Scientists

ZHAOQUAN (Joe) ZENG

Joe

Professional Experience

Zhaoquan is currently a Senior Development Engineer in Electrical and Computer Engineering at UC Davis, supporting the Compound Semiconductor Optoelectronics Laboratory of Prof. Jerry M. Woodall. His major role is to refurbish and operate an old Varian GEN II MBE (bought from UCSB), then develop the true green LED and high efficiency solar cell using GaAsZnSe quaternary alloys.

He got his PhD in Condensed Matter Physics from Institute of Physics, Chinese Academy of Science, advised by Profs. Xiaolong Du and Qikun Xue, in 2007. In his thesis, he developed several surface modification techniques to grow high quality ZnO films through interface engineering by MBE toward the developing of next generation LED prototype device on different substrates, e.g. MgAl2O4, Al2O3, Si, LiNb/TaO3. After that, he joined the center of semiconductor physics in nanostructures (C-SPIN) at University of Arkansas. With the strong support from Prof. Gregory J. Salamo, he reconstructed two MBE systems to grow novel functional oxides and Bi-related quantum materials. His works on integrating of topological insulators on GaAs substrate was highlighted in AIP Advance and selected as one of EDITOR’S PICKS and republished by Phys.Org, ScienceDaily, and EurekAlert!,land in over 20 public medias and news websites. In 2012, he began to work with Prof. Leonard J. Brillson in his Electronic Materials and Nanostructures Lab (EMNL) at Ohio State University. Taking the advantage of a cathodoluminescence spectroscopy (CL) system UHV-connected with a Veeco Gen 930 MBE and PHI 5000 VersaProbeTM XPS/UPS system (MBE/XPS/UPS/CL), he grew BaTiO3/SrTiO3 heterojunctions and monitored its band offset and interface dipole formation in-situ as they formed, monolayer by monolayer a first technical feat. Further, he successfully grew one micron-thick bulk Ba0.5Sr0.5TiO3 films on MgO substrates by MBE for the first time and, in collaboration with the Naval Research Laboratory, obtained near state-of-art microwave properties through post-annealing defect reduction guided by DRCLS. In addition, he accomplished a freestanding complex oxide film – BaTiO3, which provides a new research platform for strain engineering novel functional oxides.

His current research interests include in-situ and ex-situ characterization and prototype device fabrication of semiconductors, complex oxides, novel quantum materials grown by MBE, i.e. AFM, XRD, TEM, PL, EL, I-V, XPS/UPS and Cathodoluminescence spectroscopy.

So far, he has published 37 peer-reviewed papers and 15 patents and given 19 talks or posters at international conference. Also, he is an active member of MRS and APS.

Employment History

  • 09/2015-Present, Senior Development Engineer, UCDAVIS
  • 08/2012-08/2015, Postdoctoral Researcher, Ohio State University
  • 01/2011-07/2012, Research Associate, University of Arkansas
  • 09/2007-01/2011, Postdoctoral Fellow, University of Arkansas
  • 09/2002-08/2007, Research Assistant, Institute of Physics, CAS

Degrees

Ph.D. in Condensed Matter Physics (2007), Institute of Physics, CAS

Thesis: Epitaxial Growth of High-quality ZnO Single Crystal Film and Its P-type Doping by MBE

Master in Physics Electronics (2004), Qufu Normal University

Bachelor in Physics (2001), Qufu Normal University

Contact

Office: 3101 Kemper Hall
Email: zqzeng (at) ucdavis.edu

Selected Publications

Peer-reviewed article:

