WELCOME to the Electronic Materials & Devices Lab

The Electronic Materials and Devices Lab (EMDL) formed in 1991 by Professor Steve Ringel when he arrived in the Department of Electrical and Computer Engineering at Ohio State as an assistant professor.  Since then, EMDL has grown to support the graduation of 25 PhD students, 52 MS students, 11 postdoctoral researchers and many undergraduate research students carrying out research supported by U.S. government agencies, industry and the state of Ohio.  EMDL graduates have gone on to become vice presidents of major technology companies, distinguished research scientists at government labs, distinguished faculty at leading universities in the U.S. and overseas, senior engineers, technology entrepreneurs, and even a patent attorney!  EMDL students, staff and faculty are engaged in research collaborations across Ohio, the U.S. and many countries in Europe, Asia and Australia. 
EMDL research sits at the nexus of device engineering, electronic materials, applied physics and chemistry, with focus areas on photovoltaics, electronic devices, power electronics, and optoelectronics. We routinely partner with industry collaborators through a variety of corporate engagements, some of which are intertwined with the OSU Institute for Materials Research (imr.osu.edu) for which Professor Ringel is the current and founding director (since 2006). EMDL students come from a range of academic backgrounds that include electrical engineering, materials science and engineering, physics, chemistry, mechanical engineering and chemical engineering.  Both interdisciplinary research and basic research that has translational impact on technology are strongly encouraged!  A sampling of typical EMDL research projects focus on:
  • III-V compound semiconductor photovoltaics for space and terrestrial applications
  • III-V/Si heteroepitaxial integration, lattice-mismatched heterostructures
  • Defect characterization
  • Epitaxial growth (Molecular beam epitaxy & metalorganic chemical vapor deposition)
  • ultra-wide bandgap gallium oxide materials and devices
  • wide bandgap gallium nitride materials, RF devices and power transistors
  • defects and reliability in UWBG and WBG transistors and CIGS solar cells
  • radiation effects in semiconductor materials and devices
An idea of what EMDL is all about can be found via the various links on this simple website. 
For more information about research opportunities please contact any of the EMDL faculty – Steve Ringel, Tyler Grassman or Aaron Arehart.
Thanks for visiting EMDL!
Steven A. Ringel
Distinguished University Professor
Neal A. Smith Endowed Chair of Electrical Engineering
Associate Vice President for Research, OSU Office of Research
Executive Director, Institute for Materials Research


If you have an update for this page please contact Jennifer Donovan donovan.205@osu.edu

Recent Publications


  • Daniel L Lepkowski, Tal Kasher, Jacob T Boyer, Daniel J Chmielewski, Tyler J Grassman, Steven A Ringel, “The Critical Role of AlInP Window Design in III–V Rear-Emitter Solar Cells,” IEEE Journal of Photovoltaics, pgs. 1-7, (March 2020) https://doi.org/10.1109/JPHOTOV.2020.2978863  
  • H. Ghadi, J. F. McGlone, C. M. Jackson, E. Farzana, Z. Feng, A. F. M. A. U. Bhuiyan, H. Zhao, A. R. Arehart, and S. A. Ringel, “Full bandgap defect state characterization of β-Ga2O3 grown by metal organic chemical vapor deposition,” APL Materials, 8 (2), 021111 (Feb. 2020) https://doi.org/10.1063/1.5142313


