DOCSLIB.ORG

Methods for the ICP-OES Analysis of Semiconductor Materials Calynn Morrison, Haochen Sun, Yuewei Yao, Richard A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Methods for the ICP-OES Analysis of Semiconductor Materials Calynn Morrison, Haochen Sun, Yuewei Yao, Richard A pubs.acs.org/cm Methods/Protocols Methods for the ICP-OES Analysis of Semiconductor Materials Calynn Morrison, Haochen Sun, Yuewei Yao, Richard A. Loomis,* and William E. Buhro* Cite This: Chem. Mater. 2020, 32, 1760−1768 Read Online ACCESS Metrics & More Article Recommendations *sı Supporting Information ABSTRACT: The techniques employed in the compositional analysis of semiconductor materials by inductively coupled plasma optical emission spectroscopy (ICP-OES) dramatically influence the accuracy and reproducibility of the results. We describe methods for sample preparation, calibration, standard selection, fi C). and data collection. Speci c protocols are suggested for the analysis of II−VI compounds and nanocrystals containing the elements Zn, Cd, S, Se, and Te. We expect the methods provided will apply more generally to semiconductor materials from other families, such as to III−V and IV−VI nanocrystals. o legitimately share published articles. ■ INTRODUCTION lighter or volatile elements, degrade the surface, or change the oxidation state and crystal structures during the measure- Determination of the stoichiometries of semiconductor − ment.20 22 Difficulties determining exact stoichiometries have nanocrystals is a key aspect of their characterization. Most ff standard syntheses afford nanocrystals having a superstoichio- been reported in XPS, with up to 46% di erence between fi metric layer of metal cations at their surfaces, such that the initial and nal measurements of metal ions in samples during − fi 22 metal-to-nonmetal ratio M/E exceeds one.1 6 The excess depth pro ling. Some techniques, such as XRF, require that “ fi charge from the superstoichiometric cations is counterbalanced samples must be homogeneous and meet in nite thickness 23 by surface-bound anionic ligands. Such nonstoichiometric requirements” in order to produce accurate results. Ligand semiconductor nanocrystals may be interconverted with exchange or surface-chemistry experiments may only result in stoichiometric nanocrystals having charge-neutral surface differences of a single monolayer of atoms between ligation.2,4 Thus, the core stoichiometries of semiconductor nanostructures,2,4,12,24 and thus, beam-analysis techniques nanocrystals are variable and dependent on the surface ligation could yield stoichiometries that deviate from actuality. and nanocrystal size. Understanding and controlling the Errors in composition similar to those in beam techniques Downloaded via WASHINGTON UNIV on June 24, 2020 at 16:36:41 (UT surface chemistry benefits from the precise determination of often accompany digestion-requisite techniques. The forma- nanocrystal core stoichiometry. tion of volatile products of acid digestion results in losses before Compositional analyses of semiconductor nanocrystals have the measurement.25,26 However, by altering the digestion and been conducted by X-ray photoelectron spectroscopy sample-preparation method, volatile elements and surface See https://pubs.acs.org/sharingguidelines for options on how t − − (XPS),7 10 Rutherford back scattering (RBS),1,2,7,8,11 13 components may be retained for measurement, as we 14 atomic-absorption spectroscopy, inductively coupled plasma demonstrate in this paper. Analyses performed by ICP-OES, 3,15,16 mass spectrometry (ICP-MS), inductively coupled ICP-MS, and FAAS are total-composition measurements. 