Strong interaction of gold with the terminal sulfur atoms of dithiol molecules on Au(111) effectively suppresses the penetration of deposited Au atoms through the dithiol layer and results in the formation of homogeneous Au nanoclusters. These nanoclusters, 10–15 Å (σ<2 Å) in height, spread over the surface with a density of ∼1.2×1013/cm2 for coverage between 0.25–2.5 monolayers. Decoupling of the clusters from Au(111) by the octanedithiol layer (∼12 Å in thickness) and the small self-capacitance of these nanoparticles (10−19–10−18 F) make it possible to observe both the Coulomb blockade in scanning tunneling spectroscopy and the Au 4f core level shifts in x-ray photoelectron spectroscopy at room temperature. Both phenomena can be attributed to a common physical origin—e2/2C—the Coulomb energy of charged particles.

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The shot noise characteristics of a resonant tunnelling diode are calculated from the model which includes the effects of the effective transmission coefficient of electrons in the conduction band and in the subband of the accumulation layer in the emitter. The transit time is formulated for a double barrier structure. However, the transit time for electrons at the Fermi level and the subband of the emitter are different because of the energy difference. The results show that the shot noise spectrum is independent of the frequency at low and intermediate frequencies and dependent on the frequency at high frequencies.

A novel ultrahigh vacuum system for the fabrication and measurement of nanostructures has been developed, which consists of a preparation chamber, a precise mask deposition facility, a scanning tunneling microscope (STM) for nanofabrication, and a low temperature four-contact-probe apparatus. Using the field-induced atom transfer from a gold STM tip, it has been demonstrated that nanometer-scale gold structures can be fabricated not only on an atomically clean - surface but also in a gap region among four macroscopic electrodes on a sputter-cleaned Si(111) surface. The overall findings clearly suggest that the STM atom-transfer technique has proved itself to be a very promising candidate for fabricating nanometer-scale single electron devices.