  • D.L. Lepkowski, J.T. Boyer, D.J Chmielewski, A.C. Silvaggio, S.A. Ringel and T.J. Grassman, Investigation of Rear-Emitter GaAs0.75P0.25Top Cells for Application to III–V/SiTandem Photovoltaics,“ IEEE Journal of Photovoltaics 9(6), 1644-1651 (NOV 2019) https://doi.org/10.1109/JPHOTOV.2019.2939069 
  • Z. Xia, H. Chandrasekar, W.Moore, C. Wang, A.J. Lee, J. McGlone, N.K. Kalarickal, A. Arehart, S.A. Ringel, F, Yang and S, Rajan, “Metal/BaTiO3/β-Ga2O3 dielectric heterojunction diode with 5.7 MV/cm breakdown field,”Appl. Phys. Lett. 115, 252104, (DEC 2019) https://doi.org/10.1063/1.5130669  
  • E. Farzana, A. Mauzi, J. B. Varley, T. Blue, J. S. Speck, A. R. Arehart, and S. A. Ringel, “Influence of Neutron Irradiation on Deep Levels in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy,” APL Materials 7 (12), 121102 (DEC 2019) https://doi.org/10.1063/1.5126463 
  • N. K. Kalarickal, Z. Xia, J. McGlone, S. Krishnamoorthy, W. Moore, M. Brenner, A. R. Arehart, S. A. Ringel, and S. Rajan, “Mechanism of Si doping in plasma assisted MBE growth of β‑Ga2O3,” Appl. Phys. Lett., 115 (15), 152106 (OCT 2019) https://doi.org/10.1063/1.5123149 
  • J. M. Johnson, Z. Chen, J. B. Varley, C. M. Jackson, E. Farzana, Z. Zhang, A. R. Arehart, H. Huang, A. Genc, S. A. Ringel, C. G. Van de Walle, D. A. Muller, and J. Hwang, “Unusual Formation of Point Defect Complexes in the Ultra-wide Band Gap Semiconductor β-Ga2O3,” Phys. Rev. X, 9 (4), 041027 (NOV 2019) https://doi.org/10.1103/PhysRevX.9.041027 
  • H. Chandrasekar, J. Cheng, T. Wang, Z. Xia, N.G. Combs, C.R Freeze, P.B Marshall, J. McGlone, A. Arehart, S.A. Ringel, A. Janotti, S. Stemmer, W. Lu and S.Rajan, "Velocity saturation in La-doped BaSnO3 thin films,” Appl. Phys. Lett., 115 (15), 092102 (AUG 2019) https://doi.org/10.1063/1.5097791 
  • J. F. McGlone, Z. Xia, C. Joishi, S. Lodha, S. Rajan, S. Ringel, and A. R. Arehart, “Identification of critical buffer traps in Si δ-doped β-Ga2O3 MESFETs,” Appl. Phys. Lett., 115 (15), 153501, (OCT 2019 - Online) https://doi.org/10.1063/1.5118250  
  • C. Joishi, Y. Zhang, Z. Xia, W. Sun, A.R Arehart, S.A. Ringel, S. Lodha and S. Rajan, “Breakdown Characteristics of β -(Al0.22Ga0.78)2O3/Ga2O3 Field-Plated Modulation-Doped Field-Effect Transistors,” IEEE Electron Device Letters 40 (8), 99 (JUNE 2019) https://doi.org/10.1109/LED.2019.2921116 
  • Z. Xia, H. Xue, C. Joishi, J. McGlone, N. K. Kalarickal, S. H. Sohel, M. Brenner, A. Arehart, S. Ringel, S. Lodha, W. Lu, and S. Rajan, “β -Ga2O3 Delta-Doped Field-Effect Transistors With Current Gain Cutoff Frequency of 27 GHz,” IEEE Electron Device Letters, 40 (7), 1052–1055 (JULY 2019) https://doi.org/10.1109/LED.2019.2920366 
  • Y. Zhang, Z. Xia, J. McGlone, W. Sun, C. Joishi, A. R. Arehart, S. A. Ringel, and S. Rajan, “Evaluation of Low-Temperature Saturation Velocity in β‑(AlxGa1–x)2O3/Ga2O3 Modulation-Doped Field-Effect Transistors,” IEEE Transactions on Electron Devices, 66 (3), 1574–1578 (MAR 2019) https://doi.org/10.1109/TED.2018.2889573 
  • D. A. Gleason, K. Galiano, J. L. Brown, A. M. Hilton, S. A. Ringel, A. R. Arehart, E. R. Heller, D. L. Dorsey, and J. P. Pelz, “Local trap spectroscopy on cross-sectioned AlGaN/GaN devices with in situ biasing,” Appl. Phys. Lett., 114, 053510 (FEB 2019) https://doi.org/10.1063/1.5079745 
  • W. Sun, J. Joh, S. Krishnan, S. Pendharkar, C.M Jackson, S.A. Ringel and A.R. Arehart, “Investigation of Trap-induced Threshold Voltage Instability in GaN-on-Si MISHMETs,” IEEE Transactions on Electron Devices 66 (2), 890-895 (JAN 2019) https://doi.org/10.1109/TED.2018.2888840 
  • Esmat Farzana, Max F. Chaiken, Thomas E. Blue, Aaron R. Arehart and Steven A. Ringel, “Impact of deep level defects induced by high energy neutron radiation in -Ga2O3,” APL Materials, 7 (2), 022502 (FEB 2019) https://doi.org/10.1063/1.5054606 

Recent News

Congratulations graduates!

Dr. Wenyuan Sun
Dr. Pran Paul
Dr. Kevin Galiano
Dr. Esmat Farzana
Dr. Daniel Joseph Chmielewski
Dr. Christine M. Jackson

Prof. Steven Ringel elevated to IEEE Fellow

Prof. Steven Ringel was elevated to IEEE Fellow (Institute of Electrical and Electronic Engineers), effective 1 January 2020, with the following citation: For contributions to compound semiconductor phototovoltaics. IEEE Fellow is the highest grade of membership and is recognized by the technical community as a prestigious honor and an important career achievement.

The IEEE is the world’s leading professional association for advancing technology for humanity. Through its 400,000 plus members in 160 countries, the association is a leading authority on a wide variety of areas ranging from aerospace systems, computers and telecommunications to biomedical engineering, electric power and consumer electronics.

The IEEE Grade of Fellow is conferred by the IEEE Board of Directors upon a person with an outstanding record of accomplishments in any of the IEEE fields of interest. The total number selected in any one year cannot exceed 0.1% of the total voting membership. 

Lepkowski Wins Best Poster at 2019 PVSC

Lepkowski wins best poster on June 18 (TUES) at 2019 PVSC in Chicago IL.