DOCSLIB.ORG

Precursor Chemistry of Tantalum and Niobium Nitride for MOCVD and ALD Applications

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Precursor Chemistry of Tantalum and Niobium Nitride for MOCVD and ALD Applications Precursor Chemistry of Tantalum and Niobium Nitride for MOCVD and ALD Applications Dissertation Arne Baunemann Precursor Chemistry of Tantalum and Niobium Nitride for MOCVD and ALD Applications Dissertation zur Erlangung der Doktorwürde der Fakultät für Chemie der Ruhr-Universität Bochum vorgelegt von Diplom-Chemiker Arne Baunemann Referenten Prof. Dr. Roland A. Fischer Prof. Dr. William S. Sheldrick II Die vorliegende Arbeit entstand in der Zeit von Oktober 2003 bis Oktober 2006 am Lehrstuhl für Anorganische Chemie II der Ruhr-Universität Bochum Meinem Mentor und Betreuer, Professor Dr. Roland A. Fischer möchte ich an dieser Stelle meinen außerordentlichen Dank zuteil werden lassen. Ohne seine inspirierende Vorlesung im ersten Semester hätte ich nicht den Weg in die Chemie gefunden. Während meines gesamten Studiums hat er mir jederzeit mit Rat und Tat zur Seite gestanden und mich in allen Plänen - ohne Einschränkungen - unterstützt. Diese Erfahrungen haben mich zutiefst für mein weiteres Leben geprägt. III “Contradictions do not exist. Whenever you think that you are facing a contradiction, check your premises. You will find that one of them is wrong.” (Ayn Rand in “Atlas Shrugged”, 1957) Meinen Eltern und Carmen IV Acknowledgements Danksagung Juniorprof. Dr. Anjana Devi Anjana und Harish danke ich außerordentlich für die & Dr. Harish Parala Unterstützung in Form von konstruktiver Kritik in vielen Bereichen und der Unterstützung bei XRD und TG/DTA Messungen. Dr. Christian Gemel Christian danke ich für den wertvollen chemischen Input, den er mir in den letzten Jahren gegeben hat. Marie-Kathrin Schröter Nana danke ich für die Unterstützung und den gemeinsamen Spaß in den letzten acht Jahren, die wir fast tagein-tagaus miteinander verbracht haben. Awesome. Martin Lemberger Martin hat es mit nahezu unermüdlichem Eifer geschafft, mir einen gewissen Einblick in das Mysterium der Elektrotechnik zu geben. Vielen Dank für die Kooperation im Rahmen des DFG. Stephan Hermes & Andreas Stephan und Andreas danke ich für die kreative Kempter Unterstützung, wenn es darum ging, neue Wege zu gehen und ganz besonders für die Showvorlesung. Denise Zacher Danke für die Motivation, Hilfe bei Syntheseproblemen und ein immer offenes Ohr. Sabine Masukowitz Vielen Dank für die Unterstützung in allen organisatorischen Fragen und bei dem Umgang mit dem RUB’schen Büroapparat. Stephan Spöllmann Stephan danke ich für die vielen Experimente, die er mit Lucy alias Aixtron 200 FE durchgeführt hat. Manuela Winter Manuela danke ich für die Lösung von vielen, vielen Kristallstrukturen und die Berücksichtung meiner wirren Wünsche für die Bezeichnung der Atome. Kai Richter Kai danke ich für die tatkräftige Unterstützung bei der Synthese von Schwefel und anderen nützlichen Dingen. Dr. Rolf Neuser Herrn Neuser danke ich für die SEM- und EDX Messungen. Prof. Dr. Martin Feigel und Ihnen danke ich für die Unterstützung bei dem Lösen von Priv. Doz. Dr. Iris Müller schwierigen NMR-Spektren und Kristallstrukturen. Prof. Dr. Lauri