6,15,17,18 plasma optical-emission spectroscopy (ICP-OES), X- Because the samples are digested prior to analysis, particle fl 19 ray uorescence spectroscopy (XRF), and energy-dispersive size or sample thickness is irrelevant. ICP-OES and ICP-MS X-ray spectroscopy (EDS) using a transmission electron 6 are capable of detecting concentrations in the parts per million microscope (TEM). These techniques can be divided into (mg/L) and parts per billion range, respectively.25 The two categories: “beam techniques”, which include XPS, RBS, “ ” detection limits for S and Se, for example, may be as low as XRF, and EDS, and digestion-requisite analyses , with ICP- 0.3 mg/L and 0.2 mg/L, respectively.27 ICP techniques are OES, ICP-MS, and flame atomic absorption spectroscopy (FAAS) requiring that samples be digested prior to analysis. Whileeachanalysismethodbringsadvantagesand Received: January 20, 2020 disadvantages, accurate and precise determination of lighter Revised: February 21, 2020 elements or volatile components of semiconducting materials Published: February 21, 2020 can be challenging regardless of the analytical technique employed. In the case of beam techniques, high-energy photons, electrons, or ions strike the material and may eject © 2020 American Chemical Society https://dx.doi.org/10.1021/acs.chemmater.0c00255 1760 Chem. Mater. 2020, 32, 1760−1768 Chemistry of Materials pubs.acs.org/cm Methods/Protocols capable of analyzing upward of 70 elements simultaneously. Ultrapure water was obtained from a Millipore Direct-Q UV- With multiple emission wavelengths per element, interferences 3 filtration system. from spectral overlaps can generally be overcome. ICP-OES Polypropylene and high-density polyethylene screw-cap also offers the convenience to the user of high sample centrifuge tubes were obtained from Corning and VWR throughput. (Figure S1). The 1000 μL solvent-resistant Nichiryo Nichipet In the majority of studies reporting the stoichiometries of EX Plus II and Eppendorf ResearchPlus Micropipettes were semiconductor nanocrystals cited above, the measured M/E employed during ICP-OES sample preparation procedures. ratios have fallen in the range of 1.0−1.8,1,3,7,9,13,15,16,19 and in Analyses were conducted using a PerkinElmer ICP-OES PE about a third of these studies the determined values were Optima 7300DV with Syngistix for ICP, Version 2.0.0.22336 larger.6,14,17,18 Interestingly, all but one of these latter studies software. Detailed instrument settings can be found in Table employed a digestion technique prior to analysis. In the S1. specific case of zinc blende (ZB) CdSe nanoplatelets, four- monolayer specimens with an expected Cd/Se ratio of 1.25 ■ PROCEDURE 15 were analyzed for 1.80 ± 0.07, and five-monolayer specimens Estimation of Concentration from Synthesis. Analyte 28 with an expected Cd/Se ratio of 1.20 were analyzed for 1.72 solutions were ultimately prepared in the concentration range 15 ± 0.11, by ICP-OES. (The expected Cd/Se ratios are taken of 0.5−20 mg/L (see Note S1 in the Supporting Information). from an analysis of ZB CdS nanoplatelets having the same This required estimation of the amount of semiconductor numbers of monolayers.28) While these measured ratios are compound contained in an analytical sample. We assumed close to