Dr. S. J. Xu (徐士杰)

Professor, Department of Physics, the University of Hong Kong



Room 316,

Chong Yuet Ming Physics Building,

The University of Hong Kong

Tel : (852) 2241 5636 

Fax: (852) 2559 9152
E-mail: sjxu@hku.hk


Homepage of Dr. S.J. Xu's Research Group.







Research Interests




Short Biography:  >>>[Detailed CV]




  • 1984: B.S., Hebei Institute of Technology, Tianjin, China.
  • 1989: M.S., Xi'an Jiaotong University, Xi'an, China
  • 1993: PhD., Xi'an Jiaotong University, Xi'an, China.

    Career history:


  • 1984.8-1986.8: Processing Engineer, Renqiu Semiconductor Device Co., Hebei, China.
  • 1992.1-1992.12: Research Assistant, National Laboratory for Superlattices and Microstructures (NLSM), Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
  • 1993.1-1995.5: Postdoctoral Research Fellow, NLSM, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
  • 1995.5-1996.12: NSTB Postdoctoral Fellow, Department of Electrical Engineering, National University of Singapore, Singapore.
  • 1997.1-1998.12: Research Fellow, Institute of Materials Research and Engineering, National University of Singapore, Singapore.
  • 1999.1-2001.6: Research Assistant Professor, Departments of Physics and Chemistry, The University of Hong Kong, Hong Kong.
  • 2001.7-2007.6: Assistant Professor, Department of Physics, The University of Hong Kong, Hong Kong.
  • 2007.7-2014.6: Associate Professor, Department of Physics, The University of Hong Kong, Hong Kong.
  • 2014.7-present: Professor, Department of Physics, The University of Hong Kong, Hong Kong.


    Selected Representative Publications:


