PROFESSIONAL PREPARATION
• Peking University, Beijing, P. R. China, B. S. in Electronics,July 1997.
• Peking University, Beijing, P. R. China, M. S. in Electronics, July 2000.
• Arizona State University, Tempe, Arizona, Ph.D. in Electrical Engineering, November 2005.
• Arizona State University, Tempe, Arizona, Postdoctoral Research Associate, December 2005-Janauary 2007.
 
APPOINTMENTS
February 1, 2007 – present: Assistant Research Professor, Arizona State University, Center for Nanophotonics, Arizona Institute of Nano-Electronics, Tempe, AZ.
December 16, 2005 - January 31, 2007: Postdoctoral Research Associate, Arizona State University, Center for Solid State Electronics Research, Tempe, AZ.
August 2000 - December 15, 2005: Graduate Research Associate, Arizona State University, Center for Solid State Electronics Research, Tempe, AZ.
 
RESEARCH INTEREST
Semiconductor optoelectronic device modeling, fabrication and characterization
Semiconductor optical refrigeration
Si based laser using SiGeSn
Multi-junction solar cell
Novel scanning technology for nanophotonics
 
RESEARCH EXPERIENCES
• Theoretical investigation of the fundamental mechanisms in semiconductor electroluminescence refrigeration; design and fabrication devices; development of novel characterization techniques for optical refrigeration devices.
• Independently designed and constructed unique time resolved luminescence spectroscopy measurement system (1 ns time resolution, 400 nm to 25 µm wavelength range, 10 to 400 K tem-perature range, electroluminescence and photoluminescence capability, user friendly).
• Demonstration of first RT CW GaAsSb/GaAs edge-emitting laser; development of high perform-ance VCSELs and RCLEDs; material and device characterization, device modeling, and design optimization, improve device performance to meet industry standards.
 
PUBLICATION LIST
12 S.-Q. Yu, D. Ding, J.-B. Wang, N. Samal, S. R. Johnson, Y.-H. Zhang, High performance GaAsSb/GaAs quantum well lasers, J. Vac. Sci. Technol. B (Submitted April 2007).
11 S.-Q. Yu, J.-B. Wang, S. R. Johnson, D. Ding, D. Vasileska, Y.-H. Zhang, Impact of electronic density of states on electroluminescence refrigeration, Solid State Electronics (Submitted March 2007).
10 J.-B. Wang, D. Ding, S. R. Johnson, S.-Q. Yu, and Y.-H. Zhang, Determination and improvement of spontaneous emission quan-tum efficiency in GaAs/AlGaAs heterostructures grown by mo-lecular beam epitaxy, Phys. stat. sol. (a) (Submitted November 2006).
9 S. R. Johnson, D. Ding, J.-B. Wang, S.-Q. Yu, and Y.-H. Zhang, Excitation Dependent Photolumines-cence Measurements of the Nonradiative Lifetime and Quantum Efficiency in GaAs, J. Vac. Sci. Technol. B (Accepted).
8 D. Ding, S. R. Johnson, J.-B. Wang, S.-Q. Yu, Y.-H. Zhang, Intrinsic Irreversibility in Semiconductor Light Emission, Phys. stat. sol. (c) 4, No. 5, 1698–1701 (2007).
7 K. Hild, S. Wright, D. Lock, S. Jin, I. Marko, S. Sweeney, S. R. Johnson, S. Chaparro, S.-Q. Yu, and Y.-H. Zhang, Carrier recombination in 1.3µm GaAsSb/GaAs Quantum Well Lasers, Appl. Phys. Lett. 89, 173509 (2006).
6 J.-B. Wang, S. R. Johnson, D. Ding, S.-Q. Yu, Y.-H. Zhang, Influence of photon recycling on cooling efficiency and cooling power in semiconductor luminescence refrigeration, J. Appl. Phys. 100, 043502 (2006).
5 S.-Q. Yu, X. Jin, S. R. Johnson, Y.-H. Zhang, Gain Saturation and Carrier Distribution Effects in Mo-lecular Beam Epitaxy Grown GaAsSb/GaAs Quantum Well Lasers, J. Vac. Sci. Technol. B 24, 1617 (2006).
4 N. Samal, S. R. Johnson, D. Ding, A. K. Samal, S.-Q. Yu, Y.-H. Zhang, High-Power Single-Mode Ver-tical-Cavity Surface-Emitting Lasers, Appl. Phys. Lett. 87, pp161108-1, (2005).
3 S. R. Johnson, C.-Z. Guo, S. A. Chaparro, Yu. G. Sadofyev, J.-B. Wang, Y. Cao, N. Samal, X. Jin, S.-Q. Yu, D. Ding, Y.-H. Zhang, GaAsSb/GaAs Band Alignment Evaluation for Long-Wave Photonic Ap-plications, J. Crystal Growth 251, 521 (2003).
2 D.-S. Jiang, J.-B. Wang, X.-G. Liang, Z.-B. Chen, S.-Q. Yu, Y. Cao, Y.-H. Zhang, C. Navarro, S. Chaparro, S. R. Johnson, LUMINESCENCE PROPERTIES OF GaAsSb/GaAs QUANTUM WELL LA-SER STRUCTURES, JOURNAL OF INFRARED AND MILLIMETER WAVES, Vol.21 No.z1 P.7-10 (2002).
1 S. R. Johnson, S. Chaparro, J.-B. Wang, N. Samal, Y. Cao, Z.-B. Chen, C. Navarro, X. Jin, S.-Q. Yu, D. J. Smith, C.-Z. Guo, P. Dowd, W. Braun, Y.-H. Zhang, GaAs-Substrate Based Long-Wave Active Materials with Type-II Band Alignments, J. Vac. Sci. Technol. B 19, 1501 (2001).
 
SCIENTIFIC HONORS
Palais Outstanding Doctoral Student Award, ASU Electrical Engineering Department. Selected out of 41 Ph.D students that graduated in 2005.