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Weng Q, Deng W, Komiyama S, Sasaki T, Imada H, Lu W, Hosako I, Kim Y. Nanoscale thermal imaging of hot electrons by cryogenic terahertz scanning noise microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:063705. [PMID: 38888400 DOI: 10.1063/5.0206897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/03/2024] [Indexed: 06/20/2024]
Abstract
Nanoscale thermal imaging and temperature detection are of fundamental importance in diverse scientific and technological realms. Most nanoscale thermometry techniques focus on probing the temperature of lattice or phonons and are insensitive to nonequilibrium electrons, commonly referred to as "hot electrons." While terahertz scanning noise microscopy (SNoiM) has been demonstrated to be powerful in the thermal imaging of hot electrons, prior studies have been limited to room temperature. In this work, we report the development of a cryogenic SNoiM (Cryo-SNoiM) tailored for quantitative hot electron temperature detection at low temperatures. The microscope features a special two-chamber design where the sensitive terahertz detector, housed in a vacuum chamber, is efficiently cooled to ∼5 K using a pulse tube cryocooler. In a separate chamber, the atomic force microscope and the sample can be maintained at room temperature under ambient/vacuum conditions or cooled to ∼110 K via liquid nitrogen. This unique dual-chamber cooling system design enhances the efficacy of SNoiM measurements at low temperatures. It not only facilitates the pre-selection of tips at room temperature before cooling but also enables the quantitative derivation of local electron temperature without reliance on any adjustable parameters. The performance of Cryo-SNoiM is demonstrated through imaging the distribution of hot electrons in a cold, self-heated narrow metal wire. This instrumental innovation holds great promise for applications in imaging low-temperature hot electron dynamics and nonequilibrium transport phenomena across various material systems.
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Affiliation(s)
- Qianchun Weng
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Weijie Deng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, The Chinese Academy of Sciences, Shanghai 200083, China
| | - Susumu Komiyama
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
- Terahertz Technology Research Center, National Institute of Information and Communications Technology, Nukui-Kitamachi 4-2-1, Koganei, Tokyo 184-8795, Japan
| | - Toru Sasaki
- UNISOKU Co., Ltd., Hirakata, Osaka 573-0131, Japan
| | - Hiroshi Imada
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Wei Lu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, The Chinese Academy of Sciences, Shanghai 200083, China
| | - Iwao Hosako
- Terahertz Technology Research Center, National Institute of Information and Communications Technology, Nukui-Kitamachi 4-2-1, Koganei, Tokyo 184-8795, Japan
| | - Yousoo Kim
- Surface and Interface Science Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
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2
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Thermal Rectification and Thermal Logic Gates in Graded Alloy Semiconductors. ENERGIES 2022. [DOI: 10.3390/en15134685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Classical thermal rectification arises from the contact between two dissimilar bulk materials, each with a thermal conductivity (k) with a different temperature dependence. Here, we study thermal rectification in a Si(1−x)Gex alloy with a spatial dependence on the atomic composition. Rectification factors (R = kmax/kmin) of up to 3.41 were found. We also demonstrate the suitability of such an alloy for logic gates using a thermal AND gate as an example by controlling the thermal conductivity profile via the alloy composition. This system is readily extendable to other alloys, since it only depends on the effective thermal conductivity. These thermal devices are inherently advantageous alternatives to their electric counterparts, as they may be able to take advantage of otherwise undesired waste heat in the surroundings. Furthermore, the demonstration of logic operations is a step towards thermal computation.