Niinistö & Vielen Dank für die nette und herzliche Aufnahme an der Jaako Niinistö Helsinki University of Technology. V Acknowledgements Prof. Dr. Jin-Hio Boo & Vielen Dank für die sehr gastfreundliche Aufnahme an der Jin-Ho Park Sungkyunkwan University. H.C. Starck GmbH Ich danke Herrn Dr. Stephan Kirchmeyer, Herrn Dr. Knud Reuter und Herrn Gerd Passing für die materielle und wissenschaftliche Unterstützung währende der Promotion. Desweiteren möchte ich mich bei meinem gesamten Lehrstuhl für die schöne Zeit in der Gruppe bedanken. Dazu gehören Saeed Amirjalayer, Dr. Raghunandan Bhakta, Beatrice Buchin, Thomas Cadenbach, Mirza Cokoja, Rolf Deibert, Daniel Esken, Lina Freitag, Dr. Eliza Gemel, Malte Hellwig, Ursula Herrmann, Todor Hikov, Heike Kampschulte, Andreas Kempter, Dr. Jayaprakash Khanderi, Dr. Emmanuel Lamouroux, Dr. Eva Maile, Mikhail Meilikhov, Andrian Milanov, Maike Müller, Daniel Rische, Dr. Rochus Schmid, Felicitas Schröder, Dr. Jelena Sekulic, Stephan Spöllmann, Tobias Thiede, Dr. Maxim Tafipolsky, Tim Wilmsen, Manuela Winter, Dr. Wenhua Zhang und Xiaoning Zhang. VI Table of contents Table of contents Chapter 1 Introduction and motivation 1 1.1 Motivation and goals 2 1.2 Phases of group(V) nitrides and their properties 4 1.3 Applications of tantalum and niobium nitrides 7 1.4 Techniques for deposition of thin films via gasphase 11 1.4.1 Physical Vapor Deposition (PVD) 11 1.4.2 Metal Organic Chemical Vapor Deposition (MOCVD) 12 1.4.3 Atomic Layer Deposition (ALD) 16 Chapter 2 State of the art in research and motivation 19 2.1 Previously reported MOCVD experiments for group(V) nitrides 19 2.1.1 MOCVD of tantalum nitride 20 2.1.2 Conclusions of past reports about the MOCVD of tantalum nitride 24 2.1.3 MOCVD of niobium nitride 28 2.2 Previously reported ALD experiments for group(V) nitrides 29 2.2.1 ALD of tantalum nitride 29 2.2.2 ALD of niobium nitride 32 Chapter 3 Starting compounds and their synthesis 34 3.1 Synthesis of mixed amido / imido compounds of tantalum and niobium 34 3.1.1 Single crystal X-ray analysis of S8, S3 and the hydrolyzed form of S3 (S3’) 36 3.1.2 Thermal properties of the compounds S4-S9 39 3.2 Ligand synthesis 41 3.2.1 Synthesis of N-trimethylsilyl-N’,N’-bisdimethylhydrazine (Htdmh) 42 Chapter 4 Hydrazido based precursors of tantalum 44 4.1 Hydrazine derivatives as useful ligands for new MOCVD and ALD precursors 44 4.2 Synthesis of amido / imido / hydrazido complexes A1-A3 by transamination reactions 46 4.2.1 Synthetic route, purity and properties of the compounds A1-A3 46 4.2.2 Spectroscopic analysis of the compounds A1-A3 48 4.2.3 Single crystal X-ray analysis of A1 49 4.2.4 Thermal analysis of A1-A3 in respect to MOCVD / ALD 50 4.3 Destructive transamination reactions of A1-A3 with N,N-dimethyl-hydrazine (Hdmh) 52 4.3.1 Single crystal X-ray analysis of a hydrolyzed tantalum-dmh complex 54 4.4 Reactions of TaCl5 and [TaCl3(N-t-Bu)py2] with lithiated hydrazine derivatives 57 Chapter 5 Guanidinato based precursors of tantalum and niobium 60 5.1 Types of guanidinate ligands in complexes and their synthesis 60 5.2 Potential of guanidinate(-1) ligands for precursor chemistry 64 5.3 Synthesis of amido / imido / guanidinato compounds of tantalum B1-B8 65 5.3.1 Synthetic