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Surdo S, Barillaro G. Voltage- and Metal-assisted Chemical Etching of Micro and Nano Structures in Silicon: A Comprehensive Review. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2400499. [PMID: 38644330 DOI: 10.1002/smll.202400499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/12/2024] [Indexed: 04/23/2024]
Abstract
Sculpting silicon at the micro and nano scales has been game-changing to mold bulk silicon properties and expand, in turn, applications of silicon beyond electronics, namely, in photonics, sensing, medicine, and mechanics, to cite a few. Voltage- and metal-assisted chemical etching (ECE and MaCE, respectively) of silicon in acidic electrolytes have emerged over other micro and nanostructuring technologies thanks to their unique etching features. ECE and MaCE have enabled the fabrication of novel structures and devices not achievable otherwise, complementing those feasible with the deep reactive ion etching (DRIE) technology, the gold standard in silicon machining. Here, a comprehensive review of ECE and MaCE for silicon micro and nano machining is provided. The chemistry and physics ruling the dissolution of silicon are dissected and similarities and differences between ECE and MaCE are discussed showing that they are the two sides of the same coin. The processes governing the anisotropic etching of designed silicon micro and nanostructures are analyzed, and the modulation of etching profile over depth is discussed. The preparation of micro- and nanostructures with tailored optical, mechanical, and thermo(electrical) properties is then addressed, and their applications in photonics, (bio)sensing, (nano)medicine, and micromechanical systems are surveyed. Eventually, ECE and MaCE are benchmarked against DRIE, and future perspectives are highlighted.
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Affiliation(s)
- Salvatore Surdo
- Dipartimento di Ingegneria dell'Informazione, Università di Pisa, via G. Caruso 16, Pisa, 56122, Italy
| | - Giuseppe Barillaro
- Dipartimento di Ingegneria dell'Informazione, Università di Pisa, via G. Caruso 16, Pisa, 56122, Italy
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2
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Li J, Weng L, Xie J, Amrit J, Ramiere A. Lévy walk of quasiballistic phonons in nanowires. Phys Rev E 2022; 105:064123. [PMID: 35854553 DOI: 10.1103/physreve.105.064123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Phonon transport in square-cross-section nanowires is studied using spectral Monte Carlo simulations. Our results show the evolution of the different transport regimes described by Lévy statistics as a function of the surface roughness-to-thermal wavelength ratio σ/λ. More precisely, the relationship between the Lévy index γ describing the mean free path distribution Ψ(Λ) and σ/λ is established for the classical diffusive regime, the superdiffusive regime, and the ballistic regime in the nanowire. Besides the conventional superdiffusive regime that is marked by Ψ(Λ) with a single heavy-tailed peak, we reveal an unconventional superdiffusive subregime featuring Ψ(Λ) with sawtooth oscillations when σ/λ∼0.01. Investigation of the direction of propagation of phonons shows a significant narrowing of the angular distribution around the long axis of the nanowire due to the diffuse scattering at rough boundaries when σ/λ>0.1. These results shed light on the transport mechanisms of quasiballistic phonons and will help in nanowire design for specific applications.
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Affiliation(s)
- Jincui Li
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Linxi Weng
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jie Xie
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Jay Amrit
- Laboratoire Interdisciplinaire des Sciences du Numérique, CNRS, Université Paris-Saclay, Rue du Belvédère, 91405 Orsay, France
| | - Aymeric Ramiere
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
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3
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Ci P, Sun M, Upadhyaya M, Song H, Jin L, Sun B, Jones MR, Ager JW, Aksamija Z, Wu J. Giant Isotope Effect of Thermal Conductivity in Silicon Nanowires. PHYSICAL REVIEW LETTERS 2022; 128:085901. [PMID: 35275649 DOI: 10.1103/physrevlett.128.085901] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 11/11/2021] [Accepted: 01/31/2022] [Indexed: 05/02/2023]
Abstract
Isotopically purified semiconductors potentially dissipate heat better than their natural, isotopically mixed counterparts as they have higher thermal conductivity (κ). But the benefit is low for Si at room temperature, amounting to only ∼10% higher κ for bulk ^{28}Si than for bulk natural Si (^{nat}Si). We show that in stark contrast to this bulk behavior, ^{28}Si (99.92% enriched) nanowires have up to 150% higher κ than ^{nat}Si nanowires with similar diameters and surface morphology. Using a first-principles phonon dispersion model, this giant isotope effect is attributed to a mutual enhancement of isotope scattering and surface scattering of phonons in ^{nat}Si nanowires, correlated via transmission of phonons to the native amorphous SiO_{2} shell. The Letter discovers the strongest isotope effect of κ at room temperature among all materials reported to date and inspires potential applications of isotopically enriched semiconductors in microelectronics.
