ACCGE 2015 Abstracts Ebook
Total Page:16
File Type:pdf, Size:1020Kb
Table of Contents Introduction/Plenary Correlated Electron Crystals 1 Detector Materials: Scintillators and Semiconductors (ACCGE) 1 Fundamentals of Crystal Growth (ACCGE) 1 III-V Nitride, SiC, and Other Wide Bandgap Materials (Joint ACCGE/OMVPE) 1 Second Symposium on 2D Electronic Materials (Joint ACCGE/OMVPE) 1 Correlated Electron Crystals 2 Detector Materials: Scintillators and Semiconductors (ACCGE) 2 Fundamentals of Crystal Growth (ACCGE) 2 III-V Nitride, SiC, and Other Wide Bandgap Materials (Joint ACCGE/OMVPE) 2 Second Symposium on 2D Electronic Materials (Joint ACCGE/OMVPE) 2 Detector Materials: Scintillators and Semiconductors (ACCGE) 3 Fundamentals of Crystal Growth (ACCGE) 3 III-V Nitride, SiC, and Other Wide Bandgap Materials (Joint ACCGE/OMVPE) 3 Second Symposium on 2D Electronic Materials (Joint ACCGE/OMVPE) 3 Poster Session 1 III-Vs on Silicon (Joint ACCGE/OMVPE) 1 Young Author and AACG Awards Detector Materials: Scintillators and Semiconductors (ACCGE) 4 Fundamentals of Crystal Growth (ACCGE) 4 III-Vs on Silicon (Joint ACCGE/OMVPE) 2 Second Symposium on 2D Electronic Materials (Joint ACCGE/OMVPE) 4 III-V Nitride, SiC, and Other Wide Bandgap Materials (Joint ACCGE/OMVPE) 4 Nonlinear Optical and Laser Host Materials (ACCGE) 1 Thin Film Growth, Epitaxy, and Superlattices (Joint ACCGE/OMVPE) 1 Second Symposium on 2D Electronic Materials (Joint ACCGE/OMVPE) 5 III-V Nitride, SiC, and Other Wide Bandgap Materials (Joint ACCGE/OMVPE) 5 Materials for Photovoltaics and Energy Technology (Joint ACCGE/OMVPE) 1 Nonlinear Optical and Laser Host Materials (ACCGE) 2 Thin Film Growth, Epitaxy, and Superlattices (Joint ACCGE/OMVPE) 2 Second Symposium on 2D Electronic Materials (Joint ACCGE/OMVPE) 6 Poster Session 2 Materials for Photovoltaics and Energy Technology (Joint ACCGE/OMVPE) 2 Materials for Photovoltaics and Energy Technology (Joint ACCGE/OMVPE) 3 Nonlinear Optical and Laser Host Materials (ACCGE) 3 Second Symposium on 2D Electronic Materials (Joint ACCGE/OMVPE) 7 Thin Film Growth, Epitaxy, and Superlattices (Joint ACCGE/OMVPE) 3 Nonlinear Optical and Laser Host Materials (ACCGE) 4 Thin Film Growth, Epitaxy, and Superlattices (Joint ACCGE/OMVPE) 4 Materials for Photovoltaics and Energy Technology (Joint ACCGE/OMVPE) 4 Bulk Crystal Growth 1 Industrial Crystal Growth Technologies and Equipment (ACCGE) 1 Biological, Biomimetic, and Organic Crystallization (ACCGE) 1 OMVPE of Compound Semiconductors for Optoelectronics 1 OMVPE of Compound Semiconductors for Optoelectronics 2 Bulk Crystal Growth 2 Industrial Crystal Growth Technologies and Equipment (ACCGE) 2 Biological, Biomimetic, and Organic Crystallization (ACCGE) 2 Bulk Crystal Growth 3 Industrial Crystal Growth Technologies and Equipment (ACCGE) 3 Novel OMVPE Techniques and In-Situ Monitoring Biological, Biomimetic, and Organic Crystallization (ACCGE) 3 Bulk Crystal Growth 4 Industrial Crystal Growth Technologies and Equipment (ACCGE) 4 Nanocrystals, Quantum Dots and Nanowires (Joint ACCGE/OMVPE) 1 Biological, Biomimetic, and Organic Crystallization (ACCGE) 4 Bulk Crystal Growth 5 Industrial Crystal Growth Technologies and Equipment (ACCGE) 5 Nanocrystals, Quantum Dots and Nanowires (Joint ACCGE/OMVPE) 2 Biological, Biomimetic, and Organic Crystallization (ACCGE) 5 Bulk Crystal Growth 6 Nanocrystals, Quantum Dots and Nanowires (Joint ACCGE/OMVPE) 3 Biological, Biomimetic, and Organic Crystallization (ACCGE) 6 Monday, August 3, 2015 8:00 AM - 10:00 AM Introduction/Plenary Location: Missouri Session Chair(s): Joan Redwing, Luke Mawst 8:30 AM - 9:15 AM GIANT CRYSTALS OF NAICA: THE SCIENCE BEHIND THE BEAUTY Invited Juan M. Garcia-Ruiz Consejo Superior de Investigaciones Cientificas, Armilla (Granada), Spain GIANT CRYSTALS OF NAICA: THE SCIENCE BEHIND THE BEAUTY Juan Manuel García-Ruiz Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Granada, Spain Crystals are everywhere in our day life, but only in a very few cases do they reveal themselves as the large polyhedra that have fascinated mankind since remote times. Even rarer is to find colossal crystals other than those dreamed up in literature and comic masterpieces. However, there are exceptions. The Cave of Giant Crystals in the Naica mine (Mexico) is one of the most amazing displays of mineral beauty ever created by nature. In addition to the colossal columnar crystals of gypsum (CaSO4 2H2O), which in some cases exceed eleven meters in length and one meter in thickness, the scenery developed by the crystalline beams of moonlight luster going through the darkness of the cave, from the floor to the ceiling, is a unique example of harmony based on crystal symmetry. At the same time, deciphering the formation mechanism of these crystals is a fascinating challenge. In this lecture I will review the nucleation and growth of gypsum crystals as the scientific basis for the formation of this remarkable phenomenon of mineralization. References: [1] García-Ruiz JM, Ayora C, Canals A, Otálora F, Geology 35 (2007) 327. [2] Van Driessche A, García-Ruiz JM, Tsukamoto K, Patiño LD, Satoh H, PNAS 108 (2011) 1572 [3] Otálora F & Garcia-Ruiz JM, Chem. Soc. Rev 43 (2014) 2013. 