No abstract

No abstract

By applying a dithiol (1,6-hexanedithiol) treatment, it was observed that a submonolayer of gold colloidal particles deposited by using an aminosilane adhesion agent [i.e., 3-(2-aminoethylamino) propyltrimethoxysilane] transform themselves into chains consisting of a few gold colloidal particles. In those chains, gold colloidal particles are believed to be linked by alkane chains derived from the dithiol molecules. The particle chain was formed on a SiO2 substrate with source, drain, and gate metal electrodes defined by electron beam lithography. It was observed that the gold particle chain bridged a gap between the source and drain forming a single electron transistor with a multi-tunnel junction in the particle chain. The electron conduction through the chain exhibited a clear Coulomb staircase and the periodic conductance oscillation as a function of gate voltage. These measurement results corresponded closely to the results of a simulation based on the orthodox theory.

The ability to grow carbon nanotubes/nanofibres (CNs) with a high degree of uniformity is desirable in many applications. In this paper, the structural uniformity of CNs produced by plasma enhanced chemical vapour deposition is evaluated for field emission applications. When single isolated CNs were deposited using this technology, the structures exhibited remarkable uniformity in terms of diameter and height (standard deviations were 4.1 and 6.3% respectively of the average diameter and height). The lithographic conditions to achieve a high yield of single CNs are also discussed. Using the height and diameter uniformity statistics, we show that it is indeed possible to accurately predict the average field enhancement factor and the distribution of enhancement factors of the structures, which was confirmed by electrical emission measurements on individual CNs in an array.

The present limit of around 10 nm for the width of lines fabricated by e-beam lithography using polymethylmethacrylate (PMMA) resist on silicon substrates has been overcome. 5–7 nm wide etched lines in bulk Si substrates have been produced. A 65 nm thick layer of PMMA was exposed with an 80 kV electron beam of diameter smaller than 5 nm. After exposure the resist was developed in 3:7 cellosolve:methanol with ultrasonic agitation. The pattern in resist was transferred to the Si substrate with reactive ion etching. Lines of width varying between 5 and 7 nm were recorded using an S-900 scanning electron microscope which has a resolution of 0.7 nm.