Walter de Heer

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Walter de Heer
Wdeheer.jpg
Citizenship Netherlands
Alma mater University of California, Berkeley
Known fordevelopment of graphene electronics
Scientific career
Fields condensed matter physics, metal clusters, carbon nanotubes, graphene
Institutions École Polytechnique Fédérale de Lausanne, Georgia Institute of Technology
Doctoral advisor Walter D. Knight

Walter Alexander "Walt" de Heer (born November 1949) is a Dutch physicist and nanoscience researcher known for discoveries in the electronic shell structure of metal clusters, magnetism in transition metal clusters, field emission and ballistic conduction in carbon nanotubes, and graphene-based electronics.

Contents

Academic career

De Heer earned a doctoral degree in physics from the University of California, Berkeley, in 1986 under the supervision of Walter D. Knight. He worked at the École Polytechnique Fédérale de Lausanne in Switzerland from 1987 to 1997, and is currently a Regents' Professor of Physics at the Georgia Institute of Technology. He directs the Epitaxial Graphene Laboratory in the School of Physics and leads the Epitaxial Graphene Interdisciplinary Research Group at the Georgia Tech Materials Research Science and Engineering Center.

Research

De Heer and his research groups have made significant contributions to several important areas in nanoscopic physics. As a graduate student at UC-Berkeley, he participated in groundbreaking research on alkali metal clusters that demonstrated the electronic shell structure of metal clusters. [1] This is a property of small metal clusters composed of few atoms that develop atom-like electronic properties (these clusters are also referred to as superatoms). In Switzerland, he developed methods of measuring the magnetic properties of cold metal clusters and described how magnetism develops in these clusters as their size increases from atomic to bulk. [2] He is the author of the most highly cited [3] review articles on metallic clusters. [4]

De Heer turned to carbon nanotubes in 1995, showing that they are excellent field emitters, with potential application to flat panel displays. [5] In 1998, he discovered that carbon nanotubes are ballistic conductors at room temperature, [6] [7] meaning that they conduct electrons over relatively large distances without resistance. This is a key selling point of nanotube- and graphene-based electronics.

His nanotube work led to consideration of the properties of "opened" carbon nanotubes and the development of graphene-based electronics, starting in 2001. [8] [9] Anticipating that patterned graphene structures would behave like interconnected carbon nanotubes, [8] he proposed several avenues of graphene preparation, including exfoliation of graphite flakes to oxidized silicon wafers and epitaxial growth on silicon carbide. [8] The latter was deemed most promising for large-scale integrated electronics, and was funded by Intel Corporation in 2003. [9] In 2004, the group was awarded additional funding from the National Science Foundation for the pursuit of graphene science. [10] [11] The first paper, "Two dimensional electron gas properties of ultrathin epitaxial graphite", was presented in March 2004 [12] at a meeting of the American Physical Society and published in December under the title, "Ultrathin epitaxial graphite: Two dimensional electron gas properties and a route towards graphene based electronics". [13] This paper, based primarily on data documented in 2003, [8] describes the first electrical measurements of epitaxial graphene, reports fabrication of the first graphene transistor, and outlines the desirable properties of graphene for use in graphene-based electronics. De Heer and coworkers Claire Berger and Phillip First hold the first patent on graphene-based electronics, [14] provisionally filed in June 2003. The approach championed by de Heer has the advantage of producing graphene directly on a high-quality electronic material (silicon carbide) and does not require isolation or transfer to any other substrate. [13] In 2014 de Heer and co-workers demonstrated exceptional ballistic transport properties of epigraphene nanoribbons on silicon carbide substrate steps. [15] This work was continued and in 2022 the  transport was demonstrated to  involve a zero-energy edge state with Majorana-fermion-like properties. [16]  This novel state is still not theoretically explained. In 2023 de Heer and coworkers demonstrated ultrahigh mobility semiconducting epigraphene. [17]

