Wolfgang J. Choyke

  • Research Professor Emeritus
202 Allen Hall
choyke@pitt.edu

Research

We are primarily interested in the optical and electronic characterization of currently important large bandgap semiconductors such as AIN, GaN and SiC. Great emphasis in our research is placed on a close collaboration with the world`s most outstanding growers of single crystal boule material or single crystal epitaxial films. We have also started to learn how to prepare and study single crystal porous SiC. Many new morphologies have been discovered in both n and p type SiC and applications to medicine, gas sensing and fuel cells are being explored. Our current studies involve high resolution optical spectroscopy of free exciton and electronic band structure near the fundamental gap in 4H SiC. 

Selected Publications

  • "Determination of the phonon dispersion of zinc blende (3C) silicon carbide by inelastic x-ray scattering," J. Serrano, J.Strempfer, M. Cardona, M. Schwoerer-Böhning, H. Requardt, M. Lorenzen. B. Stojetz, P. Pavaone and W.J.Choyke, Appl. Phys. Lett. V80, 4360, (2002).
  • "Determination of the electric field in 4H/3C/4H quantum wells due to spontaneous polarization in the 4H SiC matrix," S.Bai, R.P.Devaty, W.J.Choyke, U. Kaiser, G. Wagner, and M.F. MacMillan, Appl. Phys. Lett. V83, 3171, (2003).
  • "Identification of the Carbon Dangling Bond Center at the 4H/-SiC/SiO2 Interface by an EPR Study in Oxidized Porous SiC," J.L. Cantin, H.J. von Bardeleben, Y. Shishkin, Y.Ke, R.P. Devaty and W.J.Choyke, Phys. Rev. Lett. V92, 015502-1, (2004).
  • "Photoelectrochemical etching of n-type 4H Silicon Carbide," Y. Shishkin, W.J.Choyke and R.P.Devaty, Jour. Appl. Phys. V96, 3311, (2004).
  • "SiC pore surface: Surface Studies of 4H-SiC(1-102) and 4H-SiC (-110-2)," U.Starke, W.Y. Lee, C. Coletti, S.E. Saddow, R.P. Devaty and W.J. Choyke. Appl. Phys. Lett. V88, 031915, (2006).
  • "New Evidence for the Second Conduction Band in 4H SiC" W.Klahold, C.Tabachnick, G. Freedman, R.P. Devaty and W.J. Choyke, Materials Science Forum, Vol 897, pp 250-253, (2017).
  • "Silicon Carbide: Presolar SiC Stardust Grains and the Human History of SiC from 1824 to1974" published in the Handbook of Silicon Carbide Materials and Devices, pages 3 to 28,Edited by Zhe Chuan Feng, CRC Press (2023).