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3
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Zhang Y, Zhu W, Borca-Tasciuc T. Thermal conductivity measurements of thin films by non-contact scanning thermal microscopy under ambient conditions. NANOSCALE ADVANCES 2021; 3:692-702. [PMID: 36133831 PMCID: PMC9417296 DOI: 10.1039/d0na00657b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 12/14/2020] [Indexed: 05/28/2023]
Abstract
Thermal conductivity measurements using Scanning Thermal Microscopy (SThM) usually involve heat transfer across the mechanical contact and liquid meniscus between the thermal probe and the sample. However, variations in contact conditions due to capillary effects at probe-sample contact and probe and sample wear due to mechanical contact interfere with accurate determination of the thermal conductivity. This paper presents measurements of thin film thermal conductivity using a SThM method employing a Wollaston probe in non-contact mode in synergy with detailed heat transfer analysis. In this technique, the thermal probe is scanned above the sample at a distance comparable with the mean free path of the ambient gas molecules. A Three-Dimensional Finite Element Model (3DFEM) that includes the specifics of the heat transfer between the sample and the probe in transition heat conduction regime was developed to predict the SThM probe thermal resistance and fit the thermal conductivity of the measured thin films. Proof-of-concept experimental in-plane thermal conductivity results for 240 nm and 46.6 nm Au films deposited on glass and silicon substrates were validated by experimental measurements of their electrical conductivity coupled with the Wiedemann-Franz law, with a discrepancy < 6.4%. Moreover, predictions based on a kinetic theory model for thin-film thermal conductivity agreed with the experimental results for the Au films with <6.6% discrepancy. To reduce the time and complexity of data analysis and facilitate experimental planning, an analytical model was also developed for the thermal transport between the Wollaston probe, ambient, and film-on-substrate samples. The accuracy of thin film thermal conductivity measurements using the analytical model was investigated using 3DFEM simulations. Fitted functions were developed for fast data analysis of thermal conductivity of thin films in the range of ∼100-600 W m-1 K-1 and thickness between ∼50-300 nm deposited on the two types of substrates investigated in this work, which yielded results with a discrepancy of 6-16.7% when compared to the Au films' thermal conductivity values.
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Affiliation(s)
- Yun Zhang
- Mechanical, Aerospace, and Nuclear Engineering Department, Rensselaer Polytechnic Institute Troy NY 12180 USA
| | - Wenkai Zhu
- Mechanical, Aerospace, and Nuclear Engineering Department, Rensselaer Polytechnic Institute Troy NY 12180 USA
| | - Theodorian Borca-Tasciuc
- Mechanical, Aerospace, and Nuclear Engineering Department, Rensselaer Polytechnic Institute Troy NY 12180 USA
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4
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Janus P, Szmigiel D, Sierakowski A, Rudek M, Gotszalk T. Active calibration reference of minimized height for characterization of scanning thermal microscopy systems. Ultramicroscopy 2020; 221:113188. [PMID: 33321422 DOI: 10.1016/j.ultramic.2020.113188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 11/17/2020] [Accepted: 11/30/2020] [Indexed: 11/28/2022]
Abstract
In this paper we describe the design, technology and application of a test and reference sample for calibration and characterization of scanning thermal microscopy (SThM) probes and systems. In our solution temperature field in thin film structure, which is being contacted with the thermal tip is controlled in the traceable manner. The developed technology, integrating plasma etching of Pt and chemical-mechanical planarization (CMP) processing, enabled manufacturing a nanosize 100 nm thick Pt resistor on SiO2 with topography profile below 10 nm. Four-point setup makes it possible to generate and measure (in other words control) a defined temperature field of such a structure. The size of the thermally active structure is big enough to enable reliable SThM measurements and small enough to reduce the parasitic heat transport between the surface and the cantilever platform. The proposed solution enables measurement of the output signal of the scanning thermal microscope measurement system when the temperature of the reference sample is varied in the quantitative way. Furthermore, basing on the determined sensitivity the assessment of the resolution capabilities is possible.
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Affiliation(s)
- Paweł Janus
- Sieć Badawcza Łukasiewicz - Instytut Mikroelektroniki i Fotoniki al. Lotników 32/46, Warszawa, Poland.
| | - Dariusz Szmigiel
- Sieć Badawcza Łukasiewicz - Instytut Mikroelektroniki i Fotoniki al. Lotników 32/46, Warszawa, Poland
| | - Andrzej Sierakowski
- Sieć Badawcza Łukasiewicz - Instytut Mikroelektroniki i Fotoniki al. Lotników 32/46, Warszawa, Poland
| | - Maciej Rudek
- Wroclaw University of Technology, ul. Janiszewskiego 32/46, Wrocław, 50-372, Poland
| | - Teodor Gotszalk
- Wroclaw University of Technology, ul. Janiszewskiego 32/46, Wrocław, 50-372, Poland
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5
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Fung ED, Venkataraman L. Too Cool for Blackbody Radiation: Overbias Photon Emission in Ambient STM Due to Multielectron Processes. NANO LETTERS 2020; 20:8912-8918. [PMID: 33206534 DOI: 10.1021/acs.nanolett.0c03994] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Light emission from tunnel junctions are a potential photon source for nanophotonic applications. Surprisingly, the photons emitted can have energies exceeding the energy supplied to the electrons by the bias. Three mechanisms for generating these so-called overbias photons have been proposed, but the relationship between these mechanisms has not been clarified. In this work, we argue that multielectron processes provide the best framework for understanding overbias light emission in tunnel junctions. Experimentally, we demonstrate for the first time that the superlinear dependence of emission on conductance predicted by this theory is robust to the temperature of the tunnel junction, indicating that tunnel junctions are a promising candidate for electrically driven broadband photon sources.