Honors and awards

He was elected a Fellow of the American Physical Society in 2003. [18]

In 2006, de Heer was named as one of the "Scientific American 50", a list of individuals/organizations honored for their contributions to science and society during the preceding year. [19] In 2007, he and his research group were awarded the prestigious W.M. Keck Foundation grant for continuation of work on "nanopatterned epitaxial graphene electronic devices that work at room temperature." [20] De Heer received IBM Faculty Awards in 2007 [21] and 2008, [22] and his work on graphene transistors was named as one of Technology Review's 10 emerging technologies "most likely to change the way we live" in 2008. [23] In September 2009, de Heer was awarded the ACSIN Nanoscience Prize "for his visionary work in developing the field of graphene nanoscience and technology". [24] De Heer has been awarded the 2010 Materials Research Society Medal "for his pioneering contributions to the science and technology of epitaxial graphene". [25] His h-index is currently 97. [26]

TICNN

The Tianjin International Center for Nanoparticles and Nanosystems (TICNN) is a research institute on the University of Tianjin (TJU) campus that was established in 2015 by de Heer’s ex-postdoc Lei Ma and Walt de Heer, designed by de Heer and constructed by Ma. TICNN has a comprehensive dedicated epigraphene laboratory designed to coordinate with, and complement the Georgia Tech epigraphene effort, with Georgia Tech’s endorsement. De Heer was the TICNN director until 2020. De Heer advised epigraphene research at the TICNN and remotely directed experiments that demonstrated ultrahigh mobility semiconducting epigraphene. [17] The deterioration of US-China relationships in general and the China Initiative specifically, ultimately led to the dissolution of the collaboration.

Letter to Nobel prize committee

In November 2010, De Heer wrote [27] to the Nobel prize committee criticising certain inaccuracies of the Scientific Background document relating to the award of the Nobel Prize to Andre Geim and Konstantin Novoselov which led to revisions in the Scientific Background document.

Related Research Articles

<span class="mw-page-title-main">Carbon nanotube</span> Allotropes of carbon with a cylindrical nanostructure

A carbon nanotube (CNT) is a tube made of carbon with a diameter in the nanometre range (nanoscale). They are one of the allotropes of carbon. Two broad classes of carbon nanotubes are recognized:

<span class="mw-page-title-main">Silicon carbide</span> Extremely hard semiconductor

Silicon carbide (SiC), also known as carborundum, is a hard chemical compound containing silicon and carbon. A wide bandgap semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite.

<span class="mw-page-title-main">Allotropes of carbon</span> Materials made only out of carbon

Carbon is capable of forming many allotropes due to its valency (tetravalent). Well-known forms of carbon include diamond and graphite. In recent decades, many more allotropes have been discovered and researched, including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger-scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperatures or extreme pressures. Around 500 hypothetical 3‑periodic allotropes of carbon are known at the present time, according to the Samara Carbon Allotrope Database (SACADA).

<span class="mw-page-title-main">Nanoelectromechanical systems</span> Class of devices for nanoscale functionality

Nanoelectromechanical systems (NEMS) are a class of devices integrating electrical and mechanical functionality on the nanoscale. NEMS form the next logical miniaturization step from so-called microelectromechanical systems, or MEMS devices. NEMS typically integrate transistor-like nanoelectronics with mechanical actuators, pumps, or motors, and may thereby form physical, biological, and chemical sensors. The name derives from typical device dimensions in the nanometer range, leading to low mass, high mechanical resonance frequencies, potentially large quantum mechanical effects such as zero point motion, and a high surface-to-volume ratio useful for surface-based sensing mechanisms. Applications include accelerometers and sensors to detect chemical substances in the air.

<span class="mw-page-title-main">Graphene</span> Hexagonal lattice made of carbon atoms

Graphene is an allotrope of carbon consisting of a single layer of atoms arranged in a honeycomb nanostructure. The name is derived from "graphite" and the suffix -ene, reflecting the fact that the graphite allotrope of carbon contains numerous double bonds in a two-dimensional sheet.

