Fabrication and characterization of single electron tunneling device on Au/SiO2 nanocomposite films

Amino-functionalized mesoporous silica thin films (AF-MSTFs) have been directly dip-coated on silica wafers by co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) in the presence of Brij56 (C16H33(OCH2CH2)10OH) under acidic condition. Using the AF-MSTFs as templates, gold nanoparticles (GNPs) are well formed within the mesopores. The transmission electron microscope images and X-ray diffraction patterns demonstrate that the MSTFs are consistent with well ordered mesostructures and the GNPs are well crystallized in the templates. A single electron tunneling device based on self-assembled GNPs of the Au/SiO2 nanocomposite film has been fabricated by using nanolithographic definitions. The device shows Coulomb stair-cases at 77 K. The data are interpreted as single electron tunneling through the GNP which served as a Coulomb island between the source and drain electrodes. The charging energy is estimated to be much larger than the thermal energy at 77 K. The Coulomb island size calculated from the experimental data is -3.8 nm, which is consistent with the size of the GNPs self-assembled in the MSTFs.