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Affiliation(s)
- E-Dean Fung
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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6
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Kim Y. Photoswitching Molecular Junctions: Platforms and Electrical Properties. Chemphyschem 2020; 21:2368-2383. [PMID: 32777151 DOI: 10.1002/cphc.202000564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/07/2020] [Indexed: 11/10/2022]
Abstract
Remarkable advances in technology have enabled the manipulation of individual molecules and the creation of molecular electronic devices utilizing single and ensemble molecules. Maturing the field of molecular electronics has led to the development of functional molecular devices, especially photoswitching or photochromic molecular junctions, which switch electronic properties under external light irradiation. This review introduces and summarizes the platforms for investigating the charge transport in single and ensemble photoswitching molecular junctions as well as the electronic properties of diverse photoswitching molecules such as diarylethene, azobenzene, dihydropyrene, and spiropyran. Furthermore, the article discusses the remaining challenges and the direction for moving forward in this area for future photoswitching molecular devices.
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Affiliation(s)
- Youngsang Kim
- Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA.,Current address, 7644 Ambrose way, California, 95831, USA
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7
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Sakai S, Hirata Y, Ito M, Shirakashi JI. Fabrication of atomic junctions with experimental parameters optimized using ground-state searches of Ising spin computing. Sci Rep 2019; 9:16211. [PMID: 31700094 PMCID: PMC6838177 DOI: 10.1038/s41598-019-52438-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 10/17/2019] [Indexed: 11/09/2022] Open
Abstract
Feedback-controlled electromigration (FCE) is employed to control metal nanowires with quantized conductance and create nanogaps and atomic junctions. In the FCE method, the experimental parameters are commonly selected based on experience. However, optimization of the parameters by way of tuning is intractable because of the impossibility of attempting all different combinations systematically. Therefore, we propose the use of the Ising spin model to optimize the FCE parameters, because this approach can search for a global optimum in a multidimensional solution space within a short calculation time. The FCE parameters were determined by using the energy convergence properties of the Ising spin model. We tested these parameters in actual FCE experiments, and we demonstrated that the Ising spin model could improve the controllability of the quantized conductance in atomic junctions. This result implies that the proposed method is an effective tool for the optimization of the FCE process in which an intelligent machine can conduct the research instead of humans.
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Affiliation(s)
- Shotaro Sakai
- Department of Electrical and Electronic Engineering, Tokyo University of Agriculture & Technology, Koganei, Tokyo, 184-8588, Japan
| | - Yosuke Hirata
- Department of Electrical and Electronic Engineering, Tokyo University of Agriculture & Technology, Koganei, Tokyo, 184-8588, Japan
| | - Mitsuki Ito
- Department of Electrical and Electronic Engineering, Tokyo University of Agriculture & Technology, Koganei, Tokyo, 184-8588, Japan
| | - Jun-Ichi Shirakashi
- Department of Electrical and Electronic Engineering, Tokyo University of Agriculture & Technology, Koganei, Tokyo, 184-8588, Japan.