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Affiliation(s)
- Penghong Ci
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Muhua Sun
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
| | - Meenakshi Upadhyaya
- Department of Electrical and Computer Engineering, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, USA
| | - Houfu Song
- Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen 518055, China
| | - Lei Jin
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Bo Sun
- Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen 518055, China
- Tsinghua Shenzhen International Graduate School and Guangdong Provincial Key Laboratory of Thermal Management Engineering and Materials, Shenzhen 518055, China
| | - Matthew R Jones
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
| | - Joel W Ager
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Zlatan Aksamija
- Department of Electrical and Computer Engineering, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, USA
| | - Junqiao Wu
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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4
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Maldovan M. Backscattering limit of nanoscale heat conduction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:395301. [PMID: 34323852 DOI: 10.1088/1361-648x/ac0852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
Being able to achieve extremely low thermal conductivities is of fundamental importance as well as of practical interest for thermal energy conversion and storage materials. By incorporating backscattering effects on thermal phonon transport, here we introduce a new lower limit for the thermal conductivities of nanoscale engineered materials. Our formulation shows that surface backscattering allows to reach a minimum limit for thermal energy transport at the nanoscale, achieving thermal conductivities which are orders of magnitude smaller than those obtained with classical approaches.
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Affiliation(s)
- Martin Maldovan
- School of Chemical & Biomolecular Engineering, School of Physics, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, United States of America
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5
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Mort R, Vorst K, Curtzwiler G, Jiang S. Biobased foams for thermal insulation: material selection, processing, modelling, and performance. RSC Adv 2021; 11:4375-4394. [PMID: 35424381 PMCID: PMC8694562 DOI: 10.1039/d0ra09287h] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 12/09/2020] [Indexed: 01/17/2023] Open
Abstract
With the urgent need for the development of sustainable materials and a circular economy, a surge of research regarding biobased materials and associated processing methods has resulted in many experimental biobased foams. Although several biobased foams are already shown to have thermal and mechanical properties competitive with expanded polystyrene, there remains a fundamental knowledge gap leading to limited understanding of the principles that determine performance. This review outlines the progress in this burgeoning field, introducing materials selection and processing, comparing performance, examining efforts in modelling physical properties, and discusses challenges in applying models to real biobased systems. The focus is on low thermal conductivity, which is a critical property for temperature-controlled applications such as packaging for refrigerated/frozen foods, medications, and vaccines as well as building materials. Currently, the trend in the field is moving towards fully biobased and compostable foams, though partially biobased polyurethane foams remain the most consistent performers. To illustrate the foam structure–property relationship, thermal conductivity, cell size, and density data were compiled. Given the complexity of biobased foams, heat transfer models aid in identifying crucial variables. However, data relevant to the insulation capability of biobased foams is not fully reported in many references. To address this issue, we employed a dimensional analysis to fill the gaps, revealing a power law correlation between thermal conductivity and relative density. Our approach is not intended as a robust prediction technique, but rather a simple demonstration of how biobased foams data could be utilized to predict the most promising materials and methods. This review outlines the progress in biobased foams with a focus on low thermal conductivity. It introduces materials selection and processing, compares performance, examines modelling of physical properties, and discusses challenges in applying models to real systems.![]()
