- Research Groups
- Area of Excellence Project
- Astronomy and Astrophysics
- Centre of Theoretical & Computational Physics
- Experimental Condensed Matter Physics Group
- Experimental High Energy Particle Physics Group
- Experimental Nuclear Physics Group
- Material Science Group
- Quantum Computing and Information Theory
- Theoretical Atomic Physics and Degenerate Quantum Gases
- Theoretical Condensed Matter Physics Group
- Prof. W. Yao and Prof. X.D. Cui’s paper titled ‘Valley polarization in MoS2 monolayers by optical pumping’ was highlighted in Ars Technica.
Material Science Group
|Transient setup and GaN:Co surface|
Mr. Ka Wo CHAN
Mr. Fahad AZAD (PhD)
Mr. Waqar AZEEM (PhD)
Mr. Jinglei CHEN (PhD)
Mr. Wei CHEN (PhD)
Ms. Yawei DAI (PhD)
Mr. Muyao GUO (PhD)
Mr. Lok Ping HO (PhD)
Ms. Xiaoqing HU (PhD)
Mr. Dong HUANG (PhD)
Mr. Weiyi HUANG (PhD)
Ms. Caiqin LUO (PhD)
Ms. Yaping QI (PhD)
Ms. Qian SUN (PhD)
Mr. Ho Won TAM (MPhil)
Mr. Hao TIAN (PhD)
Ms. Jian WANG (PhD)
Mr. Man Kwong WONG (PhD)
Mr. Yipu XIA (PhD)
Ms. Jiali ZENG (MPhil)
Ms. Junqiu ZHANG (PhD)
The material science group conducts researches of various materials in the form of thin films and nanostructures. Examples include perovskite transition metal oxides, transition metal dichalcogenides, wide bandgap semiconductors (ZnO and GaN, for example), topological insulators, organic and inorganic nanocomposites. The techniques involved include various high vacuum deposition systems (e.g., sputtering, thermal and e-beam evaporation, pulse laser ablation, chemical vapor deposition, and molecular-beam epitaxy), low temperature and high B field measurement facility, x-ray and electron diffraction, scanning probe microscopy, photoelectron and Auger electron spectroscopy, temperature dependent Hall, IV and CV measurements, UV/Vis/NIR spectrometers, etc.
Optoelectronics and Nanomaterials (A.B. Djurišić))
The research activities include fabrication and characterization of organic and organic/inorganic nanocomposite optoelectronic devices (organic light emitting diodes and solar cells), as well as fabrication and characterization of wide band gap semiconductor nanostructures. The laboratory is equipped with fume cupboards, tube furnaces, spin-coater, two thermal evaporators for fabrication of optoelectronic devices, and E-beam/sputtering deposition system, while characterization facilities include UV/Vis/NIR spectrometers for characterization of light emitting diodes and experimental setups for power conversion efficiency and external quantum efficiency measurements for solar cells. The study of organic optoelectronic devices aims at improving the understanding of the operating principles and processes taking place at organic/inorganic interfaces. The obtained results are then used for fabrication of devices with improved performance. The study of wide band gap nanostructures includes comprehensive investigation of influence of the fabrication conditions on structural and optical properties of the nanostructures, and exploring their possible use in energy and environmental applications.
Experimental Thin Film Studies (J. Gao)
The central aim of the Thin Film Laboratory is to study and develop thin films of novel materials and advanced microelectronic devices. The laboratory houses a wide range of state-of-the-art instrumentation for fabrication and characterization of thin films and advanced devices. The major items of equipment include various high vacuum deposition systems such as magnetron sputtering, e-beam evaporation, laser beam epitaxial, and pulse laser ablation; low temperature and high field measuring apparatus; x-ray diffraction system; scanning probe microscopy, as well as the clean room facilities for lithography. The research activities of this group are currently focused on the fabrication and characterization of thin films and hetero-structures of perovskite oxide materials. The on-going projects include study of the current induced ER effect in ABO3 compounds, metastability in thin films of manganite oxides, as well as investigation on the heterojunctions of various perovskite transition metal oxides.
Wide Band Gap Semiconductor Systems (C.C. Ling)
The current focused interests of the Material Physics Laboratory include:
(1) Defects in semiconductors: characterizations and identifications, defects influence on materials electrical, optical and magnetic properties, defect control, defects at semiconductor junctions;
(2) Electrical and optical properties of semiconductor system: deep level transient spectroscopy, temperature dependent Hall measurement, IV and CV measurements, luminescence spectroscopy;
(3) Positron annihilation spectroscopic study of vacancy type defects: These research activities are performed with the positron beam line located at the electron LINAC ELBE, Helmoltz Zentrum Dresden Rossendorf, Germany.
(4) Material physics of ZnO: p-type doping of ZnO, ZnO surface, homogeneous and hetero-junctions, film fabrication by pulsed laser deposition, defect characterization, electrical, optical and magnetic properties of ZnO related materials and structures.
Experimental Surface Science (M.H. Xie)
The surface science laboratory aims at understanding the processes and properties that occur at the boundary of materials - surface.
