Hot Electron Collection on Brookite Nanorods Lateral Facets for Plasmon-Enhanced Water Oxidation. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03092] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Alberto Naldoni
- CNR − Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133 Milano, Italy
| | - Tiziano Montini
- Dipartimento
di Scienze Chimiche e Farmaceutiche e Unita di Ricerca ICCOM-CNR Trieste,
INSTM Trieste, Università degli Studi di Trieste, Via L. Giorgieri
1, 34127 Trieste, Italy
| | - Francesco Malara
- CNR − Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133 Milano, Italy
| | - Marta M. Mróz
- CNR
- Istituto di Fotonica e Nanotecnologie (IFN), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy
| | - Alessandro Beltram
- Dipartimento
di Scienze Chimiche e Farmaceutiche e Unita di Ricerca ICCOM-CNR Trieste,
INSTM Trieste, Università degli Studi di Trieste, Via L. Giorgieri
1, 34127 Trieste, Italy
| | - Tersilla Virgili
- CNR
- Istituto di Fotonica e Nanotecnologie (IFN), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy
| | - Chiara L. Boldrini
- CNR − Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133 Milano, Italy
| | - Marcello Marelli
- CNR − Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133 Milano, Italy
| | - Ismael Romero-Ocaña
- Dipartimento
di Scienze Chimiche e Farmaceutiche e Unita di Ricerca ICCOM-CNR Trieste,
INSTM Trieste, Università degli Studi di Trieste, Via L. Giorgieri
1, 34127 Trieste, Italy
| | - Juan José Delgado
- Departamento
de Ciencia de los Materiales e Ingeniería Metalúrgica
y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, Campus Río San Pedro, 11510 Puerto Real, Cádiz, Spain
| | - Vladimiro Dal Santo
- CNR − Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133 Milano, Italy
| | - Paolo Fornasiero
- Dipartimento
di Scienze Chimiche e Farmaceutiche e Unita di Ricerca ICCOM-CNR Trieste,
INSTM Trieste, Università degli Studi di Trieste, Via L. Giorgieri
1, 34127 Trieste, Italy
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14
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Zhang L, Liu M, Zhao M, Dong Y, Zou C, Yang K, Yang Y, Huang S, Zhu DM. Electrical and optoelectrical modification of cadmium sulfide nanobelts by low-energy electron beam irradiation. NANOTECHNOLOGY 2016; 27:395704. [PMID: 27561004 DOI: 10.1088/0957-4484/27/39/395704] [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
In this report, we describe a method for modifying electrical and optoelectrical properties of CdS nanobelts using low-energy (lower than 10 keV) e-beam irradiation in a scanning electron microscope. The electrical conductivity of the nanobelts was dramatically improved via the irradiation of e-beams. The modified conductivity of the nanobelts depends on the energy of the e-beam; it exhibits a larger photocurrent and higher external quantum efficiency but slower time-response than that before the modification. A possible mechanism about the modification is the increase of electron accumulation (injected electrons) in the nanobelts due to e-beam irradiation. In addition, the optoelectrical modification could be caused by the trapped electrons in the nanobelts and the decrease of contact resistance between the nanobelts and metal electrodes induced by e-beam irradiation. The results of this work are significant for the in situ study of semiconductor nanostructures in the electron microscope. Besides, the method of electrical and optoelectrical modification presented here has potential application in electronics and optoelectronics.
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Affiliation(s)
- Lijie Zhang
- College of Chemistry and Materials Engineering, Wenzhou University 325027, People's Republic of China
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15
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Kryvchenkova O, Abdullah I, Macdonald JE, Elliott M, Anthopoulos T, Lin YH, Igić P, Kalna K, Cobley RJ. Nondestructive Method for Mapping Metal Contact Diffusion in In2O3 Thin-Film Transistors. ACS APPLIED MATERIALS & INTERFACES 2016; 8:25631-25636. [PMID: 27581104 PMCID: PMC5140079 DOI: 10.1021/acsami.6b10332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
The channel width-to-length ratio is an important transistor parameter for integrated circuit design. Contact diffusion into the channel during fabrication or operation alters the channel width and this important parameter. A novel methodology combining atomic force microscopy and scanning Kelvin probe microscopy (SKPM) with self-consistent modeling is developed for the nondestructive detection of contact diffusion on active devices. Scans of the surface potential are modeled using physically based Technology Computer Aided Design (TCAD) simulations when the transistor terminals are grounded and under biased conditions. The simulations also incorporate the tip geometry to investigate its effect on the measurements due to electrostatic tip-sample interactions. The method is particularly useful for semiconductor- and metal-semiconductor interfaces where the potential contrast resulting from dopant diffusion is below that usually detectable with scanning probe microscopy.
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Affiliation(s)
- Olga Kryvchenkova
- Electronic Systems Design Centre, Swansea University, Swansea SA1 8EN, U.K.
| | - Isam Abdullah
- School of Physics and Astronomy, Cardiff
University, The Parade, Cardiff CF24 3AA, U.K.
| | - John Emyr Macdonald
- School of Physics and Astronomy, Cardiff
University, The Parade, Cardiff CF24 3AA, U.K.
| | - Martin Elliott
- School of Physics and Astronomy, Cardiff
University, The Parade, Cardiff CF24 3AA, U.K.
| | - Thomas
D. Anthopoulos
- Department of Physics and Centre for Plastic Electronics,
Blackett Laboratory, Imperial College London, London SW7 2AZ, U.K.
| | - Yen-Hung Lin
- Department of Physics and Centre for Plastic Electronics,
Blackett Laboratory, Imperial College London, London SW7 2AZ, U.K.
| | - Petar Igić
- Electronic Systems Design Centre, Swansea University, Swansea SA1 8EN, U.K.
| | - Karol Kalna
- Electronic Systems Design Centre, Swansea University, Swansea SA1 8EN, U.K.
| | - Richard J. Cobley
- Electronic Systems Design Centre, Swansea University, Swansea SA1 8EN, U.K.
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16
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Barnett CJ, Kryvchenkova O, Smith NA, Kelleher L, Maffeis TGG, Cobley RJ. The effects of surface stripping ZnO nanorods with argon bombardment. NANOTECHNOLOGY 2015; 26:415701. [PMID: 26390967 DOI: 10.1088/0957-4484/26/41/415701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
ZnO nanorods are used in devices including field effects transistors, piezoelectric transducers, optoelectronics and gas sensors. However, for efficient and reproducible device operation and contact behaviour, surface contaminants must be removed or controlled. Here we use low doses of argon bombardment to remove surface contamination and make reproducible lower resistance contacts. Higher doses strip the surface of the nanorods allowing intrinsic surface measurements through a cross section of the material. Photoluminescence finds that the defect distribution is higher at the near-surface, falling away in to the bulk. Contacts to the n-type defect-rich surface are near-Ohmic, whereas stripping away the surface layers allows more rectifying Schottky contacts to be formed. The ability to select the contact type to ZnO nanorods offers a new way to customize device behaviour.
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Affiliation(s)
- Chris J Barnett
- Multidisciplinary Nanotechnology Centre, College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP, UK
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