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8
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Sattelkow J, Fröch JE, Winkler R, Hummel S, Schwalb C, Plank H. Three-Dimensional Nanothermistors for Thermal Probing. ACS APPLIED MATERIALS & INTERFACES 2019; 11:22655-22667. [PMID: 31154756 DOI: 10.1021/acsami.9b04497] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Accessing the thermal properties of materials or even full devices is a highly relevant topic in research and development. Along with the ongoing trend toward smaller feature sizes, the demands on appropriate instrumentation to access surface temperatures with high thermal and lateral resolution also increase. Scanning thermal microscopy is one of the most powerful technologies to fulfill this task down to the sub-100 nm regime, which, however, strongly depends on the nanoprobe design. In this study, we introduce a three-dimensional (3D) nanoprobe concept, which acts as a nanothermistor to access surface temperatures. Fabrication of nanobridges is done via 3D nanoprinting using focused electron beams, which allows direct-write fabrication on prestructured, self-sensing cantilever. As individual branch dimensions are in the sub-100 nm regime, mechanical stability is first studied by a combined approach of finite-element simulation and scanning electron microscopy-assisted in situ atomic force microscopy (AFM) measurements. After deriving the design rules for mechanically stable 3D nanobridges with vertical stiffness up to 50 N m-1, a material tuning approach is introduced to increase mechanical wear resistance at the tip apex for high-quality AFM imaging at high scan speeds. Finally, we demonstrate the electrical response in dependence of temperature and find a negative temperature coefficient of -(0.75 ± 0.2) 10-3 K-1 and sensing rates of 30 ± 1 ms K-1 at noise levels of ±0.5 K, which underlines the potential of our concept.
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Affiliation(s)
| | - Johannes E Fröch
- Graz Centre for Electron Microscopy , 8010 Graz , Austria
- Institute of Biomedical Materials and Devices , University of Technology Sydney , Ultimo , New South Wales 2007 , Australia
| | | | - Stefan Hummel
- Physics of Nanostructured Materials , University of Vienna , 1090 Vienna , Austria
| | | | - Harald Plank
- Graz Centre for Electron Microscopy , 8010 Graz , Austria
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9
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Quantifying Joule Heating and Mass Transport in Metal Nanowires During Controlled Electromigration. MATERIALS 2019; 12:ma12020310. [PMID: 30669491 PMCID: PMC6356241 DOI: 10.3390/ma12020310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 11/19/2022]
Abstract
The nanoscale heat dissipation (Joule heating) and mass transport during electromigration (EM) have attracted considerable attention in recent years. Here, the EM-driven movement of voids in gold (Au) nanowires of different shapes (width range: 50–300 nm) was directly observed by performing atomic force microscopy. Using the data, we determined the average mass transport rate to be 105 to 106 atoms/s. We investigated the heat dissipation in L-shaped, straight-shaped, and bowtie-shaped nanowires. The maximum Joule heating power of the straight-shaped nanowires was three times that of the bowtie-shaped nanowires, indicating that EM in the latter can be triggered by lower power. Based on the power dissipated by the nanowires, the local temperature during EM was estimated. Both the local temperature and junction voltage of the bowtie-shaped nanowires increased with the decrease in the Joule heating power and current, while the current density remained in the order of 108 A/cm2. The straight-shaped nanowires exhibited the same tendency. The local temperature at each feedback point could be simply estimated using the diffusive heat transport relationship. These results suggest that the EM-driven mass transport can be controlled at temperatures much lower than the melting point of Au.
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10
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Sawtelle SD, Kobos ZA, Reed MA. Critical temperature in feedback-controlled electromigration of gold nanostructures. NANOTECHNOLOGY 2019; 30:015201. [PMID: 30362467 DOI: 10.1088/1361-6528/aae673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This paper presents several experiments demonstrating the need for a more nuanced picture of electromigration (EM) than that of a fixed critical junction temperature at which EM onset occurs. Our data suggests that even for a fixed cross-sectional geometry the critical junction temperature for EM, T c , varies with environmental temperature, thermal resistance of adjacent regions, and even the direction of the current flow in asymmetric structures. We have performed feedback-controlled EM on nanowires at environmental temperatures between 75 and 260 K and fit the EM onset points with a constant junction power model. We find that average fit critical power is monotonically increasing with decreasing temperature, but is decidedly nonlinear at lower temperatures. We extract and compare the corresponding T c values using several different thermal models which utilize measured values of nanowire thermal conductivity for our devices: these models all agree on a moderately increasing T c with decreasing environmental temperature. This is tentatively explained by enhanced current-driven annealing on the voltage ramp prior to EM onset which decreases structural scattering, thereby increasing the critical temperature at which wind-force-driven hopping events will achieve a critical atomic flux. We also obtain fit critical power for a series of bowtie structures of identical constriction but varying adjacent thermal resistance (R th ), and estimate that T c in the constriction varies with R th for higher resistance structures. Critical power measurements on a second series of asymmetric bowties further suggests that T c also depends on the alignment of the electron flow with the temperature gradient at the constriction.