Current researches focus on the growth and surfaces of novel quantum materials, including topological insulators, transition-metal dichalcogenides and their hetero- and nano-structures.
• Molecular Beam Epitaxy (MBE) of ultrathin layers
MBE is one of the most versatile techniques to grow materials with precise control. It allows fabrication of artificial structures by combining different materials to form the so-called "quantum wells" and "superlattices". Quantum effects and new concepts in material sciences are thus explored for modern device applications.
• Growth kinetics and dynamics of MBE
The availability of surface sensitive techniques in MBE makes it best suited to investigating surface growth kinetics. The RHEED monitors the growing surface in real time, while STM/AFM visualizes the grown surface in real space at atomic scale. Surface morphology evolution during growth can thus be followed for growth kinetics and dynamics.
• Surface electronic properties of thin films
While STM/AFM reveals morphological and atomic structures of surfaces, scanning tunneling spectroscopy (STS) probes local electronic structures, such as the electronic density of states and the band dispersion relation. This is important to understand the various effects at atomic scale.
Some Representative Publications
Prof. A.B. Djurišić
“Is excess PbI2 beneficial for perovskite solar cell performance?”, F. Z. Liu, Q. Dong, M. K. Wong, A. B. Djurišić, A. Ng, Z. W. Ren, Q. Shen, C. Surya, W. K. Chan, J. Wang, A. M. C. Ng, C. Z. Liao, H. K. Li, K. M. Shih, C. R. Wei, H. M. Su, and J. F. Dai, Adv. Energy Mater, 6, 1502206 (2016)
“Hydrothermally synthesized CuxO as a catalyst for CO oxidation”, M.Y. Guo, F.Z. Liu, J.K. Tsui, A.A. Voskanyan, A.M.C. Ng, A.B. Djurišić, W.K. Chan, K.Y. Chan, C.Z. Liao, K.M. Shih and C. Surya, Journal of Materials Chemistry A, 3, 3627-3632 (2015)
“Is the Effect of Surface Modifying Molecules on Antibacterial Activity Universal for a Given Material?”, A. Hsu, F.Z. Liu, Y.H. Leung, A.P.Y. Ma, A.B. Djurišić, F.C.C. Leung, W.K. Chan and H.K. Lee, Nanoscale, 6, 10323-10331 (2014)
“Mechanisms of Antibacterial Activity of MgO: Non-ROS Mediated Toxicity of MgO Nanoparticles Towards Escherichia coli”, Y.H. Leung, A.M.C. Ng, X.Y. Xu, Z.Y. Shen, L.A. Gethings, M.T. Wong, C.M.N. Chan, M.Y. Guo, Y.H. Ng, A.B. Djurišić, P.K.H. Lee, W.K. Chan, L.H. Yu, D.L. Phillips, A.P.Y. Ma and F.C.C. Leung, Small, 10, 1171-1183 (2014)
“In situ synthesis of CuxO/SnOx/CNT and CuxO/SnOx/SnO2/CNT nanocomposite anodes for lithium ion batteries by a simple chemical treatment process”, X. Liu, F. Z. Liu, Q. Sun, A. M. C. Ng, A. B. Djurišić, M. H. Xie, C. Z. Liao, K. M. Shih,ACS Appl. Mater. & Interfaces , 6, 13478-13486 (2014)
For details, please refer to the Homepage of Optoelectronics and Nanomaterials Lab.
Prof. J. Gao
“Strain-induced photoconductivity in thin films of Co-doped amorphous carbon”, Y. C. Jiang and J. Gao, Scientific Reports, 4, 06738 (2014)
“Giant photoconductivity induced by Co nanoparticles in Co-doped amorphous carbon/silicon heterostructures”, Y. C. Jiang, J. F. Wang, and J. Gao, Carbon, 72, 106-113 (2014)
“Modulation of persistent photoconductivity by electric-field-controlled strain in thin films of La0.39Pr0.24Ca0.37MnO3”, J.F. Wang, Y.C. Jiang, Z.P. Wu, and J. Gao, Appl. Phys. Lett., 102, 071913 (2013)
“Positive colossal magnetoresistance observed in Co doped amorphous carbon/silicon heterostructures”, Y. C. Jian and J. Gao, Appl. Phys. Lett., 101, 182401 (2012)
“Phase competition induced nonlinear elastoresistance effect in thin films of Pr0.7Sr0.3MnO3”, J.F. Wang and J. Gao,Appl. Phys. Lett., 100, 131903 (2012)
“Strain-mediated electric-field control of photoinduced demagnetization in La0.8Ca0.2MnO3 thin films”, Guo E.J., Gao J, Lu HB,Appl. Phys. Lett., 98, 081903 (2011)
