Wolfgang Choyke

Department of Physics and Astronomy, University of Pittsburgh
Ph.D., Ohio State University, 1952

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. Most recently we have 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.

We study optical and electrical properties by a variety of techniques, and also put considerable effort into preparation of specialized samples. Regarding nanoscience and technology, examples of relevant work include the fabrication and investigation of porous SiC and investigations of polytype inclusions which behave as quantum wells.

We are also investigating SiC as a tool for nano-machining applications, as a substitute for diamond, towards applications for which diamond does not work well or at all.

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.ChoykePhys. 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)

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