9:15 AM - 10:00 AM AlGaN-BASED TECHNOLOGY: STATE-OF-THE-ART AND REMAINING CHALLENGES Invited Zlatko Sitar North Carolina State University, Raleigh, NC AlGaN alloys are the building blocks of deep UV optoelectronics and high-power devices. It has been demonstrated that the highest crystalline quality AlGaN films with high Al content are obtained on AlN single crystal substrates. Recently, UV LEDs emitting at 265 nm with output powers exceeding 80 mW and high reliability, as well as low-threshold, optically pumped lasers emitting at wavelengths between 230-280 nm have been demonstrated. These results demonstrate the advantages of using AlN substrates for this technology. Despite the encouraging results, challenges in strain management and management of point defects pose the remaining limitations of this technology. Pseudomorphic AlGaN films with dislocation densities lower than 1E3 cm-2 have been achieved, sustaining compressive stresses with thicknesses exceeding 3 µm. If relaxation is not essential for a given application, relaxation schemes can be avoided altogether in favor of pseudomorphic AlGaN films on AlN. As single-crystal AlN substrates have low dislocation densities, of the order of 1E3 cm-2, it is unrealistic to expect sufficient strain accommodation through dislocation bending of pre-existing dislocations. This makes misfit dislocation nucleation an essential mechanism in the relaxation of these films. Composition and strain relaxation in high Al content AlGaN layers grown by MOCVD on AlN substrates will be discussed with respect to the substrate miscut. It was found that the nucleation of misfit dislocations in AlGaN layers depends on the presence of either macrosteps or bilayer steps on the growth surface. As miscut controls the surface step morphology, it plays a crucial role in misfit dislocation nucleation and alloy critical thickness. Following these results, dislocation densities below 105 cm-2 have been obtained in these films for Al content higher than 60%. These low dislocation densities allowed for a systematic approach to the identification and control of compensating point defects that affect n-type conductivity. This approach has been guided by a first-principles-based database that combines point defect data to predict defect concentrations and significant optical transitions for defect identification. This is currently guiding the development of the Fermi level control scheme for point defect management that has allowed for the achievement of high free carrier concentrations in high Al content AlGaN films. The talk will discuss MOCVD processes for control of AlGaN composition and heteroepitaxy, approaches to control strain, point defects, and doping in this material, and implications of this technology for further development of UV optoelectronic and electronic devices. Monday, August 3, 2015 10:30 AM - 12:00 PM Correlated Electron Crystals 1 Location: Lake/Canyon Session Chair(s): Athena Safa-Sefat, John E. Greedan 10:30 AM - 11:00 AM SYNTHESIS, CRYSTAL GROWTH, AND STRUCTURAL CHARACTERIZATION OF NOVEL ZINTL PHASES OF AS, SB AND BI WITH THE D-METALS Invited Svilen Bobev University of Delaware, Newark, DE The crystal chemistry of the intermetallic compounds containing metals with different electronegativities presents a combination of diverse and complicated bonding patterns and unique metal-metal interactions. As part of an ongoing effort to better understand the structure-property relationships in such intermetallics containing d- and/or f-elements, we focused our attention on the ternary systems A-M-As, A-M-Sb and A-M-Bi (A = alkali, alkaline-earth metals, and/or rare-earth metal; M = Mn, Zn, Cd). Recent experimental work carried out by our group led to the discovery of several new classes of transition metal based compounds. Common threads in the structures of all of these are the M-centered tetrahedra of As, Sb or Bi, respectively, which are interconnected through shared corners or edges to form chains, ribbons, or layers with complex topologies. These systems present a case where a strikingly delicate balance between the packing efficiency (size effects) and the valence electron concentration (electronic effects) governs the stability of a particular arrangement over another. The structural relationship between these and some well-known structures with two-dimensional