expectation, they are higher, matching the outcomes of 100% yield in a given semiconductor nanocrystal synthesis, on most of our initial efforts at ICP-OES analysis. These the basis of the limiting reagent. The following example is 29,30 observations and the experiences conveyed to us by others given. In a typical synthesis of {CdSe[n-octylamine]0.53} · motivated us to conduct a thorough investigation of the ICP- quantum belts (QBs), Cd(OAc)2 2H2O (0.039 g, 1.5 mmol) OES analysis of semiconductor materials. and selenourea (0.029 g, 2.4 mmol) were allowed to react in n- · The ICP-OES method detailed in this paper was developed octylamine (3.825 g), making Cd(OAc)2 2H2O the limiting using samples with known or strong theoretical bases for reagent.31 The total mass of the crude reaction mixture was compositions, and protocols were optimized to produce 3.893 g. reproducible results that could be compared to the expected An aliquot (0.157 g, 200 μL) was withdrawn from the values. We report results for four samples of semiconductor reaction mixture, constituting 4% of the mixture and − nanocrystals, one nanocluster, and one molecular compound as containing 4% of the original cadmium (6.6 × 10 4 g, 5.8 test cases. μmol). This aliquot was ultimately digested in hydrogen We identify several pitfalls associated with conventional peroxide (500 μL) and nitric acid (500 μL) to produce a ICP-OES analysis. We offer suggestions for improving concentrated digestion solution. The estimated Cd and Se reproducibility and accuracy in methods for sample digestion, concentrations in this solution were therefore 660 mg/L. As calibration-curve construction, and emission-line and calibra- described below, aliquots of the concentrated digestion tion-standard selection. We provide specific protocols for the solution were diluted to 10.00 mL, to produce analytical analysis of compounds and nanocrystals containing cadmium, solutions having Cd-analyte concentrations of 3.3−13.1 mg/L, zinc, sulfur, selenium, and tellurium, which we expect to apply which were within the desired range for analysis. more generally to the analysis of other semiconductor General Sample Preparation and Digestion. An aliquot materials, such as InP and PbS. We demonstrate that of a nanocrystal dispersion estimated to yield an analyte seemingly small variations in sample preparation, calibration, solution with a final concentration below 20 mg/L (see above) and data collection can have a large impact on the reliability of was purified by three centrifugation−washing cycles using the results. centrifugation at 2000 rpm for 3 min, 2 mL of toluene, and a borosilicate test tube in each cycle, each time disposing of the ■ MATERIALS supernatant to remove excess organic material and unreacted precursors. The pellet obtained from the third centrifugation The following nanomaterials were prepared as described in step was then suspended in isopropanol or ethanol, which are previous reports: {CdSe[n-octylamine]0.53} quantum belts solvents compatible with polypropylene and high-density 31 4 33 (QBs), {CdSe[Cd(oleate)2]0.19}QBs, [(CdSe)13(n- polyethylene (HDPE) centrifuge tubes. The dispersion was 32 PrNH2)13] clusters, and {CdTe0.50Se0.50[oleylamine]x} and transferred to a centrifuge tube and again centrifuged (2000 26 {CdTe0.73S0.27[oleylamine]z} quantum platelets (QPs). rpm, 3 min), and the supernatant was removed. The tube was Trace-metal grade nitric acid (70%) and trace-metal grade sealed with a rubber septum and dried under vacuum via hydrogen peroxide (32%) were obtained from Millipore Sigma.
