Author
Shuit-Tong Lee
Other affiliations: University of British Columbia, Hong Kong University of Science and Technology, University of Western Ontario ...read more
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 published on a yearly basis
Papers
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TL;DR: In this article, a direct ion beam deposition of carbon films on silicon in the ion energy range of 15-500 eV and temperature range of 25-800degrees-C has been studied.
Abstract: Direct ion beam deposition of carbon films on silicon in the ion energy range of 15-500 eV and temperature range of 25-800-degrees-C has been studied. The work was carried out using mass-separated C+ and CH3+ ions under ultrahigh vacuum. The films were characterized with x-ray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy, and transmission electron diffraction analysis. In the initial stage of the deposition, carbon implanted into silicon induced the formation of silicon carbide, even at room temperature. Further carbon ion bombardment then led to the formation of a carbon film. The film properties were sensitive to the deposition temperature but not to the ion energy. Films deposited at room temperature consisted mainly of amorphous carbon. Deposition at a higher temperature, or post-deposition annealing, led to the formation of microcrystalline graphite. A deposition temperature above 800-degrees-C favored the formation of microcrystalline graphite with a preferred orientation in the (0001) direction. No evidence of diamond formation in these films was observed.
43 citations
TL;DR: Physical and chemical vapor deposition approaches of growing thick cubic boron nitride (cBN) films needed for practical applications are reviewed in this article, where the interfacial soft hexagonal/amorphous BN/aBN layers and large stress associated with cBN deposition are suppressed through reduction of ion energy, deposition at elevated temperatures, post-deposition treatment, use of buffer layers and introduction of halogen chemistry.
42 citations
TL;DR: In this article, the effect of cesium carbonate doping on the electron transport properties of 4,7-diphenyl-1, 10-phenanthroline (BPhen) layer has been investigated in organic light-emitting diodes (OLEDs).
Abstract: The effect of cesium carbonate (Cs2CO3) doping on the electron transport properties of 4,7-diphenyl-1, 10-phenanthroline (BPhen) layer has been investigated in organic light-emitting diodes (OLEDs). Temperature-dependent admittance spectroscopy studies show that the incorporation of Cs2CO3 from 0 to 42 wt. % can decrease the activation energy of the BPhen layer from 1.3 to 0.18 eV, resulting in the enhanced electron injection and transport with respect to reduced injection barrier and increased conductivity of the BPhen layer. This is consistent with the performance improvement in OLEDs, which yields better electrical characteristics and enhanced luminance efficiency.
42 citations
TL;DR: In this paper, a periodically twinned ZnSe/SiO2 nanowire with a sphalerite crystal structure and a common growth direction was studied using scanning electron microscopy (SEM), TEM, and selected area electron diffraction (SAED).
Abstract: Nanoscaled coaxial materials with a periodically twinned ZnSe single crystal core and an amorphous silicon dioxide shell were synthesized by a simple thermal evaporation process. As-fabricated ZnSe/SiO2 core/shell nanowires and nanoribbons were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a selected area electron diffraction (SAED) pattern. The periodically twinned ZnSe core with a twinning period of about 10−30 nm has a sphalerite crystal structure and a common growth direction of {11-1]. The amorphous SiO2 shell has a thickness of about 5 nm. The formation mechanism can be explained by the surface pressure stress from SiO2 shell to ZnSe core at the solid/liquid interface. The materials show strong cathodoluminescence (CL) related to the mixed light emission composed of band gap emission and defect emission. The single periodically twinned ZnSe/SiO2 nanowire has pronounced a photoconduction effect with a fast response time. The results suggest that the per...
42 citations
TL;DR: CdS nanoribbons-based memory phototransistors with high responsivity and detectivity are reported that can detect weak light of 6 nW/cm2 and can enable memory based photodetection by charge-storage accumulative effect.
Abstract: Ultraweak light detectors have wide-ranging important applications such as astronomical observation, remote sensing, laser ranging, and night vision. Current commercial ultraweak light detectors are commonly based on a photomultiplier tube or an avalanche photodiode, and they are incompatible with microelectronic devices for digital imaging applications, because of their high operating voltage and bulky size. Herein, we develop a memory phototransistor for ultraweak light detection, by exploiting the charge-storage accumulative effect in CdS nanoribbon. The memory phototransistors break the power law of traditional photodetectors and follow a time-dependent exponential-association photoelectric conversion law. Significantly, the memory phototransistors exhibit ultrahigh responsivity of 3.8 × 109 A W−1 and detectivity of 7.7 × 1022 Jones. As a result, the memory phototransistors are able to detect ultraweak light of 6 nW cm−2 with an extremely high sensitivity of 4 × 107. The proposed memory phototransistors offer a design concept for ultraweak light sensing devices. CdS nanostructures can enable memory based photodetection by charge-storage accumulative effect. Here, the authors report CdS nanoribbons-based memory phototransistors with high responsivity of 3.8 × 109 A/W and detectivity of 7.7 × 1022 Jones that can detect weak light of 6 nW/cm2.
42 citations
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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
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
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
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
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