<span class="mw-page-title-main">Mildred Dresselhaus</span> American physicist and nanotechnologist (1930–2017)

Mildred Dresselhaus, known as the "Queen of Carbon Science", was an American physicist, materials scientist, and nanotechnologist. She was an institute professor and professor of both physics and electrical engineering at the Massachusetts Institute of Technology. She also served as the president of the American Physical Society, the chair of the American Association for the Advancement of Science, as well as the director of science in the US Department of Energy under the Bill Clinton Government. Dresselhaus won numerous awards including the Presidential Medal of Freedom, the National Medal of Science, the Enrico Fermi Award, the Kavli Prize and the Vannevar Bush Award.

<span class="mw-page-title-main">Marvin L. Cohen</span> American physicist

Marvin Lou Cohen is an American–Canadian theoretical physicist. He is a physics professor at the University of California, Berkeley. Cohen is a leading expert in the field of condensed matter physics. He is widely known for his seminal work on the electronic structure of solids.

Carbide-derived carbon (CDC), also known as tunable nanoporous carbon, is the common term for carbon materials derived from carbide precursors, such as binary (e.g. SiC, TiC), or ternary carbides, also known as MAX phases (e.g., Ti2AlC, Ti3SiC2). CDCs have also been derived from polymer-derived ceramics such as Si-O-C or Ti-C, and carbonitrides, such as Si-N-C. CDCs can occur in various structures, ranging from amorphous to crystalline carbon, from sp2- to sp3-bonded, and from highly porous to fully dense. Among others, the following carbon structures have been derived from carbide precursors: micro- and mesoporous carbon, amorphous carbon, carbon nanotubes, onion-like carbon, nanocrystalline diamond, graphene, and graphite. Among carbon materials, microporous CDCs exhibit some of the highest reported specific surface areas (up to more than 3000 m2/g). By varying the type of the precursor and the CDC synthesis conditions, microporous and mesoporous structures with controllable average pore size and pore size distributions can be produced. Depending on the precursor and the synthesis conditions, the average pore size control can be applied at sub-Angstrom accuracy. This ability to precisely tune the size and shapes of pores makes CDCs attractive for selective sorption and storage of liquids and gases (e.g., hydrogen, methane, CO2) and the high electric conductivity and electrochemical stability allows these structures to be effectively implemented in electrical energy storage and capacitive water desalinization.

<span class="mw-page-title-main">Silicene</span> Two-dimensional allotrope of silicon

Silicene is a two-dimensional allotrope of silicon, with a hexagonal honeycomb structure similar to that of graphene. Contrary to graphene, silicene is not flat, but has a periodically buckled topology; the coupling between layers in silicene is much stronger than in multilayered graphene; and the oxidized form of silicene, 2D silica, has a very different chemical structure from graphene oxide.

Claire Berger is a French physicist at the Georgia Institute of Technology and a Director of Research at the French National Centre for Scientific Research. Berger has co-authored about 200 publications in international journals and has a citation index of 10,880. She has won a number of prizes including the CNRS medal for Young Researcher and the Louis Ancel Prize of the French Physical Society. She was recently elected fellow of the American Physical Society.

Band-gap engineering is the process of controlling or altering the band gap of a material. This is typically done to semiconductors by controlling the composition of alloys, constructing layered materials with alternating compositions, or by inducing strain either epitaxially or topologically. A band gap is the range in a solid where no electron state can exist. The band gap of insulators is much larger than in semiconductors. Conductors or metals have a much smaller or nonexistent band gap than semiconductors since the valence and conduction bands overlap. Controlling the band gap allows for the creation of desirable electrical properties.

