Research Interests

My research interests are growth and doping of semiconductor ZnO and ZnO-alloy thin films for use as layers in optoelectronic devices. Our laboratory was the first to synthesize p-type doped ZnO at levels sufficient for device fabrication, with arsenic as dopant. The crystal and band structure characteristics of ZnO are similar to those of GaN; however, the properties of ZnO are thought to be more favorable than those of GaN or other wide bandgap semiconductors for optoelectronic device applications. Applications include LEDs and LDs that span the UV and visible spectral regions, UV detectors with visible and solar blind features, and FETs with ultrahigh frequency capabilities—possibly into the THz range.

“Next Generation of Oxide Photonic Devices: ZnO-Based Ultraviolet Light Emitting Diodes,” Y.R. Ryu et al., Appl. Phys. Lett. 88, 241108 (2006), and ref. therein.

“ZnO-based LEDs begin to show full-color potential,” H.W. White and Y.R. Ryu, Compound Semiconductor 12, No. 7, pp. 16-18 (2006). 

More complete description of research work.

 “Optical and Structural Properties of ZnO Films Deposited on GaAs by Pulsed Laser Deposition,” Y.R. Ryu, S. Zhu, J.D. Budai, H.R. Chandrasekhar, P.F. Miceli, and H.W. White, J. Appl. Phys., 88, 201-4 (2000).

“Comparative Study of Textured and Epitaxial ZnO Films,” Y.R. Ryu, S. Zhu, J.M. Wrobel, H.M. Jeong, P.F. Miceli, and H.W. White, J. Cryst. Growth 216, 326-329 (2000).

“Synthesis of P-Type ZnO Films,” Y.R. Ryu, S. Zhu, D.C. Look, J.M. Wrobel, H.M. Jeong, and H.W. White, J. Cryst. Growth 216, 330-34 (2000).

“Fabrication of Homostructural ZnO P-N Junctions,” Y.R. Ryu, W.J. Kim, and H.W. White, J. Cryst. Growth, 219, 419-22 (2000).

“Properties of Arsenic (As) Doped p-type ZnO grown by Hybrid Beam Deposition,” Y.R. Ryu, T.S. Lee and H.W. White, Appl. Phys. Lett. 83, 87-89 (2003).

“Fabrication of Homostructural ZnO p-n Junctions and Ohmic Contacts to Arsenic-doped p-type ZnO Y.R. Ryu,” T.S. Lee, J.H. Leem and H.W. White, Appl. Phys. Lett. 83, 4032-34 (2003).

“A Technique of Hybrid Beam Deposition for Synthesis of ZnO and Other Metal Oxides”, Y. R. Ryu, T. S. Lee, and H. W. White, J. Crystal Growth 261, 502-07 (2004).

“ZnO Devices: Photodiodes and P-type Field-Effect Transistors,” Y. R. Ryu, J. A. Lubguban, and T. S. Lee, H. W. White, Y. S. Park, C. J. Youn. Appl. Phys. Lett. 87, 153504-06 (2005).

“Wide-Band Gap Oxide Alloy – BeZnO,” Y. R. Ryu, T. S. Lee, J. A. Lubguban, A. Corman, H. W. White, J. H. Leem, M. S. Han, Y.S. Park, C. J. Youn, and W. J. Kim. Appl. Phys. Lett. 88, 052103-04 (2006).

“Next generation of oxide photonic devices: ZnO-based ultraviolet light emitting diodes,” Y. R. Ryu, T.S. Lee, J. A. Lubguban, H. W. White, B.J. Kim, Y. S. Park, and  C. J. Youn, Appl. Phys. Lett. 88(24) 1108 (2006).

“ZnO-based LEDs begin to show full –color potential,” Henry White and Yung Ryu, Compound Semiconductor, (to appear, August 2006).