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Shuit-Tong Lee

Bio: Shuit-Tong Lee is an academic researcher from Soochow University (Suzhou). The author has contributed to research in topics: Silicon & Nanowire. The author has an hindex of 138, co-authored 1121 publications receiving 77112 citations. Previous affiliations of Shuit-Tong Lee include University of British Columbia & Hong Kong University of Science and Technology.
Topics: Silicon, Nanowire, OLED, Electroluminescence, Diamond


Papers
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Journal ArticleDOI
31 Mar 2011-ACS Nano
TL;DR: Calculations show that the amorphous silicon photonic crystals embedded in multiple metallo-dielectric (MD) units can significantly increase the electromagnetic fields at the air-dieslectric interface, leading to remarkable Raman enhancement.
Abstract: Metallo-dielectric photonic crystals (MDPCs) are used as ultrasensitive molecular detectors for concentrations down to picomolar level based on surface-enhanced Raman spectroscopy (SERS). Calculations show that the amorphous silicon photonic crystals (a-Si PCs) embedded in multiple metallo-dielectric (MD) units can significantly increase the electromagnetic fields at the air−dielectric interface, leading to remarkable Raman enhancement. Corresponding experiments show the multiple MDPC structures can serve as an ultrasensitive SERS substrate with excellent reproducibility and stability, capable of quantitative analysis down to 10 pM level. The MDPC structure can be generalized to other applications, such as plasmonic devices, ultrasensitive sensors, and nanophotonic systems.

46 citations

Journal ArticleDOI
TL;DR: In this paper, the paramagnetic defects in and on Si nanowires obtained by oxide-assisted growth were studied by conventional electron spin resonance spectroscopy, and three different defects were found: Dangling bonds or Pb-centers with g=2.0065, located at the interface of the crystalline core to the surrounding oxide, E′-centrs with g =2.0005, and EX-center with g>2.004, located in the oxide.
Abstract: The paramagnetic defects in and on Si nanowires (SiNWs) obtained by oxide-assisted growth were studied by conventional electron spin resonance spectroscopy. For the as-grown nanowires, three different defects were found: Dangling bonds or Pb-centers with g=2.0065, located at the interface of the crystalline core to the surrounding oxide, E′-centers with g=2.0005 and EX-centers with g=2.00252, located in the oxide. For the EX-centers, the characteristic hyperfine lines separated by 16.4G were detected. The as-grown SiNWs showed a spin density of about 1018cm−3. H termination of the nanowires via hydrofluoric acid decreases the spin density drastically to 3×1016cm−3. The optical absorption spectra of SiNWs determined by photothermal deflection spectroscopy are comparable to those of microcrystalline silicon and show a similar decrease of defect density upon H termination.

46 citations

Journal ArticleDOI
TL;DR: In this paper, the authors employ density functional theory within the generalized-gradient approximation to investigate infinitely long [0001] ZnO nanowires with triangular cross-sections, and report on atomic relaxations, formation energies, and electronic structure.
Abstract: The authors employ density functional theory within the generalized-gradient approximation to investigate infinitely long [0001] ZnO nanowires. The authors report on atomic relaxations, formation energies, and electronic structure of bare and hydrogen passivated ZnO wires with triangular cross sections. The authors find that surface reconstruction plays an important role in stabilizing the nanowires. The authors have shown that the band gap can be tuned by changing the wire diameter and by passivating with hydrogen. While bare and completely passivated wires are semiconducting, wires with intermediate hydrogen passivation exhibit metallic behavior.

46 citations

Journal ArticleDOI
TL;DR: In this paper, the bipolar carrier transport properties of 2,7-dipyrenyl-9,9′-dimethyl-fluorene (DPF) have been elucidated by using different device structures.
Abstract: Excellent bipolar carrier transport properties of 2,7-dipyrenyl-9,9′-dimethyl-fluorene (DPF) have been elucidated by using different device structures. A nondoped device using DPF as host emitter showed highly-efficient blue emission with a maximum efficiency of 6.0cd∕A and CIE coordinates of x=0.15 and y=0.19. Another device based on rubrene-doped DPF as emission layer gave pure high-efficiency white emission with good color stability, a maximum efficiency of 10.5cd∕A, and CIE coordinates of x=0.28 and y=0.35. The excellent bipolar transport capability and high performance as both emitter and host suggest that DPF is an efficient and versatile material for various applications in organic light-emitting devices.