  1. Z. Q. Zeng, Adrian Podpirka, Steven Kirchoefer, T. J. Asel, L. J. Brillson, “Direct correlation and strong reduction of native point defects and microwave dielectric loss in air-annealed (Ba,Sr)TiO3,” Appl. Phys. Lett. 106, 182903 (2015).
  2. M. M. Rutkowski, K. McNicholas, Z. Q. Zeng, F. Tuomisto and L. J. Brillson, “Optical identification of oxygen vacancy formation at SrTiO3–(Ba,Sr)TiO3 heterostructures,” J. Phys. D: Appl. Phys. 47, 255303 (2014).
  3. Snjezana Balaz, Zhaoquan Zeng and Leonard J. Brillson, “Heterojunction Band Offsets and Dipole Formation at BaTiO3/SrTiO3 Interface,” J. Appl. Phys.114, 183701 (2013).
  4. Z. Q. Zeng, T. A. Morgan, D. S. Fan, C. L, Y. Hirono, X. Hu, J. S. Lee, J. Wang, Zh. M. Wang, S. Q. Yu, M. E. Hawkridge, M. Benamara, G. J. Salamo, “Molecular Beam Epitaxial Growth of Bi2Te3 and Sb2Te3 Topological Insulators on GaAs (111) Substrates,” AIP Advances, 3, 072112 (2013). [Highlighted by AIP, and selected as EDITOR’S PICKS]
  5. M. M. Rutkowski, K. M. McNicholas, Z. Q. Zeng, and L. J. Brillson, “Design of a UHV Transfer Mechanism to Interconnect an Oxide MBE Growth Chamber and an XPS Analysis System,” Rev. Sci. Instrum. 84, 065105 (2013).
  6. D. Fan, Z. Q. Zeng, V. G. Dorogan, Y. Hirono, C. Li, Yu. I. Mazur, S.-Q. Yu, S. R. Johnson, Zh. M. Wang and G. J. Salamo, “Bismuth surfactant mediated growth of InAs quantum dots by molecular beam epitaxy,” J. Mater. Sci: Mater. Eletron. 24, 1635 (2013).
  7. J. Wu, G. Chen, Z. Q. Zeng, S. B. Li, X. L. Wu, Zh. M. Wang, G. J. Salamo, “Ordered SrTiO3 Nanoripples Induced by Focused Ion Beam,” Nano-Micro Lett. Vol 4, pp 243-246 (2012).
  8. D. Fan, Z. Q. Zeng, X. Hu, V. G. Dorogan, C. Li, M. Benamara, M. E. Hawkridge, Yu, I. Mazur, S.-Q. Yu, S. R. Johnson, Zh. M. Wang, and G. J. Salamo, “Molecular Beam Epitaxy Growth of GaAsBi/GaAs/AlGaAs Separate Confinement Heterostructures,” Appl. Phys. Lett. 101, 181103 (2012).
  9. C. Li, Z. Q. Zeng, D. S. Fan, Y. Hirono, J. Wu, T. A. Morgan, X. Hu, S. Q. Yu, Zh. M.Wang, G. J. Salamo, “Bismuth Nano-droplets for Group-V Based Molecular-Beam Droplet Epitaxy,” Appl. Phys. Lett. 99, 243113 (2011).
  10. H. Zheng, Z. X. Mei, Z. Q. Zeng, Y. Z. Liu, L. W. Guo, J. F. Jia, Q. K. Xue, Z. Zhang, X. L. Du, “Fabrication and characterization of high quality n-ZnO/p-GaN heterojunction light emission diodes,” Thin Solid Films 520, 445 (2011).
  11. J. Wu, Zh. M. Wang, A. Z. Li, Z. Q. Zeng, S. B. Li, G. Chen, G. J. Salamo, “Formation of GaAs Double Rings Through Gallium Migration and Nanodrilling,” Journal of nanoelectronics and optoelectrics 6,58 (2011).
  12. Z. Q. Zeng, Y. Z. Liu, H. T. Yuan, Z. X. Mei, X. L. Du, J. F. Jia, Q. K. Xue, Z. Zhang, G. J. Salamo, ”Controlled growth of Zn-polar ZnO film on MgAl2O4 (111) substrate using MgO buffer layer,” J. Phys. D: Appl. Phys. 43, 085301 (2010).
  13. X. N. Wang, Y. Wang, Z. X. Mei, J. Dong, Z. Q. Zeng, H. T. Yuan, T. C. Zhang, X. L. Du, J. F. Jia and Q. K. Xue, X. N. Zhang, Z. Zhang, Z. F. Li, W. Lu, “Interface engineering for high-quality epitaxy of ZnO film on Si(111),” Appl. Phys. Lett.90, 151912 (2007).
  14. Z. Q. Zeng, Y. Z. Liu, H. T. Yuan, Z. X. Mei, X. L. Du, J. F. Jia, Q. K. Xue, Z. Zhang, “Surface modification of MgAl2O4 (111) for growth of high-quality ZnO epitaxial films,” Appl. Phys. Lett. 90, 081911 (2007).
  15. Y. Wang, X. L. Du, Z. X. Mei, Z. Q. Zeng, M. J. Ying, H. T. Yuan, J. F. Jia, Q. K. Xue, Z. Zhang, “Cubic nitridation layers on sapphire substrate and their role in polarity selection of ZnO films,” Appl. Phys. Lett. 87, 051901 (2005).
  16. M. J. Ying, X. L. Du, Y. Z. Liu, Z. T. Zhou, Z. Q. Zeng, Z. X. Mei, J. F. Jia, H. Chen, Q. K. Xue, Z. Zhang, ”Interface engineering for lattice-matched epitaxy of ZnO on (La,Sr)(Al,Ta)O3 (111) substrate,” Appl. Phys. Lett. 87, 202107 (2005)
  17. Z. X. Mei, X. L. Du, Y. Wang, M. J. Ying, Z. Q. Zeng, H. Zheng, J. F. Jia, Q. K. Xue, Z. Zhang, “Controlled growth of Zn-polar ZnO epitaxial film by nitridation of sapphire substrate,” Appl. Phys. Lett. 86, 112111 (2005).
  18. H. P. Sun, X. Q. Pan, X. L. Du, Z. X. Mei, Z. Q. Zeng, Q. K. Xue, “Defects in ZnO layers grown on sapphire (0001) surface,” Appl. Phys. Lett. 85, 4385 (2004).

