The research in our lab involves studies of materials used in microelectronic, optical, and magnetic applications. In the area of electronics, present and ongoing materials of interest are SiC and GaN. They are studied in order to deduce their potential in high speed and/or high power electronic applications. Specifically, point defects in SiC wafers are examined using electron paramagnetic resonance spectrosocopy (EPR) so that we may understand their role in achieving semi-insulating material. GaN, the semiconductor which will form the basis of future lighting applications, contains several point defects critical to its application in both light emitting diodes and high power devices. We address the chemical kinetics of these defects to assess the response of the material to varying environments.
Recent Journal Publications
J. Dashdorj, M.E. Zvanut and J.G. Harrison, “Measurements of optical cross sections of carbon vacancy in 4H-SiC by time-dependent photo-electron paramagnetic resonance”, J. Appl. Phys. 104, 113707 (2008).
M.E. Zvanut, S. Jeddy, and E. Towett, G.M. Janowski, C. Brooks and D. Schlom, “An annealing study of an oxygen vacancy related defect in SrTiO3 substrates”, J. Appl. Phys. 104, 064122 (2008).
Wonwoo Lee and M. E. Zvanut, “A study of deep defect levels in semi-insulating SiC using optical admittance spectroscopy”, J. Electron. Materials 36, 623 (2007).
W. C. Mitchel, W. D. Mitchell, G. Landis, H. E. Smith, Wonwoo Lee, and M. E. Zvanut, “Vanadium donor and acceptor levels in semi-insulating 4H- and 6H-SiC”, J. Appl. Phys. 101, 013707 (2007)
M.E. Zvanut, Wonwoo Lee, W.C. Mitchel, W.D. Mitchel, W.D. Mitchell, and G. Landis, “The acceptor level for vanadium in 4H and 6H SiC”, Physica B 376-377, 346 (2006).
M.E. Zvanut, Haiyan Wang, Mpumelelo Richards, and V. V. Konovalov, “Observation of a spin one native defect in as-grown high purity semi-insulating 4H SiC”, J. Appl. Phys. 97, 123509 (2005).
D. M. Matlock, M. E. Zvanut, Haiyan Wang, Jeffrey R. DiMaio, R.F. Davis, J.E. Van Nostrand, R. L. Henry, Daniel Koleske and Alma Wickenden, “The effects of oxygen, nitrogen, and hydrogen annealing on Mg acceptors in GaN as monitored by electron paramagnetic resonance spectroscopy”, Journal of Electronic Materials 34, 34 (2005).
Recent Conference Publications
M. E. Zvanut, G. Ngetich, H. J. Chung, A. Y. Polyakov, M. Skowronski, E. Glaser, and N. Garces, “Defect level of the carbon vacancy carbon antisite pair center in SI 4H SiC”, Mat. Sci. Forum 600-603, 385 (2009).
E.R. Glaser, N.Y. Garces, W.E. Carlos, M.E. Zvanut, B. Magnusson, D.M. Hansen, G. Chung, and M.J. Loboda, “Infrared PL Signatures of n-type Bulk SiC Substrates with Nitrogen Impurity Concentration Between 1016 and 1017 cm-3”, Mat. Sci. Forum 600-603, 449 (2009).
J. Dashdorj and M.E. Zvanut, “Study of chromium impurities in SrTiO3 by photo-electron paramagnetic resonance spectroscopy”, edited by J.F. Scott, V. Gopalan, M. Okuyama, and M. Bibes (Mater. Res. Soc. Symp. Proc. Volume 1034E, Warrendale, PA, 2008), 1034-K10-19.
M. E. Zvanut, G. Ngetich, H. J. Chung, A. Y. Polyakov, and M. Skowronski, “A study of vacancies and vacancy pair defects in 4H SiC grown by halide chemical vapor deposition”, J. Mat. Sci: Mat. in Electronics 19, 678 (2008).
M.E. Zvanut and J. van Tol, “Nitrogen-related point defect in 4H and 6H SiC”, Physica B 401-402, 73-76 (2007).
Shehnaz Jeddy, Mary Ellen Zvanut, Brian Einstein Lassiter, Gregg M. Janowski and Leonard J. Brillson “Themal Stability of defects in substrates of multiferroic materials”, in Ferroelectrics and Multiferroics, edited by V. Gopalan, J-P. Maria, M. Fiebig, C-W. Nan (Mater. Res. Soc. Symp. Proc. 966E, Warrendale, PA, 2007), 0966-T05-04.
M. E. Zvanut, H. J. Chung, A. Y. Polyakov, and M. Skowronski, “Point defects in 4H SiC grown by Halide Chemical Vapor Deposition”, Mat. Sci. Forum 556-557, 473 (2007).