Molecular rectifying diodes from self-assembly on silicon

We demonstrate a molecular rectifying junction made from a sequential self-assembly on silicon. The device structure consists of only one conjugated (a) group and an alkyl spacer chain. We obtain rectification ratios up to 37 and threshold voltages for rectification between -0.3 and -0.9 V. We show that rectification occurs from resonance through the highest occupied molecular orbital of the pi group in good agreement with our calculations and internal photoemission spectroscopy. This approach allows us to fabricate molecular rectifying diodes compatible with silicon nanotechnologies; for future hybrid circuitries.