45 citations

Journal ArticleDOI
01 Jul 2012-Carbon
TL;DR: In this article, a generic strategy to make hybrids incorporating metal nanoparticles and carbon nanosupports with large surface area is reported, which is a one-step, universal approach totally free of additives and by-products.

45 citations


Cited by
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Journal ArticleDOI
11 Oct 2012-Nature
TL;DR: This work reviews recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.
Abstract: Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

7,987 citations

Journal ArticleDOI
TL;DR: The theoretical charge capacity for silicon nanowire battery electrodes is achieved and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.
Abstract: There is great interest in developing rechargeable lithium batteries with higher energy capacity and longer cycle life for applications in portable electronic devices, electric vehicles and implantable medical devices. Silicon is an attractive anode material for lithium batteries because it has a low discharge potential and the highest known theoretical charge capacity (4,200 mAh g(-1); ref. 2). Although this is more than ten times higher than existing graphite anodes and much larger than various nitride and oxide materials, silicon anodes have limited applications because silicon's volume changes by 400% upon insertion and extraction of lithium which results in pulverization and capacity fading. Here, we show that silicon nanowire battery electrodes circumvent these issues as they can accommodate large strain without pulverization, provide good electronic contact and conduction, and display short lithium insertion distances. We achieved the theoretical charge capacity for silicon anodes and maintained a discharge capacity close to 75% of this maximum, with little fading during cycling.

6,104 citations

Journal ArticleDOI
09 Mar 2001-Science
TL;DR: The beltlike morphology appears to be a distinctive and common structural characteristic for the family of semiconducting oxides with cations of different valence states and materials of distinct crystallographic structures, which could be an ideal system for fully understanding dimensionally confined transport phenomena in functional oxides.
Abstract: Ultralong beltlike (or ribbonlike) nanostructures (so-called nanobelts) were successfully synthesized for semiconducting oxides of zinc, tin, indium, cadmium, and gallium by simply evaporating the desired commercial metal oxide powders at high temperatures. The as-synthesized oxide nanobelts are pure, structurally uniform, and single crystalline, and most of them are free from defects and dislocations. They have a rectanglelike cross section with typical widths of 30 to 300 nanometers, width-to-thickness ratios of 5 to 10, and lengths of up to a few millimeters. The beltlike morphology appears to be a distinctive and common structural characteristic for the family of semiconducting oxides with cations of different valence states and materials of distinct crystallographic structures. The nanobelts could be an ideal system for fully understanding dimensionally confined transport phenomena in functional oxides and building functional devices along individual nanobelts.

5,677 citations

Journal ArticleDOI
TL;DR: The state of the art, future directions and open questions in Raman spectroscopy of graphene are reviewed, and essential physical processes whose importance has only recently been recognized are described.
Abstract: Raman spectroscopy is an integral part of graphene research. It is used to determine the number and orientation of layers, the quality and types of edge, and the effects of perturbations, such as electric and magnetic fields, strain, doping, disorder and functional groups. This, in turn, provides insight into all sp(2)-bonded carbon allotropes, because graphene is their fundamental building block. Here we review the state of the art, future directions and open questions in Raman spectroscopy of graphene. We describe essential physical processes whose importance has only recently been recognized, such as the various types of resonance at play, and the role of quantum interference. We update all basic concepts and notations, and propose a terminology that is able to describe any result in literature. We finally highlight the potential of Raman spectroscopy for layered materials other than graphene.

5,673 citations

Journal ArticleDOI
TL;DR: This paper presents a meta-analysis of the chiral stationary phase transition of Na6(CO3)(SO4)2, a major component of the response of the immune system to Na2CO3.
Abstract: Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

5,658 citations