Dr. Devaty's research focuses on the large bandgap semiconductors SiC, AlN, GaN and their alloys, heterostructures and superlattices. His interests include infrared reflectance, low temperature photoluminescence, magneto–optical spectroscopy, SiC Schottky barriers, carrier lifetime measurements, and shallow impurities and deep centers in SiC. In recent years porous SiC has been a topic of special interest. Potential applications include biosensors, bone tissue engineering, fuel cells, and substrates for defect reduction in epitaxial films. The group also participates in collaborations to investigate the oxide/SiC interface based on the large interfacial area of porous SiC and the propagation of bulk and surface acoustic waves in porous SiC.
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.
"Field effect in epitaxial graphene on a silicon carbide substrate," Gu, G., Nie, S., Feenstra, R.M., Devaty, R.P., Choyke, W.J., Chan, W.K., Kane, M.G, Applied Physics Letter, 90, 253507 (2007)
"Penetration depths in the ultraviolet for 4H, 6H and 3C silicon carbide at seven common laser pumping wavelengths," Sridhara, S.G., Eperjesi, T.J., Devaty, R.P., Choyke, W.J., Materials Science and Engineering B 61-62 (1999)
"Optical characterization of silicon carbide polytypes," Devaty, R.P., Choyke, W.J., Physica Status Solidi (A) Applied Research, 162, 5 (1997)
"Absorption coefficient of 4H silicon carbide from 3900 to 3250 Å," S. G. Sridhara, R. P. Devaty, and W. J. Choyke, Journal of Applied Physics 84, 2963 (1998)
"Photoluminescence and transport studies of boron in 4H SiC," Sridhara, S.G., Clemen, L.L., Devaty, R.P., Choyke, W.J., Larkin, D.J., King, H.S., Troffer, T., Pensl, G., Journal of Applied Physics 83, no. 12 (1998)
"Newly resolved phonon-assisted transitions and fine structure in the low temperature wavelength modulated absorption and photoluminescence spectra of 6H SiC," Klahold, W.M., Choyke, W.J., Devaty, R.P. (2019) Materials Science Forum, 963 MSF, pp. 341-345.
"High resolution optical spectroscopy of free exciton and electronic band structure near the fundamental gap in 4H SiC." Klahold, W.M., Choyke, W.J., Devaty, R.P. Materials Science Forum 924 MSF, pp. 239-244. (2018)
"New evidence for the second conduction band in 4H SiC," Walter Klahold, Charles Tabachnick, Gabriel Freedman, Robert P. Devaty , Wolfgang J. Choyke, Materials Science Forum, 897, 250 (2017)
"Annealing of electron irradiated, thick, ultrapure 4H SiC between 1100°c and 1500°c and measurements of lifetime and photoluminescence,"
Walter M. Klahold, Robert P. Devaty, Wolfgang J. Choyke , Koutarou Kawahara, Tsunenobu Kimoto, Takeshi Ohshima, Materials Science Forum, 778, 273 (2014)
Biocompatible Sol-Gel Based Nanostructured Hydroxyapatite Coatings on Nano-porous SiC (Book Chapter) Datta, M.K., Sipe, D.M., Ke, Y., (...), Campbell, P.G., Kumta, P.N. Silicon Carbide Biotechnology pp. 333-349