Free-standing aligned carbon nanotubes have previously been grown above 700°C on mesoporous silica embedded with iron nanoparticles. Here, carbon nanotubes aligned over areas up to several square centimeters were grown on nickel-coated glass below 666°C by plasma-enhanced hot filament chemical vapor deposition. Acetylene gas was used as the carbon source and ammonia gas was used as a catalyst and dilution gas. Nanotubes with controllable diameters from 20 to 400 nanometers and lengths from 0.1 to 50 micrometers were obtained. Using this method, large panels of aligned carbon nanotubes can be made under conditions that are suitable for device fabrication.

Patterned growth of freestanding carbon nanotube͑s͒ on submicron nickel dot͑s͒ on silicon has been achieved by plasma-enhanced-hot-filament-chemical-vapor deposition ͑PE-HF-CVD͒. A thin film nickel grid was fabricated on a silicon wafer by standard microlithographic techniques, and the PE-HF-CVD was done using acetylene (C 2 H 2 ) gas as the carbon source and ammonia (NH 3 ) as a catalyst and dilution gas. Well separated, single carbon nanotubes were observed to grow on the grid. The structures had rounded base diameters of approximately 150 nm, heights ranging from 0.1 to 5 m, and sharp pointed tips. Transmission electron microscopy cross-sectional image clearly showed that the structures are indeed hollow nanotubes. The diameter and height depend on the nickel dot size and growth time, respectively. This nanotube growth process is compatible with silicon integrated circuit processing. Using this method, devices requiring freestanding vertical carbon nanotube͑s͒ such as scanning probe microscopy, field emission flat panel displays, etc. can be fabricated without difficulty.

Highly-oriented, multi-walled carbon nanotubes were grown on polished polycrystalline and single crystal nickel substrates by plasma enhanced hot filament chemical vapor deposition at temperatures below 666°C. The carbon nanotubes range fiom 10 to 500 nm in diameter and 0.1 to 50 pm in length depending on growth conditions. Acetylene is used as the carbon source for the growth of the carbon nanotubes and ammonia is used for dilution gas and catalysis. The plasma intensity, acetylene to ammonia gas ratio and their flow rates, etc. affect the diameters and uniformity of the carbon nanotubes. [2]. Nanotube alignment is particularly important to enable both fundamental studies and applications, such as flat panel displays, vacuum microelectronics, chargeable batteries, etc. However, only one report exists on the growth of aligned carbon nanotubes by thermal decomposition of acetylene in nitrogen gas at temperature above 700°C on mesoporous silica containing iron nanoparticles [6] before our report on growth of large arrays of well-aligned carbon nanotubes on glass [16]. Here we report the growth of highly-oriented, multi-walled carbon nanotubes on nickel substrates at low temperatures by the same method (plasma enhanced hot tungsten-filament chemical vapor deposition) described in our previous paper [16]. The motivation to grow carbon nanotubes on Ni substrates is for the applications of using carbon nanotubes as battery electrodes and energy storage. We use acetylene (C2H2) to provide carbon for the growth of the carbon nanotubes and ammonia (NH3) gas for both dilution gas and catalysis. The catalytic role of ammonia is discussed in our previous paper [ 161.The base pressure of the deposition chamber is < 6 x Torr. We grew carbon nanotube films in a pressure of 1 -20 Torr maintained by flowing acetylene and ammonia gases with a total flow rate of 120 -200 sccm. We varied the acetylene-to-ammonia volume ratio fiom 1 : 2 to 1 : 10 for different experimental runs. Both polished polycrystalline and single-crystal Ni substrates were used. After stabilizing the working pressure, the tungsten filament coil powered by a DC source and the plasma-generator were turned on to generate heat and plasma. Under the present experimental set-up, the temperature of samples is estimated to be below 666 "c (which is the strain point of the display glass provided by Corning Inc.) since the display glass sit side by side with the Ni did not show any noticeable deformation after the experiments [ 161 and also Ni is not red-hot by visual observation. Growth durations were fiom 10 min to 5 h depending on the desired carbon nanotube lengths. Samples were examined by scanning electron microscopy (SEM, Hitachi S-4000) to measure tube lengths, diameters, site distributions, alignment, density and uniformity. High-resolution transmission electron microscopy (TEN was used to determine 2 the microstructure of individual tubes. Samples were also examined by x-ray diffraction, Raman spectroscopy, and x-ray photoemission spectroscopy to stud...

The development of devices suitable for heat management requires materials whose thermal properties and synthesis are well controlled.