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Affiliation(s)
- S D Sawtelle
- Department of Applied Physics, Yale University, New Haven, CT 06520 United States of America
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11
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Harzheim A, Spiece J, Evangeli C, McCann E, Falko V, Sheng Y, Warner JH, Briggs GAD, Mol JA, Gehring P, Kolosov OV. Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions. NANO LETTERS 2018; 18:7719-7725. [PMID: 30418781 PMCID: PMC6328283 DOI: 10.1021/acs.nanolett.8b03406] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The influence of nanostructuring and quantum confinement on the thermoelectric properties of materials has been extensively studied. While this has made possible multiple breakthroughs in the achievable figure of merit, classical confinement, and its effect on the local Seebeck coefficient has mostly been neglected, as has the Peltier effect in general due to the complexity of measuring small temperature gradients locally. Here we report that reducing the width of a graphene channel to 100 nm changes the Seebeck coefficient by orders of magnitude. Using a scanning thermal microscope allows us to probe the local temperature of electrically contacted graphene two-terminal devices or to locally heat the sample. We show that constrictions in mono- and bilayer graphene facilitate a spatially correlated gradient in the Seebeck and Peltier coefficient, as evidenced by the pronounced thermovoltage Vth and heating/cooling response Δ TPeltier, respectively. This geometry dependent effect, which has not been reported previously in 2D materials, has important implications for measurements of patterned nanostructures in graphene and points to novel solutions for effective thermal management in electronic graphene devices or concepts for single material thermocouples.
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Affiliation(s)
- Achim Harzheim
- Department
of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom
| | - Jean Spiece
- Department
of Physics, Lancaster University, Bailrigg, LA1 4YB, Lancaster, United Kingdom
| | - Charalambos Evangeli
- Department
of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom
- Department
of Physics, Lancaster University, Bailrigg, LA1 4YB, Lancaster, United Kingdom
| | - Edward McCann
- Department
of Physics, Lancaster University, Bailrigg, LA1 4YB, Lancaster, United Kingdom
| | - Vladimir Falko
- School
of Physics and Astronomy, University of
Manchester, Oxford Road, M13 9PL, Manchester, United Kingdom
| | - Yuewen Sheng
- Department
of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom
| | - Jamie H. Warner
- Department
of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom
| | - G. Andrew D. Briggs
- Department
of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom
| | - Jan A. Mol
- Department
of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom
| | - Pascal Gehring
- Department
of Materials, University of Oxford, Parks Road, OX1 3PH, Oxford, United Kingdom
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg 1, 2628 CJ, Delft, Netherlands
- E-mail:
| | - Oleg V. Kolosov
- Department
of Physics, Lancaster University, Bailrigg, LA1 4YB, Lancaster, United Kingdom
- E-mail:
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12
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Rho J, Lim M, Lee SS, Lee BJ. AFM-thermoreflectance for simultaneous measurements of the topography and temperature. RSC Adv 2018; 8:27616-27622. [PMID: 35542752 PMCID: PMC9083913 DOI: 10.1039/c8ra05937c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 07/27/2018] [Indexed: 11/21/2022] Open
Abstract
To understand the thermal failure mechanisms of electronic devices, it is essential to measure the temperature and characterize the thermal properties of individual nanometer-scale transistors in electronic devices. Previously, scanning thermal microscopy (SThM) has been used to measure the local temperature with nanometer-scale spatial resolutions using a probe with a built-in temperature sensor. However, this type of temperature measurement requires additional equipment to process the temperature-sensing signals and expensive temperature-sensor-integrated probes fabricated by complicated MEMS processes. Here, we present a novel technique which enables the simultaneous measurement of the temperature and topography of nanostructures only with a conventional atomic force microscope (AFM) of the type commonly used for topography measurements and without any modifications of the probe and extra accessories for data acquisition. The underlying principle of the proposed technique is that the local temperature of a specimen is estimated quantitatively from the thermoreflectance of a bare silicon AFM probe that is in contact with a specimen. The temperature obtained by our technique is found to be consistent with a result obtained by SThM measurements. We propose a novel form of AFM-based thermometry capable of sub-100 nm spatial resolution only with a conventional AFM setup by exploiting the thermoreflectance characteristic of the AFM Si probe.![]()
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Affiliation(s)