Patents:

  1. Xiaolong Du, Zhaoquan Zeng, Hongtao Yuan, Handong Li, Qikun Xue, Jinfeng Jia, “High-vacuum in-situ refining apparatus for extracting high-purity material,” Patent No.: US2008257109-A1, Publication date: Oct. 23rd, 2008, Patent No.: US7753987-B2 Jul. 13th, 2010.
  2. Xiaolong Du, Xina Wang, Zhaoquan Zeng, Hongtao Yuan, Zengxia Mei, Qikun Xue, Jinfeng Jia, “Method for preparing high-quality zinc oxide single-crystal film on silicon substrate,” Patent No.: US20090291523 -A1, Nov. 26th, 2009.

Conference:

  1. (Talk) Zhaoquan Zeng, Adrian Podpirka, Steven Kirchoeffer, T. J. Asel, H. T. Gao, L. J. Brillson, “Native Point Defect Correlation with Microwave Properties of MBE-grown (Ba,Sr)TiO3 Thin Films,” 57th Electronic Materials Conference, Ohio State University, Columbus, OH, June 24-26, 2015.
  2. (Invited Talk) L.J. Brillson, M. M. Rutkowski, K. McNicholas, J. Cox, Z. Q. Zeng, and F. Tuomisto, “Control of Native Point Defects in Complex Oxides by Electromechanical Forces,”, Electronic Materials Nanotechnology Summer Meeting, Cancun, Mexico, June 10, 2014.
  3. (Invited Talk) L.J. Brillson, M. M. Rutkowski, K. McNicholas, J. Cox, Z.Q. Zeng, and F. Tuomisto, “Control of Native Point Defects in Complex Oxides by Electromechanical Forces,” Multifunctional Materials Workshop (MFM-9), Shimla, India, June 3, 2014.
  4. (Talk) Chen Li, Zhaoquan Zeng, Dongsheng Fan, Yusuke Hirono, Jiang Wu, Timothy A. Morgan, Xian Hu, Shuiqing Yu, Zhiming M. Wang, and Gregory J. Salamo, “Nanostructures induced by bismuth nano-droplets using molecular beam epitaxy,” 4th International Workshop on Bismuth-Containing Semiconductors: Growth, Properties and Devices, University of Arkansas, Arkansas, United States, July 14-17, 2013.
  5. (Talk) D. Fan, P. C. Grant, Z. Q. Zeng, X. Hu, C. Li, V. G. Dorogan, M. E. Hawkridge, Yu, I. Mazur, S.-Q. Yu, S. R. Johnson, Zh. M. Wang, and G. J. Salamo, “GaAsBi/GaAs Multiple Quantum Wells Grown by Molecular Beam Epitaxy,” 29th North American Molecular Beam Epitaxy Conference (NAMBE), Atlanta GA, October 14-17, 2012.
  6. (Talk) D. Fan, Z. Q. Zeng, X. Hu, V. G. Dorogan, Y. Hirono, C. Li, P. C. Grant, M. Benamara, M. E. Hawkridge, Yu, I. Mazur, S.-Q. Yu, S. R. Johnson, Zh. M. Wang, and G. J. Salamo, “High Optical Quality GaAsBi/GaAs/AlGaAs Separate Confinement Heterostructures,” 17th International Conference on Molecular Beam Epitaxy (MBE 2012), Nara, Japan, September 23-28, 2012.
  7. (Talk) D. Fan, Z. Q. Zeng, X. Hu, V. G. Dorogan, Y. Hirono, C. Li, P. C. Grant, M. Benamara, M. E. Hawkridge, Yu, I. Mazur, S.-Q. Yu, S. R. Johnson, Zh. M. Wang, and G. J. Salamo, “Molecular Beam Epitaxy Growth of GaAsBi/GaAs/AlGaAs Separate Confinement Heterostructures,” 3rd International Workshop on Bismuth-Containing Semiconductors (3rd BCS), Victoria B.C., Canada, July15-18, 2012.
