Room-temperature single-electron transistors using alkanedithiols

We have fabricated single-electron transistors by alkanedithiol molecular self-assembly. The devices consist of spontaneously formed ultrasmall Au nanoparticles linked by alkanedithiols to nanometer-spaced Au electrodes created by electromigration. The devices reproducibly exhibit addition energies of a few hundred meV, which enables the observation of single-electron tunneling at room temperature. At low temperatures, tunneling through discrete energy levels in the Au nanoparticles is observed, which is accompanied by the excitations of molecular vibrations at large bias voltage.