<span class="mw-page-title-main">Yury Gogotsi</span> Ukrainian scientist

Yury Georgievich Gogotsi is a scientist in the field of material chemistry, professor at Drexel University, Philadelphia, United States since 2000 in the fields of Materials Science and Engineering and Nanotechnology. Distinguished University and Trustee Chair professor of materials science at Drexel University — director of the A.J. Drexel Nanotechnology Institute.

A rapidly increasing list of graphene production techniques have been developed to enable graphene's use in commercial applications.

<span class="mw-page-title-main">Electronic properties of graphene</span>

Graphene is a semimetal whose conduction and valence bands meet at the Dirac points, which are six locations in momentum space, the vertices of its hexagonal Brillouin zone, divided into two non-equivalent sets of three points. The two sets are labeled K and K′. The sets give graphene a valley degeneracy of gv = 2. By contrast, for traditional semiconductors the primary point of interest is generally Γ, where momentum is zero. Four electronic properties separate it from other condensed matter systems.

<span class="mw-page-title-main">Discovery of graphene</span>

Single-layer graphene was first unambiguously produced and identified in 2004, by the group of Andre Geim and Konstantin Novoselov, though they credit Hanns-Peter Boehm and his co-workers for the experimental discovery of graphene in 1962; while it had been explored theoretically by P. R. Wallace in 1947. Boehm et al. introduced the term graphene in 1986.

Epitaxial graphene growth on silicon carbide (SiC) by thermal decomposition is a method to produce large-scale few-layer graphene (FLG). Graphene is one of the most promising nanomaterials for the future because of its various characteristics, like strong stiffness and high electric and thermal conductivity. Still, reproducible production of Graphene is difficult, thus many different techniques have been developed. The main advantage of epitaxial graphene growth on silicon carbide over other techniques is to obtain graphene layers directly on a semiconducting or semi-insulating substrate which is commercially available.

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Francesca Iacopi is an engineer, researcher and an academic. She specializes in materials and nanoelectronics engineering and is a professor at the University of Technology Sydney. She is a chief investigator of the ARC Centre of Excellence in Transformative Meta-Optical Systems, a Fellow of the Institution of Engineers Australia, and a senior member of Institute of Electrical and Electronics Engineers.

