Mass-fabricated one-dimensional silicon nanogaps for hybrid organic/nanoparticle arrays

Abstract

Optical lithography based on microfabrication techniques was employed to fabricate one-dimensional nanogaps with micrometre edge lengths in silicon. These one-dimensional nanogaps served as a platform on which organic/nanoparticle films were assembled. Characterization of the gaps was performed with high-resolution TEM, SEM, and electrical measurements. Novel self-assembling attachment chemistry, based on the interaction of silicon with a diazonium salt, was used to iteratively build a multi-layer nanoparticle film across a 7 nm gap. By using nanoparticles capped with an easily displaced ligand, a variable conductive path was created across the 1D nanogap. Electrical measurements of the gap showed a dramatic change in the I(V) characteristics after assembly of the nanoparticle film.

Nanogap Electrodes

“…This high-aspect-ratio configuration was potentially suitable for averaging molecular conductance measurements, provided the target molecules were in www.advmat.de a desired distribution without interacting. Silicon nanogaps [116][117][118] for connection of organic molecules into standard silicon technology (CMOS) have also been exploited by selectively etching the intermediate layer of silicon dioxide. There is one thing that needs to be noted after the molecular or atomic templates are removed, i.e., the final gap is unlikely to be the exact size of the ruler element due to a relaxation effect of the metal structures.…”

In Situ Stepwise Synthesis of Functional Multijunction Molecular Wires on Gold Electrodes and Gold Nanoparticles

“…Interest in molecular electronics has focused on materials that act as diodes [1,2] or wires, [3][4][5] and on the development of innovative techniques for contacting to single molecules and ultrathin films. [6][7][8][9][10][11][12][13][14] They include, for example, the in situ synthesis of molecular wires on solid supports, [10][11][12][13][14] in which recent advances have resulted in the bridging of nanometersized gaps between electrodes by the coupling of aminoterminated molecules between opposing surface-based aldehyde groups on the electrode coatings. [12][13][14] For photovoltaic applications, molecules may be elongated in situ on nanoparticles with differently colored linked units to provide charge-transport pathways along the conjugated wirelike backbones.…”

Advantages of Prefabricated Tunnel Junction-Based Molecular Spintronics Devices

“…34 The TJMD's insulating spacer also serves as a robust di®usion barrier and hence minimizes the failure due to the di®usion of metal atoms via spacer. 25 A TJMD is also quite forgiving toward the quality of molecular self-assembly between the two metal electrodes. 34 Since molecules of interest always stay on edges [ Fig.…”

“…1(b)], 5,[16][17][18] (iii) molecule placed in a nanoscale gap of a metal planar nanogap junction [ Fig. 1(c)], [19][20][21] (iv) molecules chemically bonded to the two metal¯lms of a tunnel junction along the exposed edges 3,[22][23][24][25] ; this approach utilizes a vertical edge of thin¯lm 26,27 [Figs. 1(d)-1(e)].…”