scispace - formally typeset
Search or ask a question
Author

Chee Chung Wong

Bio: Chee Chung Wong is an academic researcher from Nanyang Technological University. The author has contributed to research in topics: Piezoresistive effect & Charge carrier. The author has an hindex of 5, co-authored 9 publications receiving 173 citations. Previous affiliations of Chee Chung Wong include Agency for Science, Technology and Research & Singapore Science Park.

Papers
More filters
Journal ArticleDOI
TL;DR: This report combined the electrical biasing with the application of mechanical stress, which impacts the charge carriers' concentration, to achieve an electrically controlled giant piezoresistance in nanowires.
Abstract: Herein we demonstrate giant piezoresistance in silicon nanowires (NWs) by the modulation of an electric field-induced with an external electrical bias. Positive bias for a p-type device (negative for an n-type) partially depleted the NWs forming a pinch-off region, which resembled a funnel through which the electrical current squeezed. This region determined the total current flowing through the NWs. In this report, we combined the electrical biasing with the application of mechanical stress, which impacts the charge carriers’ concentration, to achieve an electrically controlled giant piezoresistance in nanowires. This phenomenon was used to create a stress-gated field-effect transistor, exhibiting a maximum gauge factor of 5000, 2 orders of magnitude increase over bulk value. Giant piezoresistance can be tailored to create highly sensitive mechanical sensors operating in a discrete mode such as nanoelectromechanical switches.

113 citations

Journal ArticleDOI
TL;DR: Self-sealing fluidics channels with circular cross-sections having diameters ranging between 30 and 2000 nm on a 200 mm glass wafer through CMOS compatible processes offers a means of integrating electrochemical and optical sensing on the same platform, for biological research.
Abstract: We realized self-sealing fluidics channels with circular cross-sections having diameters ranging between 30 and 2000 nm on a 200 mm glass wafer through CMOS compatible processes. Lateral voids were narrowed and sealed with non-conformal plasma enhanced chemical vapour deposition (PECVD) of phospho silicate glass (PSG) along silicon oxide trenches on silicon wafers. Leveraging on the reflow properties of PSG, circular profiled-channels were formed after undergoing high temperature annealing. These devices were subsequently transferred onto a borosilicate glass substrate through anodic bonding, and a fully transparent microfluidic device was achieved with the complete removal of the handle silicon substrate. The process offers a means of integrating electrochemical and optical sensing on the same platform, for biological research.

27 citations

Journal ArticleDOI
TL;DR: In this paper, a membrane pressure sensor with embedded piezoresistive silicon nanowires (NW) has been demonstrated to have an ultra-sensitive response of ( Δ R / R ) / Δ P of 13 Pa −1, achieved through the effective tuning of the transverse electric field across the NW.

25 citations

Patent
31 May 2006
TL;DR: In this paper, the authors propose a device for analysing the status of a biological entity, which consists of a substantially transparent base substrate (10) having a recess defined by at least two opposing lateral walls and a base wall, a substantially opaque filler member (14) having at least a portion of the recess occupying the recess, a substantial transparent separation layer (15) disposed between the filler member and the base substrate, and a channel (16) defined in the filler members, wherein the channel comprises an inlet and an outlet, the inlet being arranged on a first
Abstract: A device for analysing the status of a biological entity. The device (10) comprises a substantially transparent base substrate (11) having a recess defined therein by at least two opposing lateral walls and a base wall, a substantially transparent filler member (14) having at least a portion thereof occupying the recess, a substantially transparent separation layer (12) disposed between the filler member and the base substrate, and a channel (16) defined in the filler member, wherein the channel comprises an inlet and an outlet, the inlet being arranged on a first lateral wall of the filler member, and the outlet being arranged on a second lateral wall of the filler member, said first lateral wall of the filler member being arranged in opposing relationship with the second lateral wall of the filler member, and at least a portion of the first and the second lateral walls of the filler member being at least substantially perpendicular to the opposing lateral walls defining the recess.

11 citations

Book ChapterDOI
01 Jan 2011
TL;DR: A biohybrid micro-device consisting of silicon nanowires as electromechanical strain sensors, embedded in a suspended doubly-clamped silicon dioxide (SiO2) microbridge for the investigation of cellular attachment and detachment dynamics is proposed.
Abstract: Cell adhesion and detachment are crucial components in cancer spreading, often leading to recurrence and patient death [1]. Probing the mechanical behavior at the whole cell level while the cell is undergoing spreading and detachment during would enhance our understanding on cancer metastasis. However, these processes are not well understood in a quantitative sense, especially for the cancer cells [2]. In this article, we propose a biohybrid micro-device for the investigation of cellular attachment and detachment dynamics. This device comprises of silicon nanowires as electromechanical strain sensors, embedded in a suspended doubly-clamped silicon dioxide (SiO2) microbridge (Fig. 1A & Fig. 2A) for breast cancer (MCF-7) cells seeding and attachment (Fig. 1B).