route, purity and properties of the compounds B1-B8 65 5.3.2 Spectroscopic analysis of the compounds B1-B8 68 5.3.3 Single crystal X-ray analysis of B1-B5 and B7 74 VII Table of contents 5.4 Synthesis of amido / imido / guanidinato compounds of niobium C1-C4 83 5.4.1 Synthetic route, purity and properties of the compounds C1-C4 83 5.4.2 Spectroscopic analysis of the compounds C1-C4 84 5.4.3 Single crystal X-ray analysis of C1 and C2 85 5.5 Thermal analysis of B1-B8 and C1-C4 in respect to MOCVD / ALD 87 5.6 Investigations of the thermal decomposition of B1-B3 91 Chapter 6 MOCVD of tantalum nitride 93 6.1 Presentation of the MOCVD reactors utilized in this work 94 6.1.1 Bubbler design – Enhancement of precursor evaporation 98 6.2 Deposition experiments with simple amido / imido tantalum precursors 99 6.2.1 Depositions with [Ta(NEtMe)3(N-t-Bu)] (S5) in the selfbuilt horizontal reactor 100 6.2.2 Depositions with [Ta(NEt2)3(N-t-Bu)] (S6) in the Aixtron 200 RF reactor 104 6.2.3 Depositions with [Ta(NEt2)3(N-t-Bu)] (S6) in the 150 mm wafer reactor 112 6.2.4 Depositions with [Ta(NMeEt)3(N-t-Bu)] (S5) in the 150 mm wafer reactor 113 6.2.5 Conclusions for the use of mixed amido / imido tantalum precursors 114 6.3 Deposition experiments with mixed amido / imido / hydrazido tantalum precursors 115 6.3.1 Depositions in the selfbuilt horizontal cold wall reactor 115 6.3.2 Depositions with [Ta(NMeEt)2(tdmh)(N-t-Bu)] (A2) in the 150 mm wafer reactor 118 6.3.3 Conclusions for the use of mixed amido / imido / hydrazido tantalum precursors 119 6.4 Deposition experiments with mixed amido / imido / guanidinato tantalum precursors 121 6.4.1 Depositions with B2 in the selfbuilt horizontal reactor 121 6.4.2 Depositions with B2 in the LI – MOCVD reactor Aixtron 200 FE 125 6.4.3 Conclusions for the use of mixed amido / imido / guanidinato tantalum precursors 127 6.5 Electrical characterization of TaN films for MOS-gate structures at the FIIS (Erlangen) 128 Chapter 7 MOCVD of niobium nitride 130 7.1 Depositions with [Ta(NMe2)3(N-t-Bu)] (S8) in the selfbuilt horizontal reactor 130 7.2 Depositions with C1 in the selfbuilt horizontal reactor 133 Chapter 8 ALD of metal (oxo) nitride materials 136 8.1 Presentation of the ASM F120 ALD reactor 136 8.2 ALD experiments in a well adjusted F-120 reactor (Finland) 138 8.3 Installation of the F120 reactor in Bochum and first results 140 8.3.1 Depositions with S5 in reactor setup I 140 8.3.2 Depositions of Al2O3, TaON and NbON in reactor setup II 142 8.4 Conclusions for the ALD of tantalum and niobium nitride materials 145 Chapter 9 Summary and outlook 147 Chapter 10 Experimental 154 10.1 Analytical characterization of the precursors 154 10.2 Thin films analysis and instruments 155 10.3 Details to MOCVD and ALD experiments 161 10.3.1 Wafer treatment 161 VIII Table of contents 10.3.2 Handling of the selfbuilt reactor 161 10.3.3 Handling of the ASM F-120 Reactor 162 10.4 General comments on synthesis and characterization 162 10.5 Synthesis of the starting compounds S1-S11 164 10.5.1 Synthesis of the chloro-containing intermediate compounds S1 - S3 164 10.5.2 Synthesis of the mixed amido / imido complexes S4 - S8 165 10.5.3 Synthesis of N-Trimethylsilyl-N’,N’-dimethylhydrazine 167 10.6 Synthesis involving hydrazines (A1-A5 and further
