Electrical bistability in electrografted 5-(4-undecenyloxyphenyl)-10,15,20-triphenylporphyrin monolayer on Si

For futuristic hybrid nanoelectronics it is essential that functional organic molecules should be grafted to Si. For this purpose, we have synthesized a specifically designed organic molecule, that is, 5-(4-undecenyloxyphenyl)-10,15,20-triphenylporphyrin (TPP-C11), and these molecules were electrografted on highly doped n-Si substrates. TPP-C11 molecules exhibited a hysteresis in current–voltage (J–V) characteristics, with a sharp jump in current at a bias of ±0.6 V. We propose that the J–V hysteresis could be associated with the resonant tunneling through HOMO/LUMO of the porphyrin moiety. We also demonstrate that such electrical bistability can be utilized for the molecular memory effect.