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Affiliation(s)
- Rebecca Mort
- Materials Science and Engineering, Iowa State University Ames Iowa 50011 USA .,Polymer and Food Protection Consortium, Iowa State University Ames Iowa 50011 USA
| | - Keith Vorst
- Food Science and Human Nutrition, Iowa State University Ames Iowa 50011 USA.,Polymer and Food Protection Consortium, Iowa State University Ames Iowa 50011 USA
| | - Greg Curtzwiler
- Food Science and Human Nutrition, Iowa State University Ames Iowa 50011 USA.,Polymer and Food Protection Consortium, Iowa State University Ames Iowa 50011 USA
| | - Shan Jiang
- Materials Science and Engineering, Iowa State University Ames Iowa 50011 USA .,Polymer and Food Protection Consortium, Iowa State University Ames Iowa 50011 USA
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6
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Deng C, Wang X, Zhang R, Huang Y, Zhang X, Wang T. Stepped laser-ablation fabrication of concave micromirrors in rectangular optical waveguides for low loss vertical coupling. OPTICS EXPRESS 2020; 28:20264-20276. [PMID: 32680090 DOI: 10.1364/oe.395458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
In this report, we present a stepped laser-ablation method for the fabrication of concave micromirrors in rectangular optical waveguides. The numerically simulated vertical coupling loss of the reflection of the concave micromirror can be reduced to 1.53 dB. The processing parameters of the utilized excimer laser, such as the step number, width, and depth, were optimized to fabricate the concave micromirrors. After the thermal reflow process, the measured curve of the circular concave micromirrors obtained using a 3D optical profiler agreed well with a standard circle with a surface roughness of 39.56 nm. Furthermore, vertical coupling for 62.5 µm MMF revealed that the loss of the circular concave micromirror coated with a 50 nm thick Au film is as low as 1.83 dB, corresponding to a high coupling efficiency of 65.61%. This new, convenient, and efficient fabrication technology for the fabrication of concave micromirrors can be applied to vertical coupling for optical printed circuit board (OPCB) interconnection technology.
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7
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Malhotra A, Maldovan M. Phononic pathways towards rational design of nanowire heat conduction. NANOTECHNOLOGY 2019; 30:372002. [PMID: 31151114 DOI: 10.1088/1361-6528/ab261d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Thermal conduction in semiconductor nanowires is controlled by the transport of atomic vibrations also known as thermal phonons. The ability of nanowires to tailor the transport of thermal phonons stems from their precise atomic scale growth coupled with high structural surface to volume ratios. Understanding and manipulating thermal transport properties at the nanoscale is central for progress in the fields of microelectronics, optoelectronics, and thermoelectrics. Here, we review state-of-the-art advances in the understanding of nanowire thermal phonon transport and the design and fabrication of nanowires with tailored thermal conduction properties. We first introduce the basic physical mechanisms of thermal conduction at the nanoscale and detail recent developments in employing nanowires as thermal materials. We discuss and provide insight on different strategies to modulate nanowire thermal properties leveraging the underlying phonon transport processes occurring in nanowires. We also highlight challenges and key areas of interest to motivate future research and create exceptional capabilities to control heat flow in nanowires.