Load more

Recommended publications
  • Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides
    Article pubs.acs.org/cm Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides Wenhao Sun,†,‡ Aaron Holder,§,⊥ Bernardo Orvañanos,‡ Elisabetta Arca,§ Andriy Zakutayev,§ Stephan Lany,§ and Gerbrand Ceder*,†,‡,∥ † Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States ‡ Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States § National Renewable Energy Laboratory, Golden, Colorado 80401, United States ∥ Department of Materials Science and Engineering, Univeristy of California, Berkeley, California 94720, United States ⊥ Department of Chemical and Biological Engineering, Univeristy of Colorado, Boulder, Colorado 80309, United States *S Supporting Information ABSTRACT: Compared to oxides, the nitrides are relatively unexplored, making them a promising chemical space for novel materials discovery. Of particular interest are nitrogen-rich nitrides, which often possess useful semiconducting properties for electronic and optoelectronic applications. However, such nitrogen-rich compounds are generally metastable, and the lack of a guiding theory for their synthesis has limited their exploration. Here, we review the remarkable metastability of observed nitrides, and examine the thermodynamics of how reactive nitrogen precursors can stabilize metastable nitrogen-rich compositions during materials synthesis. We map these thermodynamic strategies onto a predictive computational search, training a data-mined
    [Show full text]
  • Spark Plasma Sintering of Tantalum Carbide and Graphene Reinforced Tantalum Carbide Ceramic Composites
    SPARK PLASMA SINTERING OF TANTALUM CARBIDE AND GRAPHENE REINFORCED TANTALUM CARBIDE COMPOSITES By AJITH KUMAR KALLURI Bachelor of Science in Mechanical Engineering VIT University Vellore, India 2010 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE December, 2012 SPARK PLASMA SINTERING OF TANTALUM CARBIDE AND GRAPHENE REINFORCED TANTALUM CARBIDE COMPOSITES Thesis Approved: Dr. Sandip P. Harimkar Thesis Adviser Dr. A. Kaan Kalkan Dr. Raman P. Singh ii ACKNOWLEDGEMENTS I would like to thank my advisor Dr. Sandip P. Harimkar for his kind advise, guidance, and patience throughout my masters. I would also be grateful to Dr. A. Kaan Kalkan and Dr. Raman P. Singh for being my committee members and their valuable suggestions throughout my thesis. I would like to convey my deepest sense of gratitude to Ashish Singh for his valuable suggestions, support, and care, Sriharsha Karumuri for his encouragement, moral support and Sudheer Bandla for his help with my thesis. I could not have completed my thesis without their help. It will take a life time to forget the precious time, love and support which they gave when in need. I would also like to thank Amy Aurilio for her help with my thesis write up. Last but not the least; I am very grateful to my parents (Ramesh Babu Kalluri and Sarada Gogineni) and my sister (Divya Sree Kalluri) for their love, support and encouragement throughout my career. Heartful thanks to my uncle Dr. Sridhar Gogineni, his wife Manasa Gogineni, my sister Neelima Kalluri and my very lovable niece Sreeja Gogineni who never let me miss home.