Load more

Recommended publications
  • Advance Program 2018 Display Week International Symposium
    ADVANCE PROGRAM 2018 DISPLAY WEEK INTERNATIONAL SYMPOSIUM May 22-25, 2018 (Tuesday – Friday) Los Angeles Convention Center Los Angeles, California, US Session 1: Annual SID Business Meeting Tuesday, May 22 / 8:00 – 8:20 am / Concourse Hall 151-153 Session 2: Opening Remarks / Keynote Addresses Tuesday, May 22 / 8:20 – 10:20 am / Concourse Hall 151-153 Chair: Cheng Chen, Apple, Inc., Cupertino, CA, US 2.1: Keynote Address 1: Deqiang Zhang, Visionox 2.2: Keynote Address 2: Douglas Lanman, Oculus 2.3: Keynote Address 3: Hiroshi Amano, Nagoya University Session 3: AR/VR I: Display Systems (AI and AR & VR / Display Systems / Emerging Technologies and Applications) Tuesday, May 22, 2018 / 11:10 am - 12:30 pm / Room 515A Chair: David Eccles, Rockwell Collins Co-Chair: Vincent Gu, Apple, Inc. 3.1: Invited Paper: VR Standards and Guidelines Matthew Brennesholtz, Brennesholtz Consulting, Pleasantville, NY, US 3.2: Distinguished Paper: An 18 Mpixel 4.3-in. 1443-ppi 120-Hz OLED Display for Wide-Field-of-View High-Acuity Head-Mounted Displays Carlin Vieri, Google LLC, Mountain View, CA, US 3.3: Distinguished Student Paper: Resolution-Enhanced Light-Field Near-to-Eye Display Using E-Shifting with an Birefringent Plate Kuei-En Peng, National Chiao Tung University, Hsinchu, Taiwan, ROC 3.4: Doubling the Pixel Density of Near-to-Eye Displays Tao Zhan, College of Optics and Photonics, University of Central Florida, Orlando, FL, US 3.5: RGB Superluminescent Diodes for AR Microdisplays Marco Rossetti, Exalos AG, Schlieren, Switzerland Session 4: Quantum-Dot
    [Show full text]
  • 2015 ************************* Signature
    GRANT THORNTON LLP 757 THIRD AVE NEW YORK, NY 10017 ************************* INSTRUCTIONS FOR FILING ALFRED P. SLOAN FOUNDATION FORM 8879-EO - IRS E-FILE SIGNATURE AUTHORIZATION FOR THE PERIOD ENDED DECEMBER 31, 2015 ************************* SIGNATURE... THE ORIGINAL IRS E-FILE SIGNATURE AUTHORIZATION FORM SHOULD BE SIGNED (USE FULL NAME) AND DATED BY THE TAXPAYER. FILING... RETURN YOUR SIGNED FORM 8879-EO TO: GRANT THORNTON LLP 757 THIRD AVE 3RD FLOOR NEW YORK NY 10017-2013 OVERPAYMENT OF TAX... THE RETURN SHOWS AN OVERPAYMENT OF $2,589,048. OF WHICH NONE SHOULD BE REFUNDED TO YOU AND $2,589,048. HAS BEEN APPLIED TO YOUR 2016 ESTIMATED TAX. DISTRIBUTION REQUIRED: PLEASE NOTE THAT AT LEAST $ 24710178. MUST BE DISTRIBUTED BY THE FOUNDATION BY THE END OF THE FOLLOWING FISCAL YEAR IN ORDER TO AVOID ADDITIONAL TAX ON UNDISTRIBUTED 2015 INCOME. FORM 8879-EO SERVES AS A REPLACEMENT FOR YOUR SIGNATURE THAT WOULD BE AFFIXED TO FORM 990PF IF YOU PAPER FILED YOUR RETURN. PLEASE DO NOT SEPARATELY FILE FORM 990PF WITH THE INTERNAL REVENUE SERVICE. DOING SO WILL DELAY THE PROCESSING OF YOUR RETURN. WE MUST RECEIVE YOUR SIGNED FORM BEFORE WE CAN ELECTRONICALLY TRANSMIT YOUR RETURN WHICH IS DUE ON NOVEMBER 15, 2016. WE WOULD APPRECIATE YOUR RETURNING THIS FORM AS SOON AS POSSIBLE AS THIS WILL EXPEDITE THE PROCESSING OF YOUR RETURN. THE INTERNAL REVENUE SERVICE WILL NOTIFY US WHEN YOUR RETURN IS ACCEPTED. YOUR RETURN IS NOT CONSIDERED FILED UNTIL THE INTERNAL REVENUE SERVICE CONFIRMS THEIR ACCEPTANCE, WHICH MAY OCCUR AFTER THE DUE DATE OF YOUR RETURN. ************************* IRS e-file Signature Authorization Form 8879-EO for an Exempt Organization OMB No.
