Bias Induced Transition from an Ohmic to a Non-Ohmic Interface in Supramolecular Tunneling Junctions with Ga2O3/EGaIn Top Electrodes

Wimbush, Kim S. ; Fratila, Raluca M. (Universidad de Zaragoza) ; Wang, Dandan ; Qi, Dongchen ; Liang, Cao ; Yuan, Li ; Yakovlev, Nikolai ; Loh, Kian Ping ; Reinhoudt, David N. ; Velders, Aldrik H. ; Nijhuis, Christian A.

Resumen: This study describes that the current rectification ratio, R = |J|(-2.0 V)/|J|(+2.0 V) for supramolecular tunneling junctions with a top-electrode of eutectic gallium indium (EGaIn) that contains a conductive thin (0.7 nm) supporting outer oxide layer (Ga2O3), increases by up to four orders of magnitude under an applied bias of >+1.0 V up to +2.5 V; these junctions did not change their electrical characteristics when biased in the voltage range of ±1.0 V. The increase in R is caused by the presence of water and ions in the supramolecular assemblies which react with the Ga2O3/EGaIn layer and increase the thickness of the Ga2O3 layer. This increase in the oxide thickness from 0.7 nm to ~2.0 nm changed the nature of the monolayer–top-electrode contact from an ohmic to a non-ohmic contact. These results unambiguously expose the experimental conditions that allow for a safe bias window of ±1.0 V (the range of biases studies of charge transport using this technique are normally conducted) to investigate molecular effects in molecular electronic junctions with Ga2O3/EGaIn top-electrodes where electrochemical reactions are not significant. Our findings also show that the interpretation of data in studies involving applied biases of >1.0 V may be complicated by electrochemical side reactions which can be recognized by changes of the electrical characteristics as a function voltage cycling or in current retention experiments.

Idioma: Inglés

DOI: 10.1039/C4NR02933J

Año: 2014

Publicado en: NANOSCALE 6, 19 (2014), 11246-58
ISSN: 2040-3364

Factor impacto JCR: 7.394 (2014)

Categ. JCR: MATERIALS SCIENCE, MULTIDISCIPLINARY rank: 21 / 260 = 0.081 (2014) - Q1 - T1
Categ. JCR: NANOSCIENCE & NANOTECHNOLOGY rank: 10 / 80 = 0.125 (2014) - Q1 - T1
Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 19 / 157 = 0.121 (2014) - Q1 - T1
Categ. JCR: PHYSICS, APPLIED rank: 12 / 144 = 0.083 (2014) - Q1 - T1

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Química Orgánica (Dpto. Química Orgánica)