    [Show full text]
  • Tungsten Alkyl Alkylidyne and Bis(Alkylidene) Complexes. Their Unusual Inter-Conversion and Reactions with Phosphines, Dioxygen and Water
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 8-2005 Tungsten Alkyl Alkylidyne and Bis(Alkylidene) Complexes. Their Unusual Inter-Conversion and Reactions with Phosphines, Dioxygen and Water Laurel Anne Morton University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Chemistry Commons Recommended Citation Morton, Laurel Anne, "Tungsten Alkyl Alkylidyne and Bis(Alkylidene) Complexes. Their Unusual Inter- Conversion and Reactions with Phosphines, Dioxygen and Water. " PhD diss., University of Tennessee, 2005. https://trace.tennessee.edu/utk_graddiss/2258 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Laurel Anne Morton entitled "Tungsten Alkyl Alkylidyne and Bis(Alkylidene) Complexes. Their Unusual Inter-Conversion and Reactions with Phosphines, Dioxygen and Water." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Chemistry. Ziling (Ben) Xue, Major Professor We have read this dissertation and recommend its acceptance: Craig E. Barnes, Charles D. Feigerle, X. Peter Zhang, John R. Collier Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a dissertation written by Laurel Anne Morton entitled "Tungsten Alkyl Alkylidyne and Bis(Alkylidene) Complexes.
    [Show full text]
  • Ultra-Thin Niobium Nitride Films for Hot Electron Bolometer and Thz Applications
    THESIS FOR THE DEGREE OF LICENTIATE OF ENGINEERING Ultra-thin Niobium Nitride Films for Hot Electron Bolometer and THz Applications SASCHA KRAUSE Group for Advanced Receiver Development Department of Earth and Space Science CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden 2016 i Ultra-thin Niobium Nitride Films for Hot Electron Bolometer and THz Applications SASCHA KRAUSE © SASCHA KRAUSE, 2016. Thesis for the degree of Licentiate of Engineering Group for Advanced Receiver Development Department of Earth and Space Science Chalmers University of Technology SE-412 96 Gothenburg Sweden Telephone + 46 (0)31-772 1000 Cover: Upper left corner: The Atacama Path Finder Experiment representing the exploration of space in the submillimeter and THz frequency range, upper right corner: HRTEM image of ultra-thin NbN film that is grown onto a GaN buffer-layer in an epitaxial manner, lower left corner: SEM image of the employed HEB used for measuring the phonon escape time, lower right corner: Resistance versus temperature behavior of the investigated ultra-thin NbN films which were grown onto different buffer-layers and substrates. [Printed by Chalmers Repro Service] Gothenburg, 2016 ii Ultra-thin Niobium Nitride Films for Hot Electron Bolometer and THz Applications SASCHA KRAUSE Group for Advanced Receiver Development Department of Earth and Space Science Chalmers University of Technology Gothenburg, Sweden 2016 Abstract The part of the electromagnetic spectrum between microwaves and infrared, also known as the terahertz band, is of particular interest for radio astronomy. The radiation intensity of the cold universe peaks at this frequency band, thus defining the demand on sensitive low-noise instruments in this particular frequency range.
    [Show full text]
  • Development of a Nbn Deposition Process for Superconducting Quantum Sensors
    1 Development of a NbN Deposition Process for Superconducting Quantum Sensors D. M. Glowacka, D. J. Goldie, S. Withington, H. Muhammad, G. Yassin , and B. K. Tan occurs with the addition of the reactive gas during sputtering, Abstract— We have carried out a detailed programme to which in turn affects stoichiometry. It is very important to explore the superconducting characteristics of reactive DC- quantify the location of the best operating point, and this magnetron sputtered NbN. The basic principle is to ignite a requires a careful study of the effects of deposition conditions. plasma using argon, and then to introduce a small additional Thakoor et al. [2] found that high-Tc NbN films were nitrogen flow to achieve the nitridation of a Nb target. Subsequent sputtering leads to the deposition of NbN onto the deposited at the point where the total sputter pressure started host substrate. The characteristics of a sputtered film depend on to increase rapidly with increasing nitrogen flow. In this paper, a number of parameters: argon pressure, nitrogen flow rate and we outline work that we have done to create a high-yield time-evolution profile, substrate material, etc. Crucially, the highly-reproducible deposition process for high-Tc NbN. We hysteresis in the target voltage as a function of the nitrogen flow also briefly describe work on realising and measuring can be used to provide a highly effective monitor of nitrogen resonators of the kind that would be suitable for a KID array consumption during the reactive process. By studying these dependencies we have been able to achieve highly reproducible operating at 3.5 K in an easy-to-use closed-cycle refrigerator.