    [Show full text]
  • In This Issue
    Autumn 2014 ChemLetter Volume XXXII • No. 3 Dear Friend of Chemistry, I hope this edition of the ChemLetter finds you and yours well. Since I last wrote to you we have experienced an historic loss. Professor Emeritus Benton Seymour Rabinovitch (“Rab”), who began his career at the University of Washington in the late 1940s, passed in early August at the age of 95. You will find a brief description of his life in this issue. Rab continued to be a presence in the Department long after his retirement in the mid-1980s, until very recently when his health declined. About a decade ago, I began referring to Rab as our “patriarch.” Through contribution, compounded by longevity, he gently exerted a powerful and extremely positive influence over this department. His kind and thoughtful manner, Nancy Wade Nancy Nancy Wade Nancy and commitment to diversity, contributed to the welcoming environment that we all enjoy and benefit from to this day. Rab is gone, but his contributions and influence Paul Hopkins, Chair live on. Just a week or so ago, I received an e-mail trumpeting yet another ranking of educational programs, this one from graduateprograms.com. Anyone who has studied the methods by which educational programs are ranked, be they attempts to quantify In this issue outcomes, or purely reputational, takes these rankings with a sizeable grain of salt. Nevertheless, I could not resist clicking on the link to reveal the rankings of U.S. Letter from the Chair 1 chemistry graduate programs. Imagine my surprise at finding the Department of In Memoriam 2 Chemistry at the University of Washington in the number one spot.
    [Show full text]
  • Letter from the Chair
    CHEMLETTERAUTUMN 2017 / VOLUME XXXV NO.3 LETTER FROM THE CHAIR Dear Friend of Chemistry, Since my last message to you, we have begun the new academic year, with continuing increases in undergraduate enrollment. To help us to teach these large numbers of undergraduates, we rely on the contributions of our graduate students, who serve as teaching assistants. The incoming cohort of graduate students for the 2017- 18 academic year consists of 44 students: 22 women and 22 men from top universities in the U.S. (39) and abroad (5). To recruit this group, our faculty carefully reviewed more than 600 applications from all over the world. Students are attracted to our program by the caliber of the faculty with whom they would study, the UW’s tradition of excellence, and the quality of life in the Seattle area. We have implemented a new rotation system for our first-year graduate students to get acquainted with the work and culture of research groups they may be interested in joining. The rotation at the level of $2.6 million per year for six years. This initiative will is meant to facilitate students finding a good fit with their Ph.D. enhance the strong presence of the UW in the field of materials advisor, for which the selection process will take place next quarter. science, with an emphasis on the development of nanoscale electronic materials for numerous applications, from spectral The research program to which these students will contribute conversion to spintronics. Adjunct Associate Professor Christine continues to prosper. Our faculty have been very successful in Luscombe is the co-PI and Professors David Ginger, Xiaosong Li, winning highly competitive grants to support this work from a and Assistant Professor Brandi Cossairt are participants.
    [Show full text]
  • 2019 EFRC PI Meeting Book
    2019 PI MEETING – TABLE OF CONTENTS Table of Contents FULL AGENDA .................................................................................................. 1 SPEAKER BIOGRAPHIES ....................................................................................... 4 BES EARLY CAREER NETWORK ORGANIZED EVENTS ................................................. 11 SOCIAL EXCURSIONS ....................................................................................................................... 11 SOCIAL EVENING AT DUKE’S COUNTER MONDAY, JULY 29, 2019, 7:00PM – late ................................................................................................ 