Dependency of the Tunneling Decay Coefficient in Molecular Tunneling Junctions on the Topography of the Bottom Electrodes

Abstract

AbstractA controversy in molecular electronics is the unexplained large spread in values of the tunneling decay coefficient β in tunneling junctions with self‐assembled monolayers of n‐alkanethiolates (SCn). We show control of the β value over the range 0.4–1.0 nC−1 in junctions by changing the topography of the bottom electrodes that support the SAMs. Very low β values (0.4–0.5 nC−1) are obtained for rough surfaces with large areas of exposed grain boundaries, while β=1.0 nC−1 for smooth surfaces with small areas of exposed grain boundaries.