    [Show full text]
  • Synthesis and Photoelectrochemical Characterization of Tantalum Oxide Nanoparticles and Their Nitrogen Derivatives
    University of Nevada, Reno Synthesis and Photoelectrochemical Characterization of Tantalum Oxide Nanoparticles and their Nitrogen Derivatives A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical engineering by Vijay Khanal Dr. Vaidyanathan (Ravi) Subramanian – Advisor August 2019 The Graduate School We recommend that the dissertation prepared under our supervision by VIJAY KHANAL Entitled Synthesis and Photoelectrochemical Characterization of Tantalum Oxide Nanoparticles and their nitrogen Derivatives Be accepted in partial fulfillment of the Requirements for the degree of DOCTOR OF PHILOSOPHY Vaidyanathan (Ravi) Subramanian, Ph.D., Advisor Dhanesh Chandra, Ph.D., Committee Member Alan Fuchs, Ph.D., Committee Member Victor Vasquez, Ph.D., Committee Member Mario A. Alpuche, Ph.D. Graduate School Representative David W. Zeh, Ph.D., Dean, Graduate School August 2019 i ABSTRACT This work presents a surfactant-mediated approach for the synthesis of Ta2O5 nanopar- 2 1 2 1 ticles with a very high surface area (41 m g− vs. 1.6 m g− for commercial equivalent), and their subsequent nitridation to yield two distinct nitrogen derivatives: TaON and Ta3N5. Excellent photocatalytic efficiency of Ta2O5 toward photodegradation of methy- lene blue and NOx removal is reported. Ta3N5 shows significant photoconversion of methylene blue attributable to its lowered bandgap and high adsorption capability of MB molecules on its surface. A new method for simplifying the existing synthesis protocols of single phase Tantalum oxynitride (TaON) was devised. Series of photoelectrochemical characterization shows that the newly synthesized TaON can significantly enhance the photoassisted charge generation, separation, and transportation compared to the parent oxide (Ta2O5).
    [Show full text]
  • A Case for Capacitor Grade Sintered Tantalum
    Bull. Mater. Sci., Vol. 28, No. 4, July 2005, pp. 305–307. © Indian Academy of Sciences. Powder metallurgical processing and metal purity: A case for capacitor grade sintered tantalum G S UPADHYAYA Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur 208 016, India Abstract. The paper reviews the role of sintered tantalum as volumetric efficient electrical capacitor. Powder characteristics and sintering aspects are discussed. The role of impurities in influencing the electrical properties has been described. Today’s driving force behind the Ta market is the use of surface mounted versions known as chip types, for applications requiring a wide range of operational temperature, such as automotive electronics. Keywords. Tantalum powder; sintering; capacitor. 1. Introduction tantalum powder. The pellet, with an attached tantalum lead wire, is electrochemically oxidized to grow a thin Many products and devices are being manufactured through layer of insulating tantalum oxide on the surface of the powder metallurgy route, because of many associated tantalum. Next, the anodized pellet is impregnated with advantages (Upadhyaya 1997). The purity of the starting manganese nitrate which is then thermally decomposed to metal or ceramic powder is of significance in controlling leave or deposit semiconducting manganese dioxide on the microstructure/properties/processing and performance the tantalum oxide. These processes create the conduc- of such products. The major methods of production of tor (Ta)/insulator(Ta2O5)/conductor(MnO2) configuration metal powders are: chemical, physical and mechanical. needed for a capacitor. Finally, the unit is encapsulated Tantalum is used mainly as a corrosion resistant metal usually in the chip configuration.