11 BASEBALL GAME AT NATIONALS PARK TUESDAY, JULY 30, 2019, 7:00PM – late ................................................................................................. 11 LUNCH EVENTS .............................................................................................................................. 12 DIVERSITY IN ENERGY SCIENCE LUNCH MONDAY, JULY 29, 2019, 12:30 – 1:30 PM, EXHIBITION HALL C – LINCOLN 2, 3, AND 4 ................................ 12 ELEVATOR PITCHES AND SCIENCE SPEED DATING LUNCH TUESDAY, JULY 30, 2019, 12:35 – 1:35 PM, LINCOLN 3&4 ........................................................................ 12 BES EARLY CAREER NETWORK (ECN) REPRESENTATIVES ...................................................................... 13 GRAPHIC AGENDA .......................................................................................... 16 HOTEL
    [Show full text]
  • Arka Majumdar
    ARKA MAJUMDAR Electrical and Computer Engineering and Physics Phone: 650-906-8666 EEB-M230, Electrical and Computer Engineering Box: 352500 Email: [email protected] Seattle, WA 98195 EDUCATIONAL HISTORY Stanford University, Stanford, CA PhD, Electrical Engineering (GPA: 4/4) September, 2012 Thesis: Solid State Cavity Quantum Electrodynamics with Quantum Dots Coupled to Photonic Crystal Cavities. Stanford University, Stanford, CA MS, Electrical Engineering (GPA: 4/4) December 2009 Indian Institute of Technology, Kharagpur, India B. Tech (Hons.), Electronics and Electrical Communication Engineering (GPA: 9.8/10) May 2007 Thesis: Filter-bank Design by Trans-conductor for Sub-band ADC. EMPLOYMENT HISTORY University of Washington Electrical and Computer Engineering and Physics Department Seattle, WA, USA Washington Research Foundation Distinguished Investigator, 01/2019-present Assistant Professor, 08/2014-present Tunoptix Inc. Seattle, WA Building low-power tunable optical elements for imaging and display Co-founder, 07/2017-present Meta Company Redwood City, CA, USA Optics consultant for nanophotonic design for augmented reality glasses 08/2014-03/2016 University of Washington, Electrical Engineering Department Seattle, WA, USA Affiliate Assistant Professor, 09/2013-06/2014 Intel Labs Santa Clara, CA, USA Postdoctoral research scientist, 08/2013-08/2014 University of California, Berkeley, Physics Department Berkeley, CA, USA Dr. Arka Majumdar Curriculum Vitae 2/23/2020 6:06 PM Postdoctoral scholar, 10/2012-07/2013 AWARDS AND HONORS ECE Department
    [Show full text]
  • Alfred P. Sloan Foundation 2015 Annual Report Alfred P
    Alfred P. Sloan Foundation 2015 Annual Report alfred p. sloan foundation $ 2015 Annual Report Contents Preface II Mission Statement III 2015 Year in Review IV President’s Letter XIII 2015 Grants by Program 1 2015 Financial Review 85 Audited Financial Statements and Schedules 87 Board of Trustees 114 Officers and Staff 115 Index of 2015 Grant Recipients 116 Cover: Italian volcano, Mt. Etna, erupts. Characterizing the role volcanos play in the global carbon cycle is one of the primary research objectives of the Deep Carbon Observatory. (PHOTO COURTESY OF ALESSANDRO AUIPPA) I alfred p. sloan foundation $ 2015 Annual Report Preface The ALFRED P. SLOAN FOUNDATION administers a private fund for the benefit of the public. It accordingly recognizes the responsibility of making periodic reports to the public on the management of this fund. The Foundation therefore submits this public report for the year 2015. II alfred p. sloan foundation $ 2015 Annual Report Mission Statement The ALFRED P. SLOAN FOUNDATION makes grants primarily to support original research and education related to science, tech- nology, engineering, mathematics, and economics. The Foundation believes that these fields—and the scholars and practitioners who work in them—are chief drivers of the nation’s health and prosper- ity and that a reasoned, systematic understanding of the forces of nature and society, when applied inventively and wisely, can lead to a better world for all. III alfred p. sloan foundation $ 2015 Annual Report 2015 Year in Review Dr. Paul L. Joskow The Alfred P. Sloan Foundation administers a private fund for the benefit of the public.
