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Proceedings ArticleDOI

Transport Characteristics of Si Nanowires in Bulk Silicon and SOI Wafers

27 Mar 2006-Vol. 2006, pp 67-70
TL;DR: In this paper, single or double vertically self-aligned wires were obtained depending on the bulk or SOI wafer used and also on the depth of silicon beam etched, which can be converted to circular shape by annealing at high temperatures, exploiting the visco-elastic properties of SiO 2 and Si.
Abstract: Silicon nanowires (SiNW) were fabricated on bulk Silicon and SOI wafers by means of conventional Si process technology. The nanowires were formed by stress-limited oxidation of Si beams pre-patterned on the wafer. Single or double vertically self-aligned wires were obtained depending on the bulk or SOI wafer used and also on the depth of silicon beam etched. The resulting nanowires exhibit triangular cross-section that can be converted to circular shape by annealing at high temperatures, exploiting the visco-elastic properties of SiO 2 and Si. Electrical measurements on single nanowire show that the resistance scales with length demonstrating consistent cross-sectional dimension in wires of different length. The nanowires formed on SOI wafers were also characterized as channels in FET configuration, using substrate as gate electrode. This technique can be exploited for realizing several nano-electronics, NEMS and biosensor applications in bulk silicon or SOI wafers, all in a CMOS compatible manner.
Citations
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Patent
11 Oct 2007
TL;DR: In this paper, the authors present a system for evaluating optical and electrical manufacturing criteria for a transparent conductor, including a database including stored reference transparent conductor data, and a controller subsystem configured to compare input acceptance manufacturing criteria.
Abstract: Systems, devices, and methods for designing and/or manufacturing transparent conductors. A system is operable to evaluate optical and electrical manufacturing criteria for a transparent conductor. The system includes a database including stored reference transparent conductor data, and a controller subsystem configured to compare input acceptance manufacturing criteria for a transparent conductor to stored reference transparent conductor data.

41 citations

Patent
11 Aug 2006
TL;DR: In this paper, a method of fabricating a sensor comprising a nanowire on a support substrate with a first semiconductor layer arranged on the support substrate is described, in which the fin structure is formed from the first layer of a semiconductor and the fin is then oxidized to form the fin.
Abstract: A method of fabricating a sensor comprising a nanowire on a support substrate with a first semiconductor layer arranged on the support substrate is disclosed. The method comprises forming a fin structure from the first semiconductor layer, the fin structure comprising at least two supporting portions and a fin portion arranged there between; oxidizing at least the fin portion of the fin structure thereby forming the nanowire being surrounded by a first layer of oxide; and forming an insulating layer above the supporting portions; wherein the supporting portions and the first insulating layer form a microfluidic channel. A nanowire sensor is also disclosed. The nanowire sensor comprises a support substrate, a semiconducting fin structure arranged on the support substrate, the fin structure comprising at least two semiconducting supporting portions and a nanowire arranged there between; and a first insulating layer on a contact surface of the supporting portions; wherein the supporting portions and the first insulating layer form a microfluidic channel.

28 citations

Patent
11 Oct 2007
TL;DR: In this paper, the authors present a system for evaluating optical and electrical manufacturing criteria for a transparent conductor, including a database including stored reference transparent conductor data, and a controller subsystem configured to compare input acceptance manufacturing criteria.
Abstract: Systems, devices, and methods for designing and/or manufacturing transparent conductors having nanowires. A system is operable to evaluate optical and electrical manufacturing criteria for a transparent conductor. The system includes a database including stored reference transparent conductor data, and a controller subsystem configured to compare input acceptance manufacturing criteria for a transparent conductor to stored reference transparent conductor data.
References
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Journal ArticleDOI
09 Jan 1998-Science
TL;DR: Studies carried out with different conditions and catalyst materials confirmed the central details of the growth mechanism and suggest that well-established phase diagrams can be used to predict rationally catalyst materials and growth conditions for the preparation of nanowires.
Abstract: A method combining laser ablation cluster formation and vapor-liquid-solid (VLS) growth was developed for the synthesis of semiconductor nanowires. In this process, laser ablation was used to prepare nanometer-diameter catalyst clusters that define the size of wires produced by VLS growth. This approach was used to prepare bulk quantities of uniform single-crystal silicon and germanium nanowires with diameters of 6 to 20 and 3 to 9 nanometers, respectively, and lengths ranging from 1 to 30 micrometers. Studies carried out with different conditions and catalyst materials confirmed the central details of the growth mechanism and suggest that well-established phase diagrams can be used to predict rationally catalyst materials and growth conditions for the preparation of nanowires.

4,405 citations

Journal ArticleDOI
TL;DR: In this paper, the thermaloxidation kinetics of silicon are examined in detail based on a simple model of oxidation which takes into account the reactions occurring at the two boundaries of the oxide layer as well as the diffusion process, the general relationship x02+Ax0=B(t+τ) is derived.
Abstract: The thermal‐oxidation kinetics of silicon are examined in detail. Based on a simple model of oxidation which takes into account the reactions occurring at the two boundaries of the oxide layer as well as the diffusion process, the general relationship x02+Ax0=B(t+τ) is derived. This relationship is shown to be in excellent agreement with oxidation data obtained over a wide range of temperature (700°–1300°C), partial pressure (0.1–1.0 atm) and oxide thickness (300–20 000 A) for both oxygen and water oxidants. The parameters A, B, and τ are shown to be related to the physico‐chemical constants of the oxidation reaction in the predicted manner. Such detailed analysis also leads to further information regarding the nature of the transported species as well as space‐charge effects on the initial phase of oxidation.