Dr. F.C.C. Ling
“Thermal evolution of defects in undoped zinc oxide grown by pulsed laser deposition”, Zilan Wang, Shichen Su, Francis Chi-Chung Ling, W. Anwand, and A. Wagner, J. Appl. Phys., 116, 033508 (2014)
“Impedance analysis of secondary phases in a Co-implanted ZnO single crystal”, M. Younas, L. L. Zou, M. Nadeem, Naeem-ur-Rehman, S. C. Su, Z. L. Wang, W. Anwand, A. Wagner, J. H. Hao, C. W. Leung, R. Lortz, and F. C. C. Ling, Phys. Chem. Chem. Phys., 16, 16030 (2014)
“Low-threshold lasing action in an asymmetric double ZnO/ZnMgO quantum well structure”, S.C. Su, H. Zhu, L.X. Zhang, M. He, L.Z. Zhao, S.F. Yu, J.N. Wang and F. C.C. Ling, Appl. Phys. Lett., 103, 131104 (2013)
“Current transport studies of ZnO/p-Si heterostructures grown by plasma immersion ion implantation and deposition”, X. D. Chen, C. C. Ling, S. Fung, C. D. Beling, Y. F. Mei, Ricky K. Y. Fu, G. G. Siu, Paul K. Chu,Appl. Phys. Lett., 88, 132104 (2006)
“Low energy electron irradiation induced deep level defects in 6H-SiC: The implication for the microstructure of the deep levels E1/E2”, X.D. Chen, C.L. Yang, M. Gong, W.K. Ge, S. Fung, C.D. Beling, J.N. Wang, M.K. Lui and C.C. Ling,Appl. Phys. Lett., 92, 125504 (2004)
Prof. M.H. Xie
“Observation of intervalley quantum interference in epitaxial monolayer tungsten diselenide”, H.J. Liu, J.L. Chen, H.Y. Yu, F. Yang, L. Jiao, G.B. Liu, W.K. Ho, C.L. Gao, J.F. Jia, W. Yao, M.H. Xie, Nat. Comm., 6, 8180 (2015)
“Line and point defects in MoSe2 bilayer studied by scanning tunneling microscopy and spectroscopy”, H.J. Liu, H. Zheng, F. Yang, L. Jiao, J.L. Chen, W.K. Ho, C.L. Gao, J.F. Jia, M.H. Xie, ACS Nano., 9, 6619 (2015)
“Molecular-beam epitaxy of monolayer and bilayer WSe2: a scanning tunneling microscopy / spectroscopy study and deduction of exciton binding energy”, H.J. Liu, L. Jiao, L. Xie, F. Yang, J.L. Chen, W.K. Ho, C.L. Gao, J.F. Jia, X.D. Cui, M.H. Xie, 2D Materials, 2, 034004 (2015)
“Dense network of one-dimensional midgap metallic modes in monolayer MoSe2 and their spatial undulations”, H.J. Liu, L. Jiao, F. Yang, Y. Cai, X. Wu, W.K. Ho, C.L. Gao, J.F. Jia, N. Wang, H. Fan, W. Yao, M.H. Xie, Physical Review Letters, 113, 066105 (2014)
“Single domain Bi2Se3 films grown on InP(111)A by molecular-beam epitaxy”, X. Guo, Z.J. Xu, H.C. Liu, B. Zhao, X.Q. Dai, H.T. He, J.N. Wang, H.J. Liu, W.K. Ho, M.H. Xie,Applied Physical Letters, 102, 151604 (2013)
“Anisotropic topological surface states on high-index Bi2Se3 films”, Z.J. Xu, X. Guo, M.Y. Yao, H.T. He, L. Miao, L. Jiao, H.C. Liu, J.N. Wang, D. Qian, J.F. Jia, W.K. Ho, M.H. Xie,Advanced Materials, 25, 1557 (2013)
“Superlattices of Bi2Se3/In2Se3: Growth Characteristics and Structural Properties”, Z.Y. Wang, X. Guo, H.D. Li, T.L. Wong, N. Wang and M.H. Xie, Applied Physics Letters, 99, 023112 (2011)
“The Van Der Waals Epitaxy of Bi2Se3 on the Vicinal Si(111) Surface: An Approach for Preparing High-quality Thin Films of a Topological Insulator”, ", H.D. Li, Z.Y. Wang, X. Kan, X. Guo, H.T. He, Z. Wang, J.N. Wang, T.L. Wong, N. Wang and M.H. Xie, New Journal of Physics, 12, 103038 (2010)
“Dislocation Network at InN/GaN Interface Revealed by Scanning Tunneling Microscopy”, Y. Liu, Y. Cai, L.X. Zhang, M.H. Xie, N. Wang, S.B. Zhang and H.S. Wu, Applied Physics Letters, 92, 231907 (2008)
“Growth Mode and Strain Evolution during InN Growth on GaN(0001) by Molecular-Beam Epitaxy”, Y.F. Ng, Y.G. Cao, M.H. Xie, X.L. Wang and S.Y. Tong, Applied Physics Letters, 81, 3960 (2002)
“Observation of 'Ghost' Islands and Surfactant Effect of Surface Ga Atoms during GaN Growth by MBE”, L.X. Zheng, M.H. Xie, S.M. Seutter, S.H. Cheung and S.Y. Tong, Physical Review Letters, 85, 2352 (2000)