6 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this review, recent activities and achievements of nanofabrication for nanofluidic devices, especially those reported in the past four years are summarized and an inclusive guideline for materials and processes selection in the preparation of nanopores is provided.
Abstract: Thanks to its unique features at the nanoscale, nanofluidics, the study and application of fluid flow in nanochannels/nanopores with at least one characteristic size smaller than 100 nm, has enabled the occurrence of many interesting transport phenomena and has shown great potential in both bio- and energy-related fields. The unprecedented growth of this research field is apparently attributed to the rapid development of micro/nanofabrication techniques. In this review, we summarize recent activities and achievements of nanofabrication for nanofluidic devices, especially those reported in the past four years. Three major nanofabrication strategies, including nanolithography, microelectromechanical system based techniques, and methods using various nanomaterials, are introduced with specific fabrication approaches. Other unconventional fabrication attempts which utilize special polymer properties, various microfabrication failure mechanisms, and macro/microscale machining techniques are also presented. Based on these fabrication techniques, an inclusive guideline for materials and processes selection in the preparation of nanofluidic devices is provided. Finally, technical challenges along with possible opportunities in the present nanofabrication for nanofluidic study are discussed.

230 citations

Journal ArticleDOI
TL;DR: In this article, the authors present experimental results of the gauge factors obtained for various poly-types of SiC films and SiC nanowires, the related theoretical analysis, and an overview on the development of siC piezoresistive transducers.
Abstract: Silicon carbide (SiC) is one of the most promising materials for applications in harsh environments thanks to its excellent electrical, mechanical, and chemical properties. The piezoresistive effect of SiC has recently attracted a great deal of interest for sensing devices in hostile conditions. This paper reviews the piezoresistive effect of SiC for mechanical sensors used at elevated temperatures. We present experimental results of the gauge factors obtained for various poly-types of SiC films and SiC nanowires, the related theoretical analysis, and an overview on the development of SiC piezoresistive transducers. The review also discusses the current issues and the potential applications of the piezoresistive effect in SiC. [2015-0092]

196 citations

Journal ArticleDOI
TL;DR: Individual stressed NWs are recognized as an ideal platform for the exploration of strain-related electronic and optical effects and may contribute significantly to the realization of novel optoelectronic devices, strain-enhanced field-effect transistors (FETs), or highly sensitive strain gauges.
Abstract: In this Letter we present the electrical and electro-optical characterization of single crystalline germanium nanowires (NWs) under tensile strain conditions. The measurements were performed on vapor–liquid–solid (VLS) grown germanium (Ge) NWs, monolithically integrated into a micromechanical 3-point strain module. Uniaxial stress is applied along the ⟨111⟩ growth direction of individual, 100 nm thick Ge NWs while at the same time performing electrical and optical characterization at room temperature. Compared to bulk germanium, an anomalously high and negative-signed piezoresistive coefficient has been found. Spectrally resolved photocurrent characterization on strained NWs gives experimental evidence on the strain-induced modifications of the band structure. Particularly we are revealing a rapid decrease in resistivity and a red-shift in photocurrent spectra under high strain conditions. For a tensile strain of 1.8%, resistivity decreased by a factor of 30, and the photocurrent spectra shifted by 88 meV...

119 citations

Journal ArticleDOI
TL;DR: The working principles of several types of pressure sensors are briefly introduced, and the sizes, performances, manufacturing processes, structures, and materials of small pressure sensors used in the different fields are explained in detail, especially in the medical field.
Abstract: Miniature Microelectromechanical Systems (MEMS) pressure sensors possess various merits, such as low power consumption, being lightweight, having a small volume, accurate measurement in a space-limited region, low cost, little influence on the objects being detected. Accurate blood pressure has been frequently required for medical diagnosis. Miniature pressure sensors could directly measure the blood pressure and fluctuation in blood vessels with an inner diameter from 200 to 1000 m. Glaucoma is a group of eye diseases usually resulting from abnormal intraocular pressure. The implantable pressure sensor for real-time inspection would keep the disease from worsening; meanwhile, these small devices could alleviate the discomfort of patients. In addition to medical applications, miniature pressure sensors have also been used in the aerospace, industrial, and consumer electronics fields. To clearly illustrate the "miniature size", this paper focuses on miniature pressure sensors with an overall size of less than 2 mm × 2 mm or a pressure sensitive diaphragm area of less than 1 mm × 1 mm. In this paper, firstly, the working principles of several types of pressure sensors are briefly introduced. Secondly, the miniaturization with the development of the semiconductor processing technology is discussed. Thirdly, the sizes, performances, manufacturing processes, structures, and materials of small pressure sensors used in the different fields are explained in detail, especially in the medical field. Fourthly, problems encountered in the miniaturization of miniature pressure sensors are analyzed and possible solutions proposed. Finally, the probable development directions of miniature pressure sensors in the future are discussed.

98 citations