Fabrication of quantum dots using multicoated self-assembled monolayer

Abstract

Novel cyanoterphenyl self-assembly monolayers on Au(111) studied by ellipsometry, x-ray photoelectron spectroscopy, and vibrational spectroscopies J. Chem. Phys. 122, 224707 (2005); 10.1063/1.1893618 Self-assembled monolayer cleaning methods: Towards fabrication of clean high-temperature superconductor nanostructures Appl. Phys. Lett. 86, 154104 (2005); 10.1063/1.1899753Patterning of gold film on muscovite mica by using a helium-metastable atom beam and an octanethiol selfassembled monolayerThe authors have fabricated quantum dots with various nanogaps by controlling the number of self-assembled molecular coatings. First, Au electrodes with a unique shape were obtained using conventional lithography. Then, a self-assembled multilayer, composed of alternating layers of 16-mercaptoalkanoic acids ͓HS͑CH 2 ͒ 15 COOH, 16-MHDA͔ and copper ͑II͒ ions, were deposited on Au electrode patterns to form the controllable gap between adjacent Au electrodes. After reaching a nanometer-scale gap, the second Au was deposited again using e-beam evaporation. Finally, both the second Au and molecular resist were removed by lift-off, thereby resulting in quantum dots with a nanogap between gold electrodes. Ellipsometry and cyclic voltammetry were used to find the number of self-assembled molecular layers. In addition, contact angle and x-ray photoelectron spectroscopy were used to analyze chemical properties between gold and the self-assembled multilayer. Field-emission scanning-electron microscopy was used for characterization of shapes of nanogaps and quantum dots.