- Jinsung Rho
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Daejeon 34141 South Korea
| | - Mikyung Lim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Daejeon 34141 South Korea
| | - Seung S Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Daejeon 34141 South Korea
| | - Bong Jae Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Daejeon 34141 South Korea
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13
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Zhuo GY, Su HC, Wang HY, Chan MC. In situ high-resolution thermal microscopy on integrated circuits. OPTICS EXPRESS 2017; 25:21548-21558. [PMID: 29041452 DOI: 10.1364/oe.25.021548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
The miniaturization of metal tracks in integrated circuits (ICs) can cause abnormal heat dissipation, resulting in electrostatic discharge, overvoltage breakdown, and other unwanted issues. Unfortunately, locating areas of abnormal heat dissipation is limited either by the spatial resolution or imaging acquisition speed of current thermal analytical techniques. A rapid, non-contact approach to the thermal imaging of ICs with sub-μm resolution could help to alleviate this issue. In this work, based on the intensity of the temperature-dependent two-photon fluorescence (TPF) of Rhodamine 6G (R6G) material, we developed a novel fast and non-invasive thermal microscopy with a sub-μm resolution. Its application to the location of hotspots that may evolve into thermally induced defects in ICs was also demonstrated. To the best of our knowledge, this is the first study to present high-resolution 2D thermal microscopic images of ICs, showing the generation, propagation, and distribution of heat during its operation. According to the demonstrated results, this scheme has considerable potential for future in situ hotspot analysis during the optimization stage of IC development.
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14
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Cui L, Miao R, Jiang C, Meyhofer E, Reddy P. Perspective: Thermal and thermoelectric transport in molecular junctions. J Chem Phys 2017. [DOI: 10.1063/1.4976982] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Longji Cui
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Ruijiao Miao
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chang Jiang
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Edgar Meyhofer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Pramod Reddy
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Materials Science and Engineering,
University of Michigan, Ann Arbor, Michigan 48109,
USA
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15
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Lagrange M, Sannicolo T, Muñoz-Rojas D, Lohan BG, Khan A, Anikin M, Jiménez C, Bruckert F, Bréchet Y, Bellet D. Understanding the mechanisms leading to failure in metallic nanowire-based transparent heaters, and solution for stability enhancement. NANOTECHNOLOGY 2017; 28:055709. [PMID: 28032620 DOI: 10.1088/1361-6528/28/5/055709] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Silver nanowire (AgNW) networks are emerging as one of the most promising alternatives to indium tin oxide (ITO) for transparent electrodes in flexible electronic devices. They can be used in a variety of optoelectronic applications such as solar cells, touch panels and organic light-emitting diodes. Recently they have also proven to be very efficient when used as transparent heaters (THs). In addition to the study of AgNW networks acting as THs in regular use, i.e. at low voltage and moderate temperature, their stability and physical behavior at higher voltages and for longer durations should be studied in view of their integration into real devices. The properties of AgNW networks deposited by spray coating on glass or flexible transparent substrates are thoroughly studied via in situ measurements. The AgNW networks' behavior at different voltages for different durations and under different atmospheric conditions, both in air and under vacuum, has been examined. At low voltage, a reversible electrical response is observed while irreversibility and even failure are observed at higher voltages. In order to gain a deeper insight into the behavior of AgNW networks used as THs, simple but realistic physical models are proposed and are found to be in fair agreement with the experimental data. Finally, as the stability of AgNW networks is a key issue, we demonstrate that coating AgNW networks with a very thin layer of TiO2 using atomic layer deposition (ALD) improves the material's resistance against electrical and thermal instabilities without altering optical transmittance. We show that the critical annealing temperature associated to network breakdown increases from 270 °C for the as-deposited AgNW networks to 420 °C for AgNW networks coated with TiO2. Similarly, the electrical failure which occurs at 7 V for the as-deposited networks increases to 13 V for TiO2-coated networks. TiO2 is also proved to stabilize AgNW networks during long duration operation and at high voltage. Temperature higher than 235 °C was achieved at 7 V without failure.
