After receiving his BS degree in engineering physics from Tsinghua University at Beijing, China in 1999, Dr. Ji went on to earn a MS in the area of nuclear technology and its application from the same institution in 2002. He then came to the U.S. to enter the Ph.D. program in Nuclear Engineering at the University of Michigan, earning his MS in 2004 and Ph.D. in 2007. During this period, Dr. Ji had participated in several DOE funded projects on the research, development and demonstration of Very-high Temperature Gas-cooled Reactors, one of the promising candidates for Gen IV designs. He had been a research specialist at General Atomics and Argonne National Laboratory in 2005, working on the advanced fuel cycle designs using deep-burn gas cooled reactors.
Wetzel was a Visiting Scientist at Lawrence Berkeley National Laboratory through 1996. In 1997 he joined the High Tech Research Center at Meijo University Nagoya, Japan. In October 2000 he joined Uniroyal Optoelectronics as a Senior Epi Scientist and Green Project Manager. He was responsible for new MOCVD epi processes and developed a production process for high brightness green GaInN/GaN LEDs.
Since March 2004 he is a Future Chips Constellation Professor and Associate Professor of Physics at Rensselaer. The Constellation comprises three chaired faculty who develop new concepts for light emitting devices and optoelectronics. Dr. Wetzel's work has been published in some 110 papers that received over 1500 citations.
Research Interests
Dr. Wetzel’s research centers on the electronic band and defect structure of wide band gap semiconductor materials and devices by means of optical spectroscopy under external perturbation. Since 1993, Dr. Wetzel has focused on group-III nitrides with major contributions in the identification of the residual donor in GaN as oxygen and its DX-type behavior. In the group of Prof. Akasaki, he studied the processes of light emission in GaInN quantum wells. He demonstrated the dominance of piezoelectric polarization in the band structure and the light emission processes. At RPI he implements the concepts of piezoelectric bandstructure control to realize new concepts of high efficiency light emitting devices and solar cells. Current emphasis lies on high brightness light emitting diodes emitting in the 520 – 560 nm green spectral region.
1993 Dr. rer. nat. (Ph.D.), summa cum laude, Physics, Technical University Munich, Munich, Germany.
1988 Diplom (M.S.) Technical Physics, Technical University Munich, Germany.
Specialization in Electronic Devices and Control Theory.
1984 Vordiplom (B.S.) Technical Physics, Technical University Munich, Munich, Germany.
“Determination of Piezoelectric Fields in GaInN Strained Quantum Wells Using the Quantum-Confined Stark Effect,” T. Takeuchi, C. Wetzel, S. Yamaguchi, H. Sakai, H. Amano, I. Akasaki, Y. Kaneko, S. Nakagawa, Y. Yamaoka, and N. Yamada; Appl. Phys. Lett. 73(12), 1691-3 (1998), doi:10.1063/1.122247.
“On p-Type Doping in GaN - Acceptor Binding Energies,” S. Fischer, C. Wetzel, E.E. Haller, B.K. Meyer; Appl. Phys. Lett. 67, 1298-300 (1995), doi:10.1063/1.114403.
“Optical Band Gap in Ga1-xInxN (0