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Department of Physics, Applied Physics, and Astronomy
Rensselaer Polytechnic Institute
110 Eighth Street, Troy, New York 12180-3590 USA

Telephone:
(518) 276-6310
Fax: (518) 276-6680
E-mail: physics@rpi.edu

Wellfleet Career Development Constellation Professor, Future Chips; Associate Professor of Physics

Education:
Ph.D. (Dr. rer. nat.), Physics, Technical University Munich, 1993.

Career Highlights:
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:
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, 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.

Selected Publications:
Wavelength-Resolved Low-Frequency Noise of GaInN/GaN Green Light Emitting Diodes; S.L. Rumyantsev; C. Wetzel, M.S. Shur; J. Appl. Phys. 100, 084506, (2006). http://dx.doi.org/DOI:10.1063/1.2358409

Very High Quality AlN Grown on (0001) Sapphire by Metal-Organic Vapor Phase Epitaxy; Y.A. Xi, K.X. Chen, F. Mont, J.K. Kim, C. Wetzel, E.F. Schubert, W. Liu, X. Li, J.A. Smart; Appl. Phys. Lett 89, 103106, (2006). http://dx.doi.org/doi:10.1063/1.2345256

Time Resolved Charge Profiling of Polarization Dipoles in High Power 525 nm Green GaInN/GaN Light Emitting Structures, Y. Xia, Y. Li, Y. Ou, W. Zhao, M. Zhu, I. Yilmaz, T. Detchprohm, E.F. Schubert, and C. Wetzel; Phys. Stat. Sol. (a) 203(7), 1806–1810 (2006). http://dx.doi.org/doi:10.1002/pssa.200565284

Development of High Power Green Light Emitting Diode Chips; C. Wetzel and T. Detchprohm; MRS Internet J. Nitride Semicond. Res. 10, 2 (2005). http://nsr.mij.mrs.org/10/2/

Optimization of Green and Deep Green GaInN/GaN Light Emitting Diodes; C. Wetzel, P. Li, T. Detchprohm, and J.S. Nelson; Phys. Stat. Sol. (c), 2(7) 2871-3 (2005). http://dx.doi.org/doi:10.1002/pssc.200461391

GaInN/GaN Growth Optimization for High-Power Green Light-Emitting Diodes; C. Wetzel, T. Salagaj, T. Detchprohm, P. Li, J.S. Nelson, Appl. Phys. Lett. 85(6), 866 - 8 (2004). http://dx.doi.org/10.1063/1.1779960

Anomalous Features in the Optical Properties of Al_1-xIn_xN on GaN Grown by Metal Organic Vapor Phase Epitaxy; S. Yamaguchi, M. Kariya, S. Nitta, T. Takeuchi, C. Wetzel, H. Amano, I. Akasaki; Appl. Phys. Lett. 76(7), 876 - 8 (2000). http://dx.doi.org/10.1063/1.125615

Electric-Field Strength, Polarization Dipole, and Multi-Interface Band Offset in Piezoelectric Ga_1-xIn_xN/GaN Quantum-Well Structures; C. Wetzel, T. Takeuchi, H. Amano, I. Akasaki; Phys. Rev. B, Condens. Matter 61(3), 2159 - 63 (2000). http://dx.doi.org/10.1103/PhysRevB.61.2159

Quantized States in Ga_1-xIn_xN/GaN Heterostructures and the Model of Polarized Homogeneous Quantum Wells; C. Wetzel, T. Takeuchi, H. Amano, I. Akasaki; Phys. Rev. B, Condens. Matter 62(20), 13302 - 5 (2000). http://dx.doi.org/10.1103/PhysRevB.62.R13302

Optical Band Gap in Ga_1-xIn_xN(0 < x < 0.2) on GaN by Photoreflection Spectroscopy; C. Wetzel, T. Takeuchi, S. Yamaguchi, H. Katoh, H. Amano, I. Akasaki; Appl. Phys. Lett. 73(14), 1994 - 6 (1998). http://dx.doi.org/10.1063/1.122346

Pressure Induced Deep Gap State of Oxygen in GaN; C. Wetzel, T. Suski, J.W. Ager III; E.R. Weber, E.E. Haller, S. Fischer, B.K. Meyer, R.J. Molnar, P. Perlin, Phys. Rev. Lett. 78(20), 3923 - 6 (1997). http://dx.doi.org/10.1103/PhysRevLett.78.3923

Contact:
(518) 276-3755
wetzel@rpi.edu

Home Page: http://www.rpi.edu/~wetzel/