    1. Jun Wang, Changcheng Zheng, Jiqiang Ning, Lixia Zhang, Wei Li, Zhenhua Ni, Yan Chen, Jiannong Wang, and Shijie Xu, "Luminescence signature of free exciton dissociation and liberated electron transfer across the junction of graphene/GaN hybrid structure", Scientific Reports, 5, 7687 (2015), DOI: 10.1038/srep07687.
    2. J.Q. Ning, S.J. Xu, Z. Deng and Z.C. Su,"Polarized and non-polarized photoluminescence of GaInP2 alloy with partial CuPt-type atomic ordering: ordered domains vs. disordered regions", Journal of Materials Chemistry C, 2, 6119-6124 (2014), DOI: 10.1039/C4TC00450G.
    3. C. C. Zheng, S. J. Xu, J. Q. Ning, Y. N. Chen, F. Zhang, and C. M. Che, "Temperature dependent distinct coupling and dispersions of heavy- and light-hole excitonic polaritons in ZnO", Applied Physics Letters 100, 221105:1-4 (2012)
    4. C. C. Zheng, S. J. Xu, J. Q. Ning, Y. N. Chen, B. K. Li, J. N. Wang, and C. M. Che, "Formation dynamics of excitons and temporal behaviors of Fano resonance due to the exciton-impurity-phonon configuration interaction in ZnO", Journal of Physical Chemistry A 116, 381-385 (2012)
    5. J. H. Zhu, J. Q. Ning, C. C. Zheng, S. J. Xu, S. M. Zhang, and Hui Yang, "Localized surface optical phonon mode in the InGaN/GaN multiple-quantum-wells nanopillars: Raman spectrum and imaging", Applied Physics Letters 99, 113115:1-3 (2011)
    6. S. L. Shi and S. J. Xu, "Determination of effective mass of heavy hole from phonon-assisted excitonic luminescence spectra in ZnO", Journal of Applied Physics 109, 053510:1-4 (2011)
    7. S. L. Shi, G. Q. Li, S. J. Xu, Y. Zhao, and G. H. Chen, Green luminescence band in ZnO: Fine structures, electron-phonon coupling and temperature effect. Journal of Physical Chemistry B, 110:10475, 2006.
    8. S. J. Xu, S. J. Xiong, and S. L. Shi, Resonant coupling of bound excitons with LO phonons in ZnO: Excitonic polaron states and Fano interference. Journal of Chemical Physics, 123:221105, 2005.
    9. D. C. Dai, S. J. Xu, S. L. Shi, M. H. Xie, and C. M. Che, Efficient multi-photon absorption induced luminescence in single crystalline ZnO at room temperature. Optics Letters, 30:3377, 2005.
    10. “A Model for Steady-State Luminescence of Localized-State Ensemble”, Q. Li, S.J. Xu, M.H. Xie, and S.Y. Tong, Europhysics Letters, 71, 994 (2005).
    11. “Spectral Features of LO Phonon Sidebands in Luminescence of Free Excitons in GaN”, S.J. Xu, G.Q. Li, S.J. Xiong, S.Y. Tong, C.M. Che, W. Liu, and M.F. Li,  Journal of Chemical Physics, 122, 244712 (2005).
    12. “Stress and Its Effect on Optical Properties of GaN Epilayers Grown on Si(111), 6H-SiC(0001), and c-Plane Sapphire”, D.G. Zhao, S.J. Xu, M.H. Xie, S.Y. Tong, and H. Yang,  Applied Physics Letters, 83, 677 (2003).
    13. “Direct Determination of Free Exciton Binding Energy from Phonon-Assisted Luminescence Spectra in GaN Epilayers”, S.J. Xu, W. Liu, and M.F. Li, Applied Physics Letters, 81, 2959 (2002).
    14. “Thermal Redistribution of Localized Excitons and Its Effect on The Luminescence Band in InGaN Ternary Alloys”, Q. Li, S.J. Xu, W.C. Cheng, M.H. Xie, S.Y. Tong, C.M. Che, and H. Yang,  Applied Physics Letters, 79, 1801 (2001).
    15. "Effect of Temperature on Longitudinal Optical Phonon-assisted Luminescence in Heteroepitaxial GaN Epilayer", S.J. Xu, W. Liu and M.F. Li, Applied Physics Letters, 77, 3376 (2000).
    16. "X-ray Diffraction and Optical Characterization of Interdiffusion in Self-assembled InAs/GaAs Quantum Dot Superlattices", S.J. Xu, H. Wang, Q. Li, M.H. Xie, X.C. Wang, W.J. Fan and S.L. Feng, Applied Physics Letters, 77, 2130 (2000).
    17. “Time-Resolved Photoluminescence Spectra of Strong Visible Light-Emitting SiC Nanocrystalline Films on Si Deposited by Electron-Cyclotron-Resonance Chemical Vapor Deposition”, S.J. Xu, M.B. Yu, Rusli, S.F. Yoon, and C.M. Che,  Applied Physics Letters, 76, 2550 (2000).
    18. "Characteristics of InGaAs Quantum Dot Infrared Photodetector", S.J. Xu, S.J. Chua, T. Mei, X.C. Wang, X.H. Zhang, G. Karunasiri, W.J. Fan, C.H. Wang, J. Jiang, S. Wang, and X.G. Xie, Applied Physics Letters, 73, 3153 (1998).
    19. "Luminescence Characteristics of Impurities-activated ZnS Nanocrystals Prepared in Microemulsion with Hydrothermal Treatment", S.J. Xu, S.J. Chua, B. Liu, L.M. Gan, C.H. Chew and G.Q. Xu, Applied Physics Letters, 73, 478 (1998).
    20. "Effects of Rapid Thermal Annealing on Structure and Luminescence of Self-assembled InAs/GaAs Quantum Dots", S.J. Xu, X.C. Wang, S.J. Chua, C.H. Wang, W.J. Fan, J. Jiang, and X.G. Xie, Applied Physics Letters, 72, 3335 (1998).
    21. "Observation of Optically-Active Metastable Defects in Undoped GaN Epilayers", S.J. Xu, G. Li, S.J. Chua, X.C. Wang and W. Wang, Applied Physics Letters, 72, 2451 (1998).