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Affiliation(s)
- Abhinav Malhotra
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States of America
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8
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Vaziri S, Yalon E, Muñoz Rojo M, Suryavanshi SV, Zhang H, McClellan CJ, Bailey CS, Smithe KKH, Gabourie AJ, Chen V, Deshmukh S, Bendersky L, Davydov AV, Pop E. Ultrahigh thermal isolation across heterogeneously layered two-dimensional materials. SCIENCE ADVANCES 2019; 5:eaax1325. [PMID: 31453337 PMCID: PMC6697438 DOI: 10.1126/sciadv.aax1325] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 07/10/2019] [Indexed: 05/28/2023]
Abstract
Heterogeneous integration of nanomaterials has enabled advanced electronics and photonics applications. However, similar progress has been challenging for thermal applications, in part due to shorter wavelengths of heat carriers (phonons) compared to electrons and photons. Here, we demonstrate unusually high thermal isolation across ultrathin heterostructures, achieved by layering atomically thin two-dimensional (2D) materials. We realize artificial stacks of monolayer graphene, MoS2, and WSe2 with thermal resistance greater than 100 times thicker SiO2 and effective thermal conductivity lower than air at room temperature. Using Raman thermometry, we simultaneously identify the thermal resistance between any 2D monolayers in the stack. Ultrahigh thermal isolation is achieved through the mismatch in mass density and phonon density of states between the 2D layers. These thermal metamaterials are an example in the emerging field of phononics and could find applications where ultrathin thermal insulation is desired, in thermal energy harvesting, or for routing heat in ultracompact geometries.
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Affiliation(s)
- Sam Vaziri
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Eilam Yalon
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Miguel Muñoz Rojo
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | | | - Huairuo Zhang
- Theiss Research Inc., La Jolla, CA 92037, USA
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, MA 20899, USA
| | - Connor J. McClellan
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Connor S. Bailey
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Kirby K. H. Smithe
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | | | - Victoria Chen
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Sanchit Deshmukh
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Leonid Bendersky
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, MA 20899, USA
| | - Albert V. Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, MA 20899, USA
| | - Eric Pop
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- Precourt Institute for Energy, Stanford University, Stanford, CA 94305, USA
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9
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Park W, Sohn J, Romano G, Kodama T, Sood A, Katz JS, Kim BSY, So H, Ahn EC, Asheghi M, Kolpak AM, Goodson KE. Impact of thermally dead volume on phonon conduction along silicon nanoladders. NANOSCALE 2018; 10:11117-11122. [PMID: 29873370 DOI: 10.1039/c8nr01788c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Thermal conduction in complex periodic nanostructures remains a key area of open questions and research, and a particularly provocative and challenging detail is the impact of nanoscale material volumes that do not lie along the optimal line of sight for conduction. Here, we experimentally study thermal transport in silicon nanoladders, which feature two orthogonal heat conduction paths: unobstructed line-of-sight channels in the axial direction and interconnecting bridges between them. The nanoladders feature an array of rectangular holes in a 10 μm long straight beam with a 970 nm wide and 75 nm thick cross-section. We vary the pitch of these holes from 200 nm to 1100 nm to modulate the contribution of bridges to the net transport of heat in the axial direction. The effective thermal conductivity, corresponding to reduced heat flux, decreases from ∼45 W m-1 K-1 to ∼31 W m-1 K-1 with decreasing pitch. By solving the Boltzmann transport equation using phonon mean free paths taken from ab initio calculations, we model thermal transport in the nanoladders, and experimental results show excellent agreement with the predictions to within ∼11%. A combination of experiments and calculations shows that with decreasing pitch, thermal transport in nanoladders approaches the counterpart in a straight beam equivalent to the line-of-sight channels, indicating that the bridges constitute a thermally dead volume. This study suggests that ballistic effects are dictated by the line-of-sight channels, providing key insights into thermal conduction in nanostructured metamaterials.
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Affiliation(s)
- Woosung Park
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.
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10
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Wang G, Wang C, Zhao J, Wang G, Park CB, Zhao G. Modelling of thermal transport through a nanocellular polymer foam: toward the generation of a new superinsulating material. NANOSCALE 2017; 9:5996-6009. [PMID: 28440837 DOI: 10.1039/c7nr00327g] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Superinsulating materials play a pivotal role in achieving the sustainable development of our modern world by improving energy efficiency, and reducing energy consumption and CO2 emission. Nanocellular polymer foams have been considered as a promising superinsulating material, but their development is yet to be achieved. The understanding of thermal transport through the nanocellular foam is crucial for developing this superinsulating material. Herein, we report an accurate mathematical model for the first time to quantitatively estimate thermal transport through the nanocellular polymer foam. This is realized by taking into account the phonon scattering effect, the Knudsen effect and the thin-film interference effect in modeling the thermal transport through solid conduction, gas conduction and thermal radiation, respectively. We demonstrate a quantitative relationship between the cellular structure and the equivalent thermal conductivity and present the optimum cellular structure scope for achieving the superinsulating performance. In particular, the significance of thermal radiation in the nanocellular polymer foam is emphasized. This mathematical model offers a very useful tool for deeply understanding thermal transport through the nanocellular polymer foams, and guiding the development of the new generation of superinsulating materials.