References

  1. ↑ Knight, W.D.; et al. (1984). "Electronic Shell Structure and Abundances of Sodium Clusters". Physical Review Letters . 52 (24): 2141. Bibcode:1984PhRvL..52.2141K. doi:10.1103/PhysRevLett.52.2141.
  2. ↑ Billas, I.; Chatelain, A.; de Heer, W. (1994). "Magnetism from the Atom to the Bulk in Iron, Cobalt, and Nickel Clusters". Science . 265 (5179): 1682–4. Bibcode:1994Sci...265.1682B. doi:10.1126/science.265.5179.1682. PMID   17770895. S2CID   25787167.
  3. ↑ Web of Science, retrieved 18 November 2010.
  4. ↑ de Heer, W. (1993). "The physics of simple metal clusters: experimental aspects and simple models". Reviews of Modern Physics . 65 (3): 611. Bibcode:1993RvMP...65..611D. doi:10.1103/RevModPhys.65.611.
  5. ↑ de Heer, W.; Chatelain, A.; Ugarte, D. (1995). "A Carbon Nanotube Field-Emission Electron Source". Science. 270 (5239): 1179. Bibcode:1995Sci...270.1179D. doi:10.1126/science.270.5239.1179. S2CID   179090084.
  6. ↑ Frank, S.; Poncharal, P; Wang, Z.L.; de Heer, W. (1998). "Carbon Nanotube Quantum Resistors". Science. 280 (5370): 1744–6. Bibcode:1998Sci...280.1744F. CiteSeerX   10.1.1.485.1769 . doi:10.1126/science.280.5370.1744. PMID   9624050.
  7. ↑ Dekker, C. (1999). "Carbon Nanotubes as Molecular Quantum Wires". Physics Today . 52 (5): 22. Bibcode:1999PhT....52e..22D. doi:10.1063/1.882658.
  8. 1 2 3 4 de Heer, W.A. (2009). "Early development of graphene electronics". SMARTech. hdl:1853/31270.
  9. 1 2 Chang, Kenneth (10 April 2007). "Thin Carbon Is In: Graphene Steals Nanotubes' Allure". The New York Times.
  10. ↑ Toon, John (14 March 2006). "Carbon-Based Electronics: Researchers Develop Foundation for Circuitry and Devices Based on Graphite". Georgia Tech Research News.
  11. ↑ "NIRT: Electronic Devices from Nano-patterned Epitaxial Graphite". National Science Foundation. 12 August 2004.
  12. ↑ Berger, C.; et al. (22 March 2004). "Two dimensional electron gas properties of ultrathin epitaxial graphite". Bulletin of the American Physical Society. A17.008.
  13. 1 2 Berger, C.; et al. (2004). "Ultrathin epitaxial graphite: Two dimensional electron gas properties and a route towards graphene based electronics". Journal of Physical Chemistry B . 108 (52): 19912. arXiv: cond-mat/0410240 . doi:10.1021/jp040650f. S2CID   848033.
  14. ↑ USpatent 7015142,Walt A. DeHeer, Claire Berger, and Phillip N. First,"Patterned thin film graphite devices and method for making same",issued 2006-03-21
  15. ↑ Baringhaus, Jens; Ruan, Ming; Edler, Frederik; Tejeda, Antonio; Sicot, Muriel; Taleb-Ibrahimi, Amina; Li, An-Ping; Jiang, Zhigang; Conrad, Edward H.; Berger, Claire; Tegenkamp, Christoph; de Heer, Walt A. (February 2014). "Exceptional ballistic transport in epitaxial graphene nanoribbons". Nature. 506 (7488): 349–354. arXiv: 1301.5354 . doi:10.1038/nature12952. ISSN   0028-0836.
  16. ↑ Makar, A. B.; McMartin, K. E.; Palese, M.; Tephly, T. R. (June 1975). "Formate assay in body fluids: application in methanol poisoning". Biochemical Medicine. 13 (2): 117–126. doi:10.1016/0006-2944(75)90147-7. ISSN   0006-2944. PMID   1.
  17. 1 2 Zhao, Jian; Ji, Peixuan; Li, Yaqi; Li, Rui; Zhang, Kaimin; Tian, Hao; Yu, Kaicheng; Bian, Boyue; Hao, Luzhen; Xiao, Xue; Griffin, Will; Dudeck, Noel; Moro, Ramiro; Ma, Lei; de Heer, Walt A. (January 2024). "Ultrahigh-mobility semiconducting epitaxial graphene on silicon carbide". Nature. 625 (7993): 60–65. arXiv: 2308.12446 . doi:10.1038/s41586-023-06811-0. ISSN   1476-4687.
  18. ↑ "APS Fellow Archive". APS. Retrieved 17 September 2020.
  19. ↑ "Scientific American 50: SA 50 Winners and Contributors". Scientific American. 12 November 2006.
  20. ↑ "Grants Awarded in 2007". W.M. Keck Foundation.
  21. ↑ "2007 Faculty Award recipients" (PDF). IBM University Research & Collaboration. 2007.
  22. ↑ "2008 Faculty Award recipients" (PDF). IBM University Research & Collaboration. 2008.
  23. ↑ Bullis, Kevin (March–April 2008). "TR10: Graphene Transistors". Technology Review. MIT.
  24. ↑ "The Nanoscience Prize" (24 September 2009) 10th International Conference on Atomically Controlled Surfaces, Interfaces, and Nanostructures. Granada, Spain.
  25. ↑ "MRS Medal Award" (1 October 2010). Materials Research Society.
  26. ↑ https://scholar.google.com/citations?user=klW4cOMAAAAJ&hl=en, current as of 20 December 2023
  27. ↑ "Nobel document triggers debate"
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