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Affiliation(s)
- M Lagrange
- Grenoble Alpes University, LMGP, CNRS, F-38000 Grenoble, France
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16
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Menges F, Riel H, Stemmer A, Gotsmann B. Nanoscale thermometry by scanning thermal microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:074902. [PMID: 27475585 DOI: 10.1063/1.4955449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/26/2016] [Indexed: 06/06/2023]
Abstract
Measuring temperature is a central challenge in nanoscience and technology. Addressing this challenge, we report the development of a high-vacuum scanning thermal microscope and a method for non-equilibrium scanning probe thermometry. The microscope is built inside an electromagnetically shielded, temperature-stabilized laboratory and features nanoscopic spatial resolution at sub-nanoWatt heat flux sensitivity. The method is a dual signal-sensing technique inferring temperature by probing a total steady-state heat flux simultaneously to a temporally modulated heat flux signal between a self-heated scanning probe sensor and a sample. Contact-related artifacts, which so far limit the reliability of nanoscopic temperature measurements by scanning thermal microscopy, are minimized. We characterize the microscope's performance and demonstrate the benefits of the new thermometry approach by studying hot spots near lithographically defined constrictions in a self-heated metal interconnect.
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Affiliation(s)
- Fabian Menges
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Heike Riel
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Andreas Stemmer
- Nanotechnology Group, ETH Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Bernd Gotsmann
- IBM Research - Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland
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17
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Menges F, Mensch P, Schmid H, Riel H, Stemmer A, Gotsmann B. Temperature mapping of operating nanoscale devices by scanning probe thermometry. Nat Commun 2016; 7:10874. [PMID: 26936427 PMCID: PMC4782057 DOI: 10.1038/ncomms10874] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/28/2016] [Indexed: 12/23/2022] Open
Abstract
Imaging temperature fields at the nanoscale is a central challenge in various areas of science and technology. Nanoscopic hotspots, such as those observed in integrated circuits or plasmonic nanostructures, can be used to modify the local properties of matter, govern physical processes, activate chemical reactions and trigger biological mechanisms in living organisms. The development of high-resolution thermometry techniques is essential for understanding local thermal non-equilibrium processes during the operation of numerous nanoscale devices. Here we present a technique to map temperature fields using a scanning thermal microscope. Our method permits the elimination of tip-sample contact-related artefacts, a major hurdle that so far has limited the use of scanning probe microscopy for nanoscale thermometry. We map local Peltier effects at the metal-semiconductor contacts to an indium arsenide nanowire and self-heating of a metal interconnect with 7 mK and sub-10 nm spatial temperature resolution.
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Affiliation(s)
- Fabian Menges
- IBM Research—Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
- Nanotechnology Group, ETH Zürich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Philipp Mensch
- IBM Research—Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Heinz Schmid
- IBM Research—Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Heike Riel
- IBM Research—Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Andreas Stemmer
- Nanotechnology Group, ETH Zürich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
| | - Bernd Gotsmann
- IBM Research—Zurich, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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18
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Kholid FN, Huang H, Zhang Y, Fan HJ. Multiple electrical breakdowns and electrical annealing using high current approximating breakdown current of silver nanowire network. NANOTECHNOLOGY 2016; 27:025703. [PMID: 26629590 DOI: 10.1088/0957-4484/27/2/025703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The failure of a silver nanowire (AgNW) random network due to high electric current density is described. The AgNW network breaks down as result of electromigration and Joule heating at junctions, which leads to destroyed interconnections between AgNWs. The AgNW network is not completely destroyed after breakdown, but instead is able to undergo multiple breakdowns after being cooled down, with increased resistance and reduced breakdown current density. The breakdown current density of AgNW network is J(max) = 25 A cm(-2) for a network with R(s) ~ 40 Ω sq(-1) outperforming a CuNW network. An effective electrical annealing method is demonstrated to decrease network resistance by 18% by periodically applying high current that is slightly lower than breakdown current with a period of 1 min for a few cycles.