    [Show full text]
  • Novel Semiconductor-Superconductor Structure Features Versatile Gallium Nitride 8 March 2018, by Tom Fleischman
    Novel semiconductor-superconductor structure features versatile gallium nitride 8 March 2018, by Tom Fleischman niobium nitride (NbN), a proven superconductor material used in quantum communications, astronomy and a host of other applications. The group's paper, "GaN/NbN Epitaxial Semiconductor/Superconductor Heterostructures," is being published online March 8 in Nature. Former postdoctoral researcher Rusen Yan and current postdoc Guru Khalsa are co-lead authors. Other key contributors were Grace Xing, the Bandgap, lattice constant, crystallinity and Richard Lundquist Sesquicentennial Professor in superconductivity in epitaxial NbNx on SiC. a, Bandgap ECE and MSE, and David Muller, the Samuel B. versus lattice constant for select nitride semiconductors as well as for SiC. b, Cross-section HAADFSTEM Eckert Professor of Engineering in the Department images in black/white (left) and false-colour (right) of of Applied and Engineering Physics. 5-nm NbNx grown on an SiC substrate with a AlN capping layer. c, Resistance versus temperature The method for combining the two materials – (normalized to the resistance at 16K), showing the molecular beam epitaxy (MBE), essentially spray superconducting phase transition of 5-nm (red) and painting of gallium and nitrogen atoms onto the 35-nm (blue) . Credit: Nature (2018). DOI: NbN in a vacuum environment – creates an 10.1038/nature25768 extremely clean interface and is key to the success of the novel structure. This advance, the group says, opens up a range of Silicon has been the semiconductor material of possibilities that can now combine the macroscopic choice for electronics pretty much since the quantum effects of superconductors with the rich transistor effect was first observed and identified electronic and photonic properties of group III- nearly 80 years ago.
    [Show full text]
  • Discovery of Superconductivity in Hard Hexagonal Ε-Nbn
    BNL-111904-2016-JA Discovery of Superconductivity in Hard Hexagonal ε-NbN Yongtao Zou1,2, Xintong Qi3, Cheng Zhang4, Shuailing Ma1, Wei Zhang5, Ying Li2, Ting Chen3, Xuebing Wang3, Zhiqiang Chen2, David Welch4,6, Pinwen Zhu1, Bingbing Liu1, Qiang Li4, Tian Cui1 & Baosheng Li2 1State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, 130012, China. 2Mineral Physics Institute, State University of New York, Stony Brook, N.Y. 11794, United States. 3Department of Geosciences, State University of New York, Stony Brook, N.Y. 11794, United States. 4Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, N.Y. 11973, United States. 5School of Science, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China. 6Department of Materials Science and Engineering, State University of New York, Stony Brook, N.Y. 11794, United States. *Correspondence and requests for materials should be addressed to Y. Z. (E-mail: [email protected] ), Y. L . (E-mail:[email protected]) **The current ultrasonic, magnetization and electrical resistivity measurements were performed in the U. S. when Yongtao Zou was working at the State University of New York (Stony Brook). Since the discovery of superconductivity in boron-doped diamond with a critical temperature (TC) near 4 K, great interest has been attracted in hard superconductors such as transition-metal nitrides and carbides. Here we report the new discovery of superconductivity in polycrystalline hexagonal ε-NbN synthesized at high pressure and high temperature. Direct magnetization and electrical resistivity measurements demonstrate that the superconductivity in bulk polycrystalline hexagonal ε-NbN is below ~11.6 K, which is significantly higher than that for boron-doped diamond.
