Probe-based measurement of lateral single-electron transfer between individual molecules.

Wolfram Steurer,Gerhard Meyer,Leo Gross,Shadi Fatayer

doi:10.1038/ncomms9353

Abstract

The field of molecular electronics aims at using single molecules as functional building blocks for electronics components, such as switches, rectifiers or transistors. A key challenge is to perform measurements with atomistic control over the alignment of the molecule and its contacting electrodes. Here we use atomic force microscopy to examine charge transfer between weakly coupled pentacene molecules on insulating films with single-electron sensitivity and control over the atomistic details. We show that, in addition to the imaging capability, the probe tip can be used to control the charge state of individual molecules and to detect charge transfers to/from the tip, as well as between individual molecules. Our approach represents a novel route for molecular charge transfer studies with a host of opportunities, especially in combination with single atom/molecule manipulation and nanopatterning techniques.

Highlights

The field of molecular electronics aims at using single molecules as functional building blocks for electronics components, such as switches, rectifiers or transistors
Owing to the high sensitivity of the atomic force microscope (AFM), intermolecular charge transfer can be measured with single-electron sensitivity[12,13,14], and charge state detection is possible at large tip-molecule separations
Pentacene adsorbed on bilayer NaCl films has been intensively studied by STM16,17 and AFM18, and is readily identified via high-resolution AFM images obtained with pentacene-decorated tips[18]

Summary

Introduction

The field of molecular electronics aims at using single molecules as functional building blocks for electronics components, such as switches, rectifiers or transistors. We use atomic force microscopy to examine charge transfer between weakly coupled pentacene molecules on insulating films with single-electron sensitivity and control over the atomistic details. Our approach represents a novel route for molecular charge transfer studies with a host of opportunities, especially in combination with single atom/molecule manipulation and nanopatterning techniques. Single molecules and molecular assemblies are arranged on a bulk-like insulating film, and the tip of an atomic force microscope (AFM) is used to control and detect their charge state. Owing to the high sensitivity of the AFM, intermolecular charge transfer can be measured with single-electron sensitivity[12,13,14], and charge state detection is possible at large tip-molecule separations. The combination of our method with atom/molecule manipulation[15] and top-down nanopatterning techniques might open up the prospect of studying atomically defined molecular junctions in the future

Methods

Results

Conclusion