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Affiliation(s)
- Farhan Nur Kholid
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore. Surface Technology Group, Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075, Singapore
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19
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Gazzadi GC, Frabboni S. Structural transitions in electron beam deposited Co-carbonyl suspended nanowires at high electrical current densities. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:1298-1305. [PMID: 26199833 PMCID: PMC4505147 DOI: 10.3762/bjnano.6.134] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/18/2015] [Indexed: 06/05/2023]
Abstract
Suspended nanowires (SNWs) have been deposited from Co-carbonyl precursor (Co2(CO)8) by focused electron beam induced deposition (FEBID). The SNWs dimensions are about 30-50 nm in diameter and 600-850 nm in length. The as-deposited material has a nanogranular structure of mixed face-centered cubic (FCC) and hexagonal close-packed (HCP) Co phases, and a composition of 80 atom % Co, 15 atom % O and 5 atom % C, as revealed by transmission electron microscopy (TEM) analysis and by energy-dispersive X-ray (EDX) spectroscopy, respectively. Current (I)-voltage (V) measurements with current densities up to 10(7) A/cm(2) determine different structural transitions in the SNWs, depending on the I-V history. A single measurement with a sudden current burst leads to a polycrystalline FCC Co structure extended over the whole wire. Repeated measurements at increasing currents produce wires with a split structure: one half is polycrystalline FCC Co and the other half is graphitized C. The breakdown current density is found at 2.1 × 10(7) A/cm(2). The role played by resistive heating and electromigration in these transitions is discussed.
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Affiliation(s)
- Gian Carlo Gazzadi
- S3 Center, Nanoscience Institute - CNR, Via Campi 213/a, 41125 Modena, Italy
| | - Stefano Frabboni
- S3 Center, Nanoscience Institute - CNR, Via Campi 213/a, 41125 Modena, Italy
- FIM Department, University of Modena and Reggio Emilia, Via Campi 213/a, 41125 Modena, Italy
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20
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Tayari V, McRae AC, Yiğen S, Island JO, Porter JM, Champagne AR. Tailoring 10 nm scale suspended graphene junctions and quantum dots. NANO LETTERS 2015; 15:114-119. [PMID: 25490053 DOI: 10.1021/nl503151g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The possibility to make 10 nm scale, and low-disorder, suspended graphene devices would open up many possibilities to study and make use of strongly coupled quantum electronics, quantum mechanics, and optics. We present a versatile method, based on the electromigration of gold-on-graphene bow-tie bridges, to fabricate low-disorder suspended graphene junctions and quantum dots with lengths ranging from 6 nm up to 55 nm. We control the length of the junctions, and shape of their gold contacts by adjusting the power at which the electromigration process is allowed to avalanche. Using carefully engineered gold contacts and a nonuniform downward electrostatic force, we can controllably tear the width of suspended graphene channels from over 100 nm down to 27 nm. We demonstrate that this lateral confinement creates high-quality suspended quantum dots. This fabrication method could be extended to other two-dimensional materials.
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Affiliation(s)
- Vahid Tayari
- Department of Physics, Concordia University , Montréal, Québec H4B 1R6, Canada
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21
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Kim Y, Jeong W, Kim K, Lee W, Reddy P. Electrostatic control of thermoelectricity in molecular junctions. NATURE NANOTECHNOLOGY 2014; 9:881-5. [PMID: 25282046 DOI: 10.1038/nnano.2014.209] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 08/21/2014] [Indexed: 05/03/2023]
Abstract
Molecular junctions hold significant promise for efficient and high-power-output thermoelectric energy conversion. Recent experiments have probed the thermoelectric properties of molecular junctions. However, electrostatic control of thermoelectric properties via a gate electrode has not been possible due to technical challenges in creating temperature differentials in three-terminal devices. Here, we show that extremely large temperature gradients (exceeding 1 × 10(9) K m(-1)) can be established in nanoscale gaps bridged by molecules, while simultaneously controlling their electronic structure via a gate electrode. Using this platform, we study prototypical Au-biphenyl-4,4'-dithiol-Au and Au-fullerene-Au junctions to demonstrate that the Seebeck coefficient and the electrical conductance of molecular junctions can be simultaneously increased by electrostatic control. Moreover, from our studies of fullerene junctions, we show that thermoelectric properties can be significantly enhanced when the dominant transport orbital is located close to the chemical potential (Fermi level) of the electrodes. These results illustrate the intimate relationship between the thermoelectric properties and charge transmission characteristics of molecular junctions and should enable systematic exploration of the recent computational predictions that promise extremely efficient thermoelectric energy conversion in molecular junctions.
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Affiliation(s)
- Youngsang Kim
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Wonho Jeong
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Kyeongtae Kim
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Woochul Lee
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Pramod Reddy
- 1] Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA [2] Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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