    Invited talks:


    1. S.J. Xu, “Evolution of Surface Morphology, Stress and Defect States with Thickness of GaN Films Directly Grown on Flat 6H-SiC”, invited talk in Second Vacuum and Surface Sciences Conference of Asia and Australia, Hong Kong, Aug. 26-30, 2002.
    2. S.J. Xu, “Ultrafast Coherent Dynamics of Carriers in GaN”, invited talk in 2nd International Symposium on Ultrafast Phenomena and Terahertz Waves (ISUPTW2004), Shanghai, May 11-13, 2004.
    3. S.J. Xu, “Exciton-LO Phonon Interaction and Fano-type Quantum Interference in Luminescent Spectra of GaN”, invited talk in International Conference on Optoelectronics and Spectroscopy of Nano-Structured Thin Films and Materials (ICOSFM2004), Beijing, Aug. 2-5, 2004.
    4. G.H. Li, F.H. Su, B.S. Ma, K. Ding, S.J. Xu, and W. Chen, “Photoluminescence of doped ZnS nanoparticles under hydrostatic pressure”, invited talk in 11th International Conference on High Pressure Semiconductor Physics, Berkeley, USA, Aug. 2004.
    5. S.J. Xu, “Fano Resonance in Phonon-Assisted Photoluminescence Spectra of Widegap Polar Semiconductors”, invited talk in the 20th Congress of the International Commission for Optics (ICO20), Changchun, Aug. 21-26, 2005.
    6. S.J. Xu, “On the luminescence of localized-state ensemble”, invited talk in the Annual Meeting of Chinese Physics Society, Wuhan, Sept. 2005.
    7. S.J. Xu, “Two-Photon Absorption Induced Luminescence and Carrier Dynamics in InGaN/GaN Quantum Well Structures”, invited talk in the HKU-ICCAS Workshop on Molecular Functional Materials, Hong Kong, Dec. 2005.
    8. S.J. Xu, “Fs-multi-photon-excited fluorescence and carrier dynamics in ZnO”, invited talk in the 4th Asia Conference on Ultrafast Phenomena, Hong Kong, Jan. 8-11, 2006.
    9. S.J. Xu, “New Type of Fano Resonance in Electron Tunneling through a Doped Superlattice”, invited talk in the Annual Meeting of Chinese Physics Society, Beijing, Sept. 2006.
    10. S.J. Xu, “Luminescence imaging and blinking behavior of individual InGaN nanoclusters formed in GaN matrix”, invited talk in the 6th Asia-Pacific Conference on Near-Field Optics (APNFO6), Yellow Mountain, June 13-17, 2007.
    11. S.J. Xu, “Two-photon photoluminescence of InGaN/GaN multiple quantum wells”, invited talk in the International Conference on Materials for Advanced Technologies 2007 (ICMAT2007), Singapore, July 1-6, 2007.
    12. S.J. Xu, “Exciton-biexciton dynamics in InGaAs quantum wells studied by time-resolved Kerr rotation spectroscopy”, invited talk in the 23rd Progress in Electromagnetics Research Symposium, Hangzhou, Mar. 24-28, 2008.
    13. S.J. Xu, “Controlled Optical Injections and Initial Coherent Dynamics of Electron Spins in Semiconductor Quantum Disks”, invited talk in the 6th Asian Conference on Ultrafast Phenomena, Taipei, Jan. 11-13, 2010.
    14. S.J. Xu, “Luminescence imaging and blinking behavior of individual InGaN nanoclusters formed in GaN matrix”, invited talk in the 28th Progress in Electromagnetics Research Symposium, Boston, MA, USA, July 5-8, 2010.
    15. S.J. Xu, “New surface optical phonon mode and Raman imaging in InGaN/GaN MQW nanopillars”, invited talk in the 8th Cross-Strait Workshop on Nano Science & Technology, Hong Kong, Dec. 20-22, 2010.
    16. S.J. Xu, et al., “Enhanced Femtosecond Second Harmonic Generation in Thin ZnO Crystal Hollow Rods”, invited talk in the OSA-IEEE-COS Topical Meeting on Advances In Optoelectronics & Micro/Nano-Optics, Guangzhou, Dec. 3-6, 2010.
    17. S.J. Xu, “Exciton-Phonon-Impurity Interactions and Optical Properties in ZnO”, invited talk in the 18th Semiconductor Physics Conference, Huhehot, Aug. 20-26, 2011.
    18. S.J. Xu, “Raman enhancement effect in self-assembled Si nanoclusters grown on SiC”, invited talk in 2nd International Conference on Frontiers of Plasmonics (FOP2), Chengdu, Apr. 8-12, 2012.
    19. S.J. Xu, “Influence of Internal Strain and External Pressure on Electronic States and Optical Transitions in Self-assembled InxGa1-xAs /GaAs Quantum Dots”, invited talk in the 9th Cross Strait Workshop on Nano Science and Technology, Tainan, Taiwan, Apr. 22-25, 2012.
    20. S.J. Xu, “Exciton formation dynamics and temporal behavior of many-body Fano resonance in ZnO”, invited talk in West Photonics 2013, Xi’an, Oct. 18-19, 2013.
    21. S.J. Xu, “Polarized Photoluminescence and Carrier Localization of GaInP2 Alloy with Partial CuPt-type Atomic Ordering”, invited talk in THE 17TH ANNUAL CONFERENCE OF THE PHYSICAL SOCIETY OF HONG KONG, Hong Kong, June 7, 2014.
    22. S.J. Xu, “Carrier Localization and Polarized Photoluminescence of GaInP2 Alloy with Spontaneous Atomic Ordering”, invited talk in the 4th Advances in Optoelectronics and Micro/nano-optics, Xi’an, Sept. 17-20, 2014.
    23. S.J. Xu, “Carrier Diffusion and Mid-Way Recombination in GaInP2/GaAs Multijunction Photovoltaic Devices”, invited talk in the Asia Communications and Photonics Conference, Shanghai, Nov. 11-14, 2014.