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Affiliation(s)
- Guilong Wang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, School of Materials Science and Engineering, Shandong University, Jinan, Shandong 250061, China. ,
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11
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Ray SK, Katiyar AK, Raychaudhuri AK. One-dimensional Si/Ge nanowires and their heterostructures for multifunctional applications-a review. NANOTECHNOLOGY 2017; 28:092001. [PMID: 28120815 DOI: 10.1088/1361-6528/aa565c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Remarkable progress has been made in the field of one-dimensional semiconductor nanostructures for electronic and photonic devices. Group-IV semiconductors and their heterostructures have dominated the years of success in microelectronic industry. However their use in photonic devices is limited since they exhibit poor optical activity due to indirect band gap nature of Si and Ge. Reducing their dimensions below a characteristic length scale of various fundamental parameters like exciton Bohr radius, phonon mean free path, critical size of magnetic domains, exciton diffusion length etc result in the significant modification of bulk properties. In particular, light emission from Si/Ge nanowires due to quantum confinement, strain induced band structure modification and impurity doping may lead to the integration of photonic components with mature silicon CMOS technology in near future. Several promising applications based on Si and Ge nanowires have already been well established and studied, while others are now at the early demonstration stage. The control over various forms of energy and carrier transport through the unconstrained dimension makes Si and Ge nanowires a promising platform to manufacture advanced solid-state devices. This review presents the progress of the research with emphasis on their potential application of Si/Ge nanowires and their heterostructures for electronic, photonic, sensing and energy devices.
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Affiliation(s)
- Samit K Ray
- Department of Physics, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
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12
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Chen TH, Lin PY, Chang HC, Chen CH. Enhanced thermoelectricity of three-dimensionally mesostructured Bi xSb 2-xTe 3 nanoassemblies: from micro-scaled open gaps to isolated sealed mesopores. NANOSCALE 2017; 9:3283-3292. [PMID: 28225112 DOI: 10.1039/c7nr00132k] [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
We describe an innovative interfacial design concept and nanostructuring of novel BixSb2-xTe3 (BST) nanoassembled films comprising unique air-solid interfaces from micro-scaled open gaps to isolated sealed mesopores, and high-quality solid-solid ones including the coherent grain boundaries and specific twins, utilizing pulsed laser deposition (PLD), for potentially activating multiple thermoelectric enhancing mechanisms. The unusual mesopore embedded BST films exhibit the highest power factor of ∼33 μW cm-1 K-2, which is comparable to or higher than the previously reported values for BST, and the corresponding relatively low thermal diffusivity in contrast to that for dense pore-less BST films evidently reveals the crucial role of the three-dimensionally and densely arranged air-solid interfaces in significantly arising the phonon scattering.
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Affiliation(s)
- Tsung-Han Chen
- Department of Materials Science and Engineering, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsin-Chu, 30010 Taiwan, Republic of China.
| | - Ping-Yu Lin
- Department of Materials Science and Engineering, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsin-Chu, 30010 Taiwan, Republic of China.
| | - Hsiu-Cheng Chang
- Department of Materials Science and Engineering, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsin-Chu, 30010 Taiwan, Republic of China.
| | - Chun-Hua Chen
- Department of Materials Science and Engineering, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsin-Chu, 30010 Taiwan, Republic of China.