    [Show full text]
  • Alexandra Velian
    1/6 ALEXANDRA VELIAN University of Washington · Department of Chemistry Box 351700, Seattle, WA 98195-1700 · 206.616.5179 · [email protected] PROFESSIONAL APPOINTMENT Assistant Professor of Inorganic Chemistry University of Washington Interests: Surface functionalization of atomically precise inorganic clusters and two dimensional crystals for cat- alytic, electronic and quantum information applications. Website: depts.washington.edu/velian 2017−present MRSEC Postdoctoral Fellow Columbia University Advisor: Prof. Colin Nuckolls 2014−2017 Research focus: Designer materials from superatomic building blocks. EDUCATION Ph.D. in Inorganic Chemistry Massachusetts Institute of Technology Advisor: Prof. Christopher C. Cummins 2009−2014 Thesis Title: Taming Reactive Phosphorus Intermediates with Organic and Inorganic Carriers Awarded “Alan Davison Prize for the Best Thesis in Inorganic Chemistry” B.S. with Honors in Chemistry California Institute of Technology Advisor: Prof. Theodor Agapie 2005−2009 Thesis Title: Mono- and Bi-metallic Complexes Supported by a Versatile Diphosphine Terphenyl Framework Advisor: Prof. Jonas C. Peters Research Focus: Tuning the luminescence in Cu2N2 diamond-core complexes AWARDS and DISTINCTIONS Cottrell Scholar Award 2021 Co-Chair, International Conference on Energy Conversion & Storage (Clean Energy Institute) 2020 JACS Young Investigators 2020 NSF CAREER Award 2019 Before UW Young Investigator Award (ACS Division of Inorganic Chemistry) 2016 Alan Davison Prize for the Best Thesis in Inorganic Chemistry (MIT) 2015 Materials Research Science & Engineering Center Fellowship (Columbia University) 2014–2016 Elected Chair, Organometallics Gordon Research Symposium 2015 Morse Travel Grant (MIT) 2013 Hannah Bradley Summer Undergraduate Research Fellow (Caltech) 2009 Milton and Rosalind Chang Scholarship (Caltech) 2006–2009 Edward W. Hughes Summer Undergraduate Research Fellow (Caltech) 2007–2008 Summer Undergraduate Research Fellowship (Caltech) 2006–2007 Diane and Henry H.
    [Show full text]
  • Call for Papers Deadline for Abstract Submission: 15 January 2019
    European Materials Research Society Spring Meeting 2019 IUMRS - ICAM International Conference on Advanced Materials May 27-31 | Acropolis Congress Centre | Nice | France Call for Papers deadline for abstract submission: 15 January 2019 www.european-mrs.com Announcement for 2019 Spring Meeting It is with great pleasure that we announce the 2019 Spring Meeting of the European Materials Research Society (E-MRS) to be held in combination with the IUMRS - ICAM International Conference on Advanced Materials from May 27 to 31 at the Acropolis Congress Centre, Nice, France In line with the previous conferences, it is expected that this event will be the largest in Europe in the field of Materials Science and Technology. Indeed, the E-MRS Spring Meeting is a major conference with over 2500 attendees coming from all over the world every year. The 2019 Spring Meeting will consist of parallel symposia with invited speakers, oral and poster presenta- tions, assorted by two plenary sessions and a number of workshops and training courses. In parallel with the technical sessions, more than 90 international exhibitors are expected to display equipment, systems, products, software, publications and services during the meeting. The high quality scientific program will address different topics organized into 28 symposia arranged in 6 clusters covering the fields of Materials for Energy; Bio- and Soft Materials; Nano-Functional Materials; 2-Di- mensional Materials; Materials, Electronics and Photonics and Modelling and Characterization. The latest scientific results will be presented and authors are invited to submit papers in the selected journals that fit the scope of each symposium. It is worth noting that the papers are peer-reviewed at a high scientific level, according to a process and timetable that are at the discretion of the symposia organizers.
    [Show full text]
  • Letter from the Chair
    CHEMLETTERAUTUMN 2015 / VOLUME XXXIII NO. 3 LETTER FROM THE CHAIR Dear Friend of Chemistry, Since my last message to you, we have begun the new academic To help us to teach these large numbers of undergraduates, we year with yet another increase in undergraduate enrollment. The rely on the contributions of our graduate students, who serve as University of Washington admissions office was surprised by the teaching assistants. The incoming cohort of graduate students for number of applicants accepting our offer of admission, so we have the 2015-16 academic year is 62 students, breaking the previous several hundred more freshmen than we expected. Unsurprisingly, record of 58. To recruit this group, our faculty carefully reviewed many of these additional students want to study science, so we nearly 700 applications from all over the world. Students are have record enrollments in introductory chemistry. attracted to our program by the caliber of the faculty with whom they would study, the UW’s tradition of excellence, and the quality Next year, these additional students will be sophomores, and will of life in the Seattle area. Many schools compete for the very best add to the burgeoning enrollment in the organic chemistry lecture of these applicants, so we encourage prospective students to and lab courses. The latter is facing a facilities bottleneck. The attend our open house events, during which they can meet our four spacious lab rooms in the new chemistry building which were faculty, see the facilities, and experience Seattle. Forty-four of these commissioned in the mid-90s were designed to accommodate new students are from 18 different U.S.