The Coulomb hole reduces this repulsion and gives rise to a smaller net energy of the triplet. A£def(uCHF) and AE^rCHF) are very similar and much smaller than A£def(aiPI). In consequence, we obtain a smaller transition energy after correlation: 20.1-20.3 eV at the observed geometry.The correlation correction has reduced the aiPI error for this transition, at the observed geometry, from 14.8 to 2.72 eV. Moreover, the connection between the crystal and free-atom transition is much more sensible after inclusion of electron correlation (Figure 6): the crystal calculation at 11 bohr must be very close to the free-atom value, given the negligible neon-neon interactions at such distance. The residual error found in the rCHF spectral calculation may well be a measure of the shortcomings of our rigid model, defined in terms of a single-atom excitation taking place in an unrelaxed ground-state lattice.According to this work, the *S -* 3P transition energy increases with pressure up to 60 GPa. A similar result was found by LeSar for solid argon.10 VI. ConclusionsWe have shown that the ab initio perturbed ion method, initially designed to study ionic systems,12•13,17 can describe simple van der Waals systems such as solid neon. The pseudoatomic character of the aiPI method suggests a simple and intuitive analysis of the lattice stabilization, showing the relative importance of different orbitals and different terms in the Hamiltonian. The aiPI method can also be a very useful tool as generator of (a) atomic wave functions consistent with its lattice environment, and (b) local effective potentials for different atoms in the lattice. This information may be a sensible input for more involved molecularcluster calculations.The following conclusions can be drawn from our calculation:1. The aiPI method predicts the binding energy and the equilibrium lattice parameter of fee neon in agreement with experimental information.2. For small lattice sizes the crystal electron density is contracted with respect to the gas-phase density. This effect is mostly due to the 2p atomic orbital, the Is and 2s orbitals playing a negligible role.3. The crystal stabilization may be understood in terms of two pure quantum-mechanical effects: the long-range, attractive exchange interaction and the short-range lattice-projection energy representing the atom-lattice orthogonality.4. It appears that the Is and 2s electron densities act as stabilizing factors whereas the 2p density slightly destabilizes the crystal.5. The 2p -3s instantaneous absorption has been studiedwithin the aiPI method in terms of an excited atom embedded in the ground-state crystal. A new interpretation is given for the energy shift with respect to the gas-phase absorption, in terms of deformation and interaction energies of the two states involved in the transition. The analysis reveals the importance of electron correlation effects in the excited state, originating from the large crystal-induced compression of the 3s state. This transition seems to increase with increasing ext...

Ti is introduced as a dopant during the atomic layer deposition (ALD) growth of ZnO for use as a transparent electrode. ALD-grown Ti-doped ZnO (TZO) films are deposited via alternate stacking of ZnO and TiO x atomicdoping layers. Their growth behavior, structural, electrical and optical properties are investigated.Macroscopic film growth and doping concentration characterization show that both diethylzinc and titanium tetrakis(isopropoxide) exhibit enhanced adsorption during the ALD of TZO films. Contrary to conventional homogeneous compounds, atomic-layer Ti doping by ALD results in a much higher electrical conductivity and doping efficiency compared to its Al counterpart. Specifically, the ALD-grown TZO films show an electrical conductivity of 951 S cm À1 , nearly twice that of AZO films (591 S cm À1 ), thanks to the high doping efficiency of Ti (41%) and its extraordinary high mobility (>20 cm 2 V À1 s À1 ). Such high electron mobility is likely due to a smaller concentration of inactivated dopants as scattering centers.

Ultrasmooth and highly conductive amorphous In−Zn−O (a-IZO) films are grown by atomic layer deposition (ALD). This opens a new pathway to highly transparent and conductive oxides with an extreme conformality. In this process, a-IZO films of various compositions are deposited by alternate stacking of ZnO and In 2 O 3 atomic-layers at a temperature of 200°C. The IZO films have an amorphous phase over a wide composition range, 43.2−91.5 at %, of In cation ratio. The In-rich a-IZO film (83.2 at % In) exhibits a very low resistivity of 3.9 × 10 −4 Ω cm and extremely high electron mobility in excess of 50 cm 2 V −1 s −1 , one of the highest among the reported ALD-grown transparent conducting oxides. Moreover, it exhibits an ultrasmooth surface (∼0.2 nm in root-mean-square roughness), and can be conformally coated onto nanotrench structures (inlet size: 25 nm) with excellent step coverage of 96%.

The temperature coeffi cient of resistance of a carbon nanotube nanocomposite with the non-conductive phase-change hydrogel Poly(N-isopropylacrylamide) is studied. This nanocomposite is found to achieve the largest reported temperature coeffi cient of resistance, ≈ − 10%/ ° C, observed in carbon nanotube-polymer nanocomposites to date. The giant temperature coefficients of resistance results from a volume-phase-transition that is induced by the humidity present in the surrounding atmosphere and that enhances the temperature dependence of the resistivity via direct changes in the tunneling resistance that electrons experience in moving between nearby carbon nanotubes. The bolometric photoresponses of this new material are also studied. The nanocomposite's enhanced responses to temperature and humidity give it great potential for sensor applications and uncooled infrared detection.