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13
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Maire J, Anufriev R, Nomura M. Ballistic thermal transport in silicon nanowires. Sci Rep 2017; 7:41794. [PMID: 28150724 PMCID: PMC5288788 DOI: 10.1038/srep41794] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 12/28/2016] [Indexed: 11/16/2022] Open
Abstract
We have experimentally investigated the impact of dimensions and temperature on the thermal conductivity of silicon nanowires fabricated using a top-down approach. Both the width and temperature dependences of thermal conductivity agree with those in the existing literature. The length dependence of thermal conductivity exhibits a transition from semi-ballistic thermal phonon transport at 4 K to fully diffusive transport at room temperature. We additionally calculated the phonon dispersion in these structures in the framework of the theory of elasticity and showed that the thermal conductance increases with width. This agrees with our experimental observations and supports the pertinence of using the modified phonon dispersion at low temperatures.
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Affiliation(s)
- Jeremie Maire
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.,Laboratory for Integrated Micro Mechatronic Systems/National Center for Scientific Research-Institute of Industrial Science (LIMMS/CNRS-IIS), The University of Tokyo, Tokyo 153-8505, Japan
| | - Roman Anufriev
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan
| | - Masahiro Nomura
- Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.,Institute for Nano Quantum Information Electronics, The University of Tokyo, Tokyo 153-8505, Japan.,PRESTO, Japan Science and Technology Agency, Saitama 332-0012, Japan
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14
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Lee J, Lee W, Lim J, Yu Y, Kong Q, Urban JJ, Yang P. Thermal Transport in Silicon Nanowires at High Temperature up to 700 K. NANO LETTERS 2016; 16:4133-40. [PMID: 27243378 DOI: 10.1021/acs.nanolett.6b00956] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Thermal transport in silicon nanowires has captured the attention of scientists for understanding phonon transport at the nanoscale, and the thermoelectric figure-of-merit (ZT) reported in rough nanowires has inspired engineers to develop cost-effective waste heat recovery systems. Thermoelectric generators composed of silicon target high-temperature applications due to improved efficiency beyond 550 K. However, there have been no studies of thermal transport in silicon nanowires beyond room temperature. High-temperature measurements also enable studies of unanswered questions regarding the impact of surface boundaries and varying mode contributions as the highest vibrational modes are activated (Debye temperature of silicon is 645 K). Here, we develop a technique to investigate thermal transport in nanowires up to 700 K. Our thermal conductivity measurements on smooth silicon nanowires show the classical diameter dependence from 40 to 120 nm. In conjunction with Boltzmann transport equation, we also probe an increasing contribution of high-frequency phonons (optical phonons) in smooth silicon nanowires as the diameter decreases and the temperature increases. Thermal conductivity of rough silicon nanowires is significantly reduced throughout the temperature range, demonstrating a potential for efficient thermoelectric generation (e.g., ZT = 1 at 700 K).
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Affiliation(s)
- Jaeho Lee
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Department of Mechanical and Aerospace Engineering, University of California , Irvine, California 92697, United States
| | - Woochul Lee
- The Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Jongwoo Lim
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | | | | | - Jeffrey J Urban
- The Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Peidong Yang
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Kavli Energy Nanosciences Institute , Berkeley, California 94720, United States
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15
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Malhotra A, Maldovan M. Impact of Phonon Surface Scattering on Thermal Energy Distribution of Si and SiGe Nanowires. Sci Rep 2016; 6:25818. [PMID: 27174699 PMCID: PMC4865844 DOI: 10.1038/srep25818] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/22/2016] [Indexed: 11/09/2022] Open
Abstract
Thermal transport in nanostructures has attracted considerable attention in the last decade but the precise effects of surfaces on heat conduction have remained unclear due to a limited accuracy in the treatment of phonon surface scattering phenomena. Here, we investigate the impact of phonon-surface scattering on the distribution of thermal energy across phonon wavelengths and mean free paths in Si and SiGe nanowires. We present a rigorous and accurate description of phonon scattering at surfaces and predict and analyse nanowire heat spectra for different diameters and surface conditions. We show that the decrease in the diameter and increased roughness and correlation lengths makes the heat phonon spectra significantly shift towards short wavelengths and mean free paths. We also investigate the emergence of phonon confinement effects for small diameter nanowires and different surface scattering properties. Computed results for bulk materials show excellent agreement with recent experimentally-based approaches that reconstruct the mean-free-path heat spectra. Our phonon surface scattering model allows for an accurate theoretical extraction of heat spectra in nanowires and contributes to elucidate the development of critical phonon transport modes such as phonon confinement and coherent interference effects.