    [Show full text]
  • Ligand-Based Reduction of CO2 to CO Mediated by an Anionic Niobium Nitride Complex
    Ligand-Based Reduction of CO2 to CO Mediated by an Anionic Niobium Nitride Complex The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Silvia, Jared S., and Christopher C. Cummins. “Ligand-Based Reduction of CO2 to CO Mediated by an Anionic Niobium Nitride Complex.” Journal of the American Chemical Society 132.7 (2010) : 2169-2171. As Published http://dx.doi.org/10.1021/ja910445r Publisher American Chemical Society Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/65162 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Ligand-Based Reduction of CO2 to CO Mediated by an Anionic Niobium Nitride Complex Jared S. Silvia and Christopher C. Cummins Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139 RECEIVED DATE (automatically inserted by publisher); E-mail: [email protected] There are several motivations for producing chemicals from Scheme 1 CO2 whenever possible, and in particular, CO is a promising target being both a versatile chemical precursor and a fuel.1 Reducing metal complexes capable of O-atom abstraction from CO2 typically lead to the formation of strong metal- oxygen bonds that represent a challenge to catalytic turnover.2 In a special case for which the binding of CO2 evidently involves insertion into a Cu–B linkage, catalytic turnover producing CO was accomplished by taking advantage of the ultimate delivery of oxygen into a stable B–O–B reservoir.3 This is to be compared with electrocatalytic methods for CO2 reduction to CO in systems that likely involve a direct interaction between CO2 and the metal center at some point in the catalytic cycle.4 Another commonly observed trend in metal-mediated CO2 reduction is disproportionation reactivity 2– leading to the formation of CO and CO3 , highlighted by the reaction of Li2[W(CO)5] with CO2 to give W(CO)6 and 5 Li2CO3.
    [Show full text]
  • This Thesis Has Been Submitted in Fulfilment of the Requirements for a Postgraduate Degree (E.G
    This thesis has been submitted in fulfilment of the requirements for a postgraduate degree (e.g. PhD, MPhil, DClinPsychol) at the University of Edinburgh. Please note the following terms and conditions of use: This work is protected by copyright and other intellectual property rights, which are retained by the thesis author, unless otherwise stated. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Development of a High Temperature Sensor Suitable for Post-Processed Integration with Electronics Aleksandr Tabasnikov A thesis submitted for the degree of Doctor of Philosophy The University of Edinburgh 2016 Declaration of originality I declare that this thesis has been composed by me, the work is my own, and it has not been submitted for any other degree or professional qualification. Research recorded was carried out by me except as specified below: X-ray diffraction measurement results obtained using X-ray diffractometer Siemens D5000 were collected by Richard Yongqing Fu and his students Jimmy Zhou and Chao Zhao at the University of West of Scotland. Measurement results are analysed in section 4.4.6 of Chapter 4 and have been jointly published in 2014 (DOIs: 10.1109/ICMTS.2014.6841491).
    [Show full text]
  • Surface Modification of G-C3N4 by Hydrazine: Simple Way for Noble-Metal Free Hydrogen Evolution Catalysts
    Surface modification of g-C3N4 by hydrazine: Simple way for noble-metal free hydrogen evolution catalysts Item Type Article Authors Chen, Yin; Lin, Bin; Wang, Hong; Yang, Yong; Zhu, Haibo; Yu, Weili; Basset, Jean-Marie Citation Surface modification of g-C3N4 by hydrazine: Simple way for noble-metal free hydrogen evolution catalysts 2015 Chemical Engineering Journal Eprint version Post-print DOI 10.1016/j.cej.2015.10.080 Publisher Elsevier BV Journal Chemical Engineering Journal Rights NOTICE: this is the author’s version of a work that was accepted for publication in Chemical Engineering Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Chemical Engineering Journal, 2 November 2015. DOI: 10.1016/ j.cej.2015.10.080 Download date 03/10/2021 23:51:44 Link to Item http://hdl.handle.net/10754/581797 Accepted Manuscript Surface modification of g-C3N4 by hydrazine: Simple way for noble-metal free hydrogen evolution catalysts Yin Chen, Bin Lin, Hong Wang, Yong Yang, Haibo Zhu, Weili Yu, Jean-marie Basset PII: S1385-8947(15)01491-6 DOI: http://dx.doi.org/10.1016/j.cej.2015.10.080 Reference: CEJ 14356 To appear in: Chemical Engineering Journal Received Date: 18 June 2015 Revised Date: 9 October 2015 Accepted Date: 26 October 2015 Please cite this article as: Y. Chen, B. Lin, H. Wang, Y.
    [Show full text]