    [Show full text]
  • Yueyang Chen
    © Copyright 2021 Yueyang Chen Development of active silicon nitride nanophotonic platform with emerging materials Yueyang Chen A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Washington 2021 Reading Committee: Arka Majumdar, Chair Karl F. Böhringer Mo Li Program Authorized to Offer Degree: Electrical Engineering University of Washington Abstract Development of active silicon nitride nanophotonic platform with emerging materials Yueyang Chen Chair of the Supervisory Committee: Arka Majumdar Department of Electrical and Computer Engineering The field of integrated photonics has grown rapidly in the past few decades, with numerous applications in data communication, quantum technology and biomedical sensing. Among various emerging platforms for photonic integration, silicon nitride (SiN) has recently become an excellent candidate thanks to its low optical loss over a broad transparent window, together with the CMOS compatibility. However, most SiN photonic components demonstrated so far are passive devices for guiding photons. Further development of active components, including photon sources and nonlinear photonics components, is required for both classical and quantum applications. One promising direction is to heterogeneously integrate novel optoelectronics materials onto the SiN platform. In this thesis, I present my work on the hybrid SiN photonics platform with two emerging materials: solution-processed colloidal quantum dots (QDs) and transition metal dichalcogenides (TMD) monolayer. I focus on the fundamental study of light-matter interaction between these quantum-confined materials with the integrated SiN photonic cavities. For colloidal QDs, I demonstrate deterministic positioning of these emitters on SiN photonic crystal nanobeam cavity and observe the Purcell enhancement and saturable photoluminescence.
    [Show full text]
  • The Surface Chemistry of Metal Chalcogenide Nanocrystals
    The Surface Chemistry of Metal Chalcogenide Nanocrystals Nicholas Charles Anderson Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Science Columbia University 2014 © 2014 Nicholas C. Anderson All rights reserved ABSTRACT The Surface Chemistry of Metal Chalcogenide Nanocrystals Nicholas C. Anderson The surface chemistry of metal chalcogenide nanocrystals is explored through several interrelated analytical investigations. After a brief discussion of the nanocrystal history and applications, molecular orbital theory is used to describe the electronic properties of semiconductors, and how these materials behave on the nanoscale. Quantum confinement plays a major role in dictating the optical properties of metal chalcogenide nanocrystals, however surface states also have an equally significant contribution to the electronic properties of nanocrystals due to the high surface area to volume ratio of nanoscale semiconductors. Controlling surface chemistry is essential to functionalizing these materials for biological imaging and photovoltaic device applications. To better understand the surface chemistry of semiconducting nanocrystals, three competing surface chemistry models are presented: 1.) The TOPO model, 2.) the Non- stoichiometric model, and 3.) the Neutral Fragment model. Both the non-stoichiometric and neutral fragment models accurately describe the behavior of metal chalcogenide nanocrystals. These models rely on the covalent bond classification system, which divides ligands into three classes: 1.) X-type, 1-electron donating ligands that balance charge with excess metal at the nanocrystal surface, 2.) L-type, 2-electron donors that bind metal sites, and 3.) Z-type, 2-electron acceptors that bind chalcogenide sites. Each of these ligand classes is explored in detail to better understand the surface chemistry of metal chalcogenide nanocrystals.
    [Show full text]