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Affiliation(s)
- Abhinav Malhotra
- School of Chemical &Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Martin Maldovan
- School of Chemical &Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.,School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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Mun H, Choi SM, Lee KH, Kim SW. Boundary Engineering for the Thermoelectric Performance of Bulk Alloys Based on Bismuth Telluride. CHEMSUSCHEM 2015; 8:2312-2326. [PMID: 25782971 DOI: 10.1002/cssc.201403485] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Indexed: 06/04/2023]
Abstract
Thermoelectrics, which transports heat for refrigeration or converts heat into electricity directly, is a key technology for renewable energy harvesting and solid-state refrigeration. Despite its importance, the widespread use of thermoelectric devices is constrained because of the low efficiency of thermoelectric bulk alloys. However, boundary engineering has been demonstrated as one of the most effective ways to enhance the thermoelectric performance of conventional thermoelectric materials such as Bi2 Te3 , PbTe, and SiGe alloys because their thermal and electronic transport properties can be manipulated separately by this approach. We review our recent progress on the enhancement of the thermoelectric figure of merit through boundary engineering together with the processing technologies for boundary engineering developed most recently using Bi2 Te3 -based bulk alloys. A brief discussion of the principles and current status of boundary-engineered bulk alloys for the enhancement of the thermoelectric figure of merit is presented. We focus mainly on (1) the reduction of the thermal conductivity by grain boundary engineering and (2) the reduction of thermal conductivity without deterioration of the electrical conductivity by phase boundary engineering. We also discuss the next potential approach using two boundary engineering strategies for a breakthrough in the area of bulk thermoelectric alloys.
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Affiliation(s)
- Hyeona Mun
- Department of Energy Science, Sungkyunkwan University, Suwon 440-476 (Korea)
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-476 (Korea)
| | - Soon-Mok Choi
- School of Energy, Materials and Chemical Engineering, Korea University of Technology and Education, Cheonan 330-708 (Korea)
| | - Kyu Hyoung Lee
- Department of Nano Applied Engineering, Kangwon National University, Chuncheon 200-701 (Korea).
| | - Sung Wng Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 440-476 (Korea).
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-476 (Korea).
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Li L, Jin C, Xu S, Yang J, Du H, Li G. Thermal conductivity of a single Bi₀.₅Sb₁.₅Te₃ single-crystalline nanowire. NANOTECHNOLOGY 2014; 25:415704. [PMID: 25249271 DOI: 10.1088/0957-4484/25/41/415704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Single-crystalline Bi₀.₅Sb₁.₅Te₃ nanowires were fabricated by a template-assisted pulsed electrodeposition technique; the thermal conductivity of a single Bi₀.₅Sb₁.₅Te₃ nanowire of different diameters was characterized through a self-heating 3 ω method. The temperature-dependent resistance measurements prove the semiconductor behavior of the nanowires. The extremely low thermal conductivity of the nanowires was found compared with the corresponding bulk, and the Umklapp peaks shift to a higher temperature as the decreasing nanowire's diameter decreases, which qualitatively agrees with the theoretical calculations based on the Callaway model. The boundary scattering plays an important role in the reduction of the thermal conductivity and in the shift of the Umklapp peak of the Bi₀.₅Sb₁.₅Te₃ nanowires.
