Control of junction resistances in molecular electronic devices fabricated by FIB

• A major hurdle to realize molecular electronic devices (MEDs) is to make reliable electrical contacts to a single or a few molecules. Our nano-contact platform with a gap size of less than 25 nm with resistances above 1000 TΩ was built using combined techniques of photolithography, electron beam lithography and focused ion beam milling. In this study, we have used gold nanoparticles (AuNPs) to bridge the nanoelectrode gaps by dielectrophoretic trapping and thus obtain electrical contacts. The electrodes and/or the nanoparticles were functionalised with 1–2 nm long alkane-thiol molecules so that the electronic structure of these molecules determines the properties of the electrical junction. Molecules were introduced both by functionalising the nanogap and the nanoparticles and the results of both functionalisation protocols are compared. Here, we show the nanogap–nanoparticle bridge set-up containing metal–molecule junctions that can be used as a base for the development of molecular electronics containing only a few molecules under ambient conditions. Current–voltage (I–V) characterization of alkanethiol/gold junction showed non-linear response where mean geometric resistance of four different junctions could be tuned from 20 GΩ to 20 TΩ. The results from the measurements on 1-alkanethiol in such devices is a first step to demonstrate that this platform has the potential to obtain stable electronic devices having relatively small numbers of molecules with reliable metal molecule junction by combing top-down and bottom-up approaches.

Nyckelord

Nanoelectrodes

Nanogap-nanoparticle bridge set-up

Molecular electronics

Metal-moleculejunctions

1-alkanethiol

Electrical characterizatio

Teknisk fysik med inriktning mot materialvetenskap

Engineering Science with specialization in Materials Science

Teknisk fysik med inriktning mot nanoteknologi och funktionella material

Engineering Science with specialization in Nanotechnology and Functional Materials

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)