3,083 citations

Journal ArticleDOI
TL;DR: Highly sensitive, label-free, multiplexed electrical detection of cancer markers using silicon-nanowire field-effect devices in which distinct nanowires and surface receptors are incorporated into arrays opens up substantial possibilities for diagnosis and treatment of cancer and other complex diseases.
Abstract: We describe highly sensitive, label-free, multiplexed electrical detection of cancer markers using silicon-nanowire field-effect devices in which distinct nanowires and surface receptors are incorporated into arrays. Protein markers were routinely detected at femtomolar concentrations with high selectivity, and simultaneous incorporation of control nanowires enabled discrimination against false positives. Nanowire arrays allowed highly selective and sensitive multiplexed detection of prostate specific antigen (PSA), PSA-a1-antichymotrypsin, carcinoembryonic antigen and mucin-1, including detection to at least 0.9 pg/ml in undiluted serum samples. In addition, nucleic acid receptors enabled real-time assays of the binding, activity and small-molecule inhibition of telomerase using unamplified extracts from as few as ten tumor cells. The capability for multiplexed real-time monitoring of protein markers and telomerase activity with high sensitivity and selectivity in clinically relevant samples opens up substantial possibilities for diagnosis and treatment of cancer and other complex diseases.

2,396 citations

Journal ArticleDOI
25 Feb 2000-Science
TL;DR: Bulk quantities of defect-free silicon nanowires with nearly uniform diameters were grown to a length of several micrometers with a supercritical fluid solution-phase approach, and visible photoluminescence due to quantum confinement effects was observed, as were discrete optical transitions in the ultraviolet-visible absorbance spectra.
Abstract: Bulk quantities of defect-free silicon (Si) nanowires with nearly uniform diameters ranging from 40 to 50 angstroms were grown to a length of several micrometers with a supercritical fluid solution-phase approach. Alkanethiol-coated gold nanocrystals (25 angstroms in diameter) were used as uniform seeds to direct one-dimensional Si crystallization in a solvent heated and pressurized above its critical point. The orientation of the Si nanowires produced with this method could be controlled with reaction pressure. Visible photoluminescence due to quantum confinement effects was observed, as were discrete optical transitions in the ultraviolet-visible absorbance spectra.

1,535 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe the predictable synthesis of a broad range of binary and ternary III±V, II±VI, and IV±IV group semiconductor nanowires using the laser-assisted catalytic growth (LCG) method.
Abstract: The predictable synthesis of a broad range of multicomponent semiconductor nanowires has been accomplished using laser-assisted catalytic growth. Nanowires of binary group III±V materials (GaAs, GaP, InAs, and InP), ternary III±V materials (GaAs/P, InAs/P), binary II±VI compounds (ZnS, ZnSe, CdS, and CdSe), and binary SiGe alloys have been prepared in bulk quantities as high purity (>90 %) single crystals. The nanowires have diameters varying from three to tens of nanometers, and lengths extending to tens of micrometers. The synthesis of this wide range of technologically important semiconductor nanowires can be extended to many other materials and opens up significant opportunities in nanoscale science and technology. The synthesis of nanoscale materials is critical to work directed towards understanding fundamental properties of small structures, creating nanostructured materials, and developing nanotechnologies. Nanowires and nanotubes have been the focus of considerable attention because they have the potential to answer fundamental questions about one-dimensional systems and are expected to play a central role in applications ranging from molecular electronics to novel scanning microscopy probes. To explore such diverse and exciting opportunities requires nanowire materials for which the chemical composition and diameter can be varied. Over the past several years considerable effort has been placed on the bulk synthesis of nanowires, and while advances have been made using template, laser ablation, solution, and other methods, in no case has it been demonstrated that one approach could be exploited in a predictive manner to synthesize a wide range of nanowire materials. Here we describe the predictable synthesis of a broad range of binary and ternary III±V, II±VI, and IV±IV group semiconductor nanowires using the laser-assisted catalytic growth (LCG) method. Recently, we reported the growth of elemental Si and Ge nanowires using the LCG method, which exploits laser ablation to generate nanometer diameter catalytic clusters that define the size and direct the growth of the crystalline nanowires by a vapor±liquid±solid (VLS) mechanism. A key feature of the VLS growth process and our LCG method is that equilibrium phase diagrams can be used to predict catalysts and growth conditions, thereby enabling rational synthesis of new nanowire materials. Significantly, we show here that semiconductor nanowires of the III±V materials GaAs, GaP, GaAsP, InAs, InP, InAsP, the II±VI materials ZnS, ZnSe, CdS, CdSe, and IV±IV alloys of SiGe can be synthesized in high yield and purity using this approach. Compound semiconductors, such as GaAs and CdSe, are especially intriguing targets since their direct bandgaps give rise to attractive optical and electrooptical properties. The nanowires have been prepared as single crystals with diameters as small as 3 nm, which places them in a regime of strong radial quantum confinement, and lengths exceeding 10 mm. These studies demonstrate that LCG represents a very general and predictive approach for nanowire synthesis, and moreover, we believe that the broad range of III±V, II±VI, and IV±IV nanowires prepared will open up many new opportunities in nanoscale research and technology. The prediction of growth conditions for binary and more complex nanowires using the LCG method is, in principle, significantly more difficult than previous studies of elemental Si and Ge nanowires due to the complexity of ternary and higher order phase diagrams. However, this complexity can be greatly reduced by considering pseudobinary phase diagrams for the catalyst and compound semiconductor of interest. For example, the pseudobinary phase diagram of Au±GaAs shows that Au±Ga±As liquid and GaAs solid are the principle phases above 630 C in the GaAs rich region (Fig. 1). This implies that Au can serve as a catalyst to grow GaAs nanowires by the LCG method, if

1,429 citations