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Affiliation(s)
- Liang Li
- Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
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Murphy KF, Piccione B, Zanjani MB, Lukes JR, Gianola DS. Strain- and defect-mediated thermal conductivity in silicon nanowires. NANO LETTERS 2014; 14:3785-3792. [PMID: 24885097 DOI: 10.1021/nl500840d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The unique thermal transport of insulating nanostructures is attributed to the convergence of material length scales with the mean free paths of quantized lattice vibrations known as phonons, enabling promising next-generation thermal transistors, thermal barriers, and thermoelectrics. Apart from size, strain and defects are also known to drastically affect heat transport when introduced in an otherwise undisturbed crystalline lattice. Here we report the first experimental measurements of the effect of both spatially uniform strain and point defects on thermal conductivity of an individual suspended nanowire using in situ Raman piezothermography. Our results show that whereas phononic transport in undoped Si nanowires with diameters in the range of 170-180 nm is largely unaffected by uniform elastic tensile strain, another means of disturbing a pristine lattice, namely, point defects introduced via ion bombardment, can reduce the thermal conductivity by over 70%. In addition to discerning surface- and core-governed pathways for controlling thermal transport in phonon-dominated insulators and semiconductors, we expect our novel approach to have broad applicability to a wide class of functional one- and two-dimensional nanomaterials.
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Affiliation(s)
- Kathryn F Murphy
- Department of Materials Science and Engineering and ‡Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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Dasgupta NP, Sun J, Liu C, Brittman S, Andrews SC, Lim J, Gao H, Yan R, Yang P. 25th anniversary article: semiconductor nanowires--synthesis, characterization, and applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:2137-84. [PMID: 24604701 DOI: 10.1002/adma.201305929] [Citation(s) in RCA: 357] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/12/2014] [Indexed: 05/18/2023]
Abstract
Semiconductor nanowires (NWs) have been studied extensively for over two decades for their novel electronic, photonic, thermal, electrochemical and mechanical properties. This comprehensive review article summarizes major advances in the synthesis, characterization, and application of these materials in the past decade. Developments in the understanding of the fundamental principles of "bottom-up" growth mechanisms are presented, with an emphasis on rational control of the morphology, stoichiometry, and crystal structure of the materials. This is followed by a discussion of the application of nanowires in i) electronic, ii) sensor, iii) photonic, iv) thermoelectric, v) photovoltaic, vi) photoelectrochemical, vii) battery, viii) mechanical, and ix) biological applications. Throughout the discussion, a detailed explanation of the unique properties associated with the one-dimensional nanowire geometry will be presented, and the benefits of these properties for the various applications will be highlighted. The review concludes with a brief perspective on future research directions, and remaining barriers which must be overcome for the successful commercial application of these technologies.
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Affiliation(s)
- Neil P Dasgupta
- Department of Chemistry, University of California Berkeley, Berkeley, CA, 94720, USA
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Liu D, Xie R, Yang N, Li B, Thong JTL. Profiling nanowire thermal resistance with a spatial resolution of nanometers. NANO LETTERS 2014; 14:806-812. [PMID: 24382310 DOI: 10.1021/nl4041516] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report a new technique to profile the thermal resistance along a nanowire with a spatial resolution of better than 20 nm. Using this technique, we mapped the thermal conductivity along a Si0.7Ge0.3/NiSi0.7Ge0.3 heterostructured nanowire. We also measured the interfacial thermal resistance (ITR) across the Si/NiSi2 interface embedded in Si/NiSi2 heterostructured nanowires. The ITR does not change even for adjacent interfaces as close as ∼ 50 atomic layers.
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Affiliation(s)
- Dan Liu
- Department of Physics and Centre for Computational Science and Engineering, National University of Singapore , Singapore 117546, Republic of Singapore
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Quiroga-González E, Carstensen J, Glynn C, O'Dwyer C, Föll H. Pore size modulation in electrochemically etched macroporous p-type silicon monitored by FFT impedance spectroscopy and Raman scattering. Phys Chem Chem Phys 2014; 16:255-63. [DOI: 10.1039/c3cp53600a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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