Controlled alignment of catalytically grown carbon nanofibers ͑CNFs͒ at a variable angle to the substrate during a plasma-enhanced chemical vapor deposition process is achieved. The CNF alignment is controlled by the direction of the electric field lines during the synthesis process. Off normal CNF orientations are achieved by positioning the sample in the vicinity of geometrical features of the sample holder, where bending of the electric field lines occurs. The controlled growth of kinked CNFs that consist of two parts aligned at different angles to the substrate normal also is demonstrated.

A concept for maskless digital electrostatically focused e-beam array direct-write lithography (DEAL) has been developed at Oak Ridge National Laboratory. This concept incorporates a digitally addressable field-emission array (DAFEA) integrated into a logic and control circuit implemented as an integrated circuit. The design goal is for 3 000 000 individually addressable field-emission cathodes with a 4 μm by 8 μm pitch on a single ∼1 cm2 integrated circuit. The DAFEA design includes built-in electrostatic focusing for each emitter with feedback dose-control circuits to drive each emitter for tightly controlled electron delivery. With the electrostatic focusing, an array of ∼460 of these integrated circuits (up to 30 across by ∼23 rows deep) are suspended on a back plane ∼100 μm above a 300 mm semiconductor wafer. This arrangement could lithographically expose an entire 300 mm wafer, with 30 nm pixels, in less than 45 s, with every wafer pixel redundantly illuminated eight times allowing gray-scale edge placement. Only ∼1.5 cm of wafer motion is required for complete wafer exposure. High-speed data paths are proposed to program the patterns into the DAFEA to be written to the wafer. The DEAL concept thus requires no mask and can be extended to the 10 nm linewidth regime.

2319timized while taken alone. Will this result remain valid to all orders? While a formal analysis proves to be rather difficult, a numerical test is possible for both liquid He and the charged Bose gas. One could first carry out a paired-phonon analysis using the Jastrow function alone, and then study the effect of including three-particle factors such as that in Eq. (79). The energy thus obtained is expected to be logvsr than that obtained in (ii).

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Field emission from isolated individual vertically aligned carbon nanocones ͑VACNCs͒ has been measured using a small-diameter moveable probe. The probe was scanned parallel to the sample plane to locate the VACNCs, and perpendicular to the sample plane to measure the emission turn-on electric field of each VACNC. Individual VACNCs can be good field emitters. The emission threshold field depends on the geometric aspect ratio ͑height/tip radius͒ of the VACNC and is lowest when a sharp tip is present. VACNCs exposed to a reactive ion etch process demonstrate a lowered emission threshold field while maintaining a similar aspect ratio. Individual VACNCs can have low emission thresholds, carry high current densities, and have long emission lifetime. This makes them very promising for various field emission applications for which deterministic placement of the emitter with submicron accuracy is needed.