John C. Angus

Professor of Engineering
Chemical Engineering
Case Western Reserve University
United States of America

Biography

Education: B.S. Chemical Engineering, University of Michigan, 1956 M.S. Chemical Engineering, University of Michigan, 1958 Ph. D. Chemical Engineering, University of Michigan, 1961 Sc. D. Chemical Engineering, Ohio University, 1998

Research Intrest

In the 1960’s Professor Angus and Professor Nelson Gardner published studies of chemical vapor deposition (CVD) of diamond. Since that early work, this field has gone from an object of scorn, to a curiosity, to a significant industrial process practiced throughout the world. Growth rates have increased from the minuscule to where several carat single crystals can be grown in reasonable times. Diamond CVD is an enabling technology that permits the exploitation of diamond's exceptional properties outside its traditional role in cutting and grinding. For example, CVD diamond is used for instrument windows for high power microwave, infrared and ultraviolet devices, for wide area and integrated heat management systems, for radiation detectors (including in the Large Hadron Collider at CERN), and in diamond electrodes for use in aggressive environments and in electrochemical-based detectors. In addition to diamond, Professor Angus and Professor Kathleen Kash have studied novel methods for synthesis of gallium nitride and indium nitride. Professor Heidi Martin, Professor Uziel Landau and Professor Angus performed some of the earliest studies of conducting diamond for electrochemical electrodes. This work was the first to show the very wide potential window for diamond, which enables numerous applications. Professor Vidhya Chakrapani, Professor Angus and colleagues have recently investigated charge transfer between diamond and adsorbed water films. We have shown that the electron transfer is to the four-electron aqueous, oxygen redox couple. We find that the effect is not restricted to diamond; in humid air it can switch the conductivity of carbon nanotubes and graphene between n-type and p-type, and it modulates the yellow and green luminescence from both gallium nitride and zinc oxide. Currently, Professor Angus, Professor Isaac Greber and undergraduate student, Evan Tsiklidis, are studying charge transfer between objects of identical composition but of different size and surface roughness. A project with undergraduate Olivia Dahm involves study of the initial stages of diamond nucleation and means of growing Lonsdaleite, the so-called “hexagonal diamond.”

List of Publications
John C. Angus, “Electrochemistry on Diamond: History and Current Status,” pp. 3-19, in Synthetic Diamond Films: Preparation, Electrochemistry, Characterization and Applications, Enric Brillas and Carlos Alberto Martínez-Huitle (Editors), John Wiley, Hoboken, NJ, 2011
Timothy J. Peshek, John C. Angus, Kathleen Kash, “Experimental Investigation of the Enthalpy, Entropy and Free Energy of Formation of GaN,” J. Cryst. Growth 311, 185-189 (2008).
Vidhya Chakrapani, Chandrasekhar Pendyala, Kathleen Kash, Alfred B. Anderson, Mahendra K. Sunkara, John C. Angus, “Electrochemical Pinning of the Fermi Level: Mediation of Photoluminescence from GaN and ZnO,” J. Am. Chem. Soc. 130, 12944-12952 (2008).
Vidhya Chakrapani, John C. Angus, Alfred B. Anderson, Scott D. Wolter, Brian R. Stoner and Gamini U. Sumanasekera, “Charge Transfer Equilibria Between Diamond and an Aqueous Oxygen Electrochemical Redox Couple,” Science 318, 1424-1430 (2007)