  8. (Talk) Z. Q. Zeng, C. Li, D. S. Fan, Y. Hirono, T. A. Morgan, X. Hu, J. Wang, M. Singh, Zh. M. Wang, S. Q. Yu, A. Q. Guo and G. J. Salamo, “Fabrication of Bi2Te3 Nanodots by Droplet Epitaxy on GaAs Substrates,” APS March Meeting 2012, Boston, Feb. 27th ~Mar. 2nd, 2012.
  9. (Talk) D. S. Fan, Z. Q. Zeng, Zh. M. Wang, S. R. Johnson, S. Q. Yu and G. J. Salamo, “Molecular beam epitaxy grown GaInAsSbBi alloys on GaSb substrates for mid-infrared laser diode applications,” SPIE Photonics West 2012, San Francisco, California, Jan. 23nd ~26th, 2012.
  10. (Talk) Z. Q. Zeng, D. S. Fan, C. Li, Y. Hirono, T. A. Morgan, J. Wang, J. S. Lee, Zh. M. Wang, S. Q. Yu, A. Q. Guo and G. J. Salamo, “Epitaxial Growth of High-Quality Bi2Te3 and Sb2Te3 Thin Films on GaAs (111)”, 2011 MRS Fall Meeting, Boston, Nov. 28th ~Dec. 2nd, 2011.
  11. (Poster) T. A. Morgan, Z. Q. Zeng, R. J. Sleezer and G. J. Salamo, “Growth of Self-Assembled BaTiO3 Nanodots via Tensile Strain”, 2011 MRS Fall Meeting, Boston, Nov. 28th ~Dec. 2nd, 2011.
  12. (Poster) D. S. Fan, Z. Q. Zeng, V. G. Dorogan, Y. Hirono, C. Li, Y. I. Mazur, Zh. M. Wang, S. R. Johnson, S. Q.Yu and G. J. Salamo, “Bismuth Surfactant Mediated Growth of InAs Quantum Dots by Molecular Beam Epitaxy,” 2011 MRS Fall Meeting, Boston, Nov. 28th ~Dec. 2nd, 2011.
  13. (Talk) S. Q. Yu, S. R. Johnson, Zh. M. Wang, Z. Q. Zeng, G. J. Salamo, “Al free Mid-IR lasers using InGaAsSbBi material system,” International Workshop on 6.1Å II-VI and III-V Materials and their Integration, Tempe, Arizona, Nov. 8th ~9th, 2011.
  14. (Poster) Z. Q. Zeng, D. S. Fan, C. Li, Y. Hirono, T. A. Morgan, J. Wang, J. S. Lee, S. R. Johnson, A. Q. Guo, Zh. M. Wang, S. Q. Yu, G. J. Salamo, “MBE grown III-V Bi nanostructures and topological insulators,” International Workshop on 6.1Å II-VI and III-V Materials and their Integration, Tempe, Arizona, Nov. 8th ~9th, 2011.
  15. (Talk) D. Fan, Z. Zeng, V. G. Dorogan, Y. Hirono, C. Li, Y. I. Mazur, Z. M. Wang, S. R. Johnson, S.-Q. Yu and G. J. Salamo, “Photoluminescence and Surface Morphology Characterization of GaAsBi Grown on GaAs by Molecular Beam Epitaxy,” NAMBE 2011, August 14-17, 2011 University of California, San Diego, CA, 2011.
  16. (Poster) Z. Q. Zeng, Y. Z. Liu, X. L. Du, H. T. Yuan, Z. X. Mei, J. F. Jia, Q. K. Xue, Z. Zhang, “Surface modification of MgAl2O4 (111) for growth of high-Quality ZnO epitaxial film with atomically smooth surface,” The 4th International Workshop on ZnO and Related Materials, Giessen, Germany, Oct. 3, 2006

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