    Grants Awarded since 1999


  • RGC-CERG Grant of Hong Kong, 2004-07, "Optical Properties and Electronic Structures of InGaAs/GaAs Self-assembled Quantum Dots with High Sheet Density" (HK$455,800). (on-going, as PI).
  • Small Project Funding of HKU, 2004, "Multiphoton excited photoluminescence and coherent spectra in wide gap semiconductors" (HK$50,000). (on-going, as PI).
  • Seed Funding Programme for Basic Research of HKU, 2004, "Optical Characterization of Cubic Phase GaN Epilayers Grown on 6H-SiC Substrates" (HK$90,000). (on-going, as PI)
  • RGC-CERG Grant of Hong Kong, 2003-06, "Comprehensive Spectroscopy Investigations of Blue and Green InGaN/GaN Light-Emitting Diode Structures with Multi-Quantum-Wells" (HK$380,000). (on-going, as PI).
  • Large-Item Equipment Funding of HKU, 2002-05, "Variable-Temperature Near-Field Spectromicroscopy: A Low-Temperature Nano-Optical Spectroscopy/Microscopy Facility for Optical Characterization of Nanostructured Materials and Single Molecules" (HK$2,640,000). (completed, as PI).
  • Seed Funding Programme for Basic Research of HKU, 2002, "Optical Properties of Individual Self-assembled InGaAs/GaAs Quantum Dots" (HK$100,000). (completed, as PI).
  • RGC(HK)/NSFC(Mainland) Joint Research Scheme, 2001-03, "Thin Film Synthesis and Device Processing of Blue-light Laser and LED Materials by MBE and MOCVD" (HK$560,000). (completed, as Co-I).
  • Seed Funding Programme for Basic Research of HKU, 2001, "Optical Properties of Wide-gap InGaN Ternary Semiconductors" (HK$100,000). (completed, as PI).
  • RGC Grant of Hong Kong, 2001-04, "Ultra-fast Laser Facility for Investigations of Novel Electronic Excited States and Intermediates in Inorganic Photochemistry, Semiconductor Materials and Nanomaterials" (HK$3.6M), supported by Central Allocation Scheme. (completed, as Co-I).
  • Research Initiation Programme of HKU, 1999, "Thermal annealing effects on structure and optical properties of self-organized semiconductor quantum dot structures", (HK$12,000). (completed, as PI).