Abstract: Gas sensors are provided. The gas sensors include a gas sensing element having metal oxide nanoparticles and a thin-film heating element. Systems that include the gas sensors, as well as methods of using the gas sensors, are also provided. Embodiments of the present disclosure find use in a variety of different applications, including detecting whether an analyte is present in a gaseous sample.

Abstract: A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

Abstract: Methods by which the growth of a nanostructure may be precisely controlled by an electrical current are described here. In one embodiment, an interior nanostructure is grown to a predetermined geometry inside another nanostructure, which serves as a reaction chamber. The growth is effected by a catalytic agent loaded with feedstock for the interior nanostructure. Another embodiment allows a preexisting marginal quality nanostructure to be zone refined into a higher-quality nanostructure by driving a catalytic agent down a controlled length of the nanostructure with an electric current. In both embodiments, the speed of nanostructure formation is adjustable, and the growth may be stopped and restarted at will. The catalytic agent may be doped or undoped to produce semiconductor effects, and the bead may be removed via acid etching.

Abstract: A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

Abstract: A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

Abstract: Methods by which the growth of a nanostructure may be precisely controlled by an electrical current are described here. In one embodiment, an interior nanostructure is grown to a predetermined geometry inside another nanostructure, which serves as a reaction chamber. The growth is effected by a catalytic agent loaded with feedstock for the interior nanostructure. Another embodiment allows a preexisting marginal quality nanostructure to be zone refined into a higher-quality nanostructure by driving a catalytic agent down a controlled length of the nanostructure with an electric current. In both embodiments, the speed of nanostructure formation is adjustable, and the growth may be stopped and restarted at will. The catalytic agent may be doped or undoped to produce semiconductor effects, and the bead may be removed via acid etching.

Abstract: A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

Abstract: A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

Abstract: The invention relates to a method for forming a telescoped multiwall nanotube. Such a telescoped multiwall nanotube may find use as a linear or rotational bearing in microelectromechanical systems or may find use as a constant force nanospring. In the method of the invention, a multiwall nanotube is affixed to a solid, conducting substrate at one end. The tip of the free end of the multiwall nanotube is then removed, revealing the intact end of the inner wall. A nanomanipulator is then attached to the intact end, and the intact, core segments of the multiwall nanotube are partially extracted, thereby telescoping out a segment of nanotube.

Abstract: A solid phase or form of carbon is based on fullerenes with thirty six carbon atoms (C36). The C36 structure with D6h symmetry is one of the two most energetically favorable, and is conducive to forming a periodic system. The lowest energy crystal is a highly bonded network of hexagonal planes of C36 subunits with AB stacking. The C36 solid is not a purely van der Waals solid, but has covalent-like bonding, leading to a solid with enhanced structural rigidity. The solid C36 material is made by synthesizing and selecting out C36 fullerenes in relatively large quantities. A C36 rich fullerene soot is produced in a helium environment arc discharge chamber by operating at an optimum helium pressure (400 torr). The C36 is separated from the soot by a two step process. The soot is first treated with a first solvent, e.g. toluene, to remove the higher order fullerenes but leave the C36. The soot is then treated with a second solvent, e.g.

Abstract: The invention relates to a method for forming a telescoped multiwall nanotube. Such a telescoped multiwall nanotube may find use as a linear or rotational bearing in microelectromechanical systems or may find use as a constant force nanospring. In the method of the invention, a multiwall nanotube is affixed to a solid, conducting substrate at one end. The tip of the free end of the multiwall nanotube is then removed, revealing the intact end of the inner wall. A nanomanipulator is then attached to the intact end, and the intact, core segments of the multiwall nanotube are partially extracted, thereby telescoping out a segment of nanotube.

Abstract: The invention relates to a method for shaping small three-dimensional articles such as nanotube exhibiting a layered structure through material removal such that the article is controllably shaped to exhibit a desired contour. Typically, material removal does not require use of a chemical etchant and is carried out while the article and a shaping electrode are positioned in contact material removal relationship with under a potential difference. The invention also relates to nanotubes and small three-dimensional articles exhibiting a layered structure having a controllably shaped contour.

Abstract: The invention relates to a method for shaping small three-dimensional articles such as nanotube exhibiting a layered structure through material removal such that the article is controllably shaped to exhibit a desired contour. Typically, material removal does not require use of a chemical etchant and is carried out while the article and a shaping electrode are positioned in contact material removal relationship with under a potential difference. The invention also relates to nanotubes and small three-dimensional articles exhibiting a layered structure having a controllably shaped contour.

Abstract: By a simple method single suspended carbon nanotubes (CNTs) are deposited at predetermined locations on a pre-patterned device. A narrow trench is first formed on the device at the desired location for depositing a CNT. A fluid drying deposition process is then used to mount the CNT at the chosen location. A droplet of a solvent containing the CNTs in suspension is deposited at the desired location, and the solvent is allowed to evaporate. This leaves the CNT bridging the trench at the selected location. The effect is enhanced by applying an electric field. The method is also applicable to other nano-elongated objects such as nanowires and biomolecules.

Abstract: The invention relates to a method for forming a telescoped multiwall nanotube. Such a telescoped multiwall nanotube may find use as a linear or rotational bearing in microelectromechanical systems or may find use as a constant force nanospring. In the method of the invention, a multiwall nanotube is affixed to a solid, conducting substrate at one end. The tip of the free end of the multiwall nanotube is then removed, revealing the intact end of the inner wall. A nanomanipulator is then attached to the intact end, and the intact, core segments of the multiwall nanotube are partially extracted, thereby telescoping out a segment of nanotube.

Abstract: The invention relates to a method for shaping small three-dimensional articles such as nanotube exhibiting a layered structure through material removal such that the article is controllably shaped to exhibit a desired contour. Typically, material removal does not require use of a chemical etchant and is carried out while the article and a shaping electrode are positioned in contact material removal relationship with under a potential difference. The invention also relates to nanotubes and small three-dimensional articles exhibiting a layered structure having a controllably shaped contour.