Temperature-dependent current–voltage measurements of Au/C9H7N/p-Si: Characterization of a metal–organic-semiconductor device

Abstract

The attachment of organic molecules onto the silicon surfaces is of crucial interest for the development of nanoscale organic–inorganic hybrid materials. In this study, the electrografting of diazonium salts has been used for covalent attachment of the molecules to H-passivated silicon (100) surface. The modification of silicon electrodes with quinoline molecules was carried out through electrochemical reduction of in situ generated diazonium salts from 6-aminoquinoline, and thus an Au/quinoline/p-Si device was fabricated. The results measured from the as-deposited device displayed a higher barrier height at room temperature due to the formation of an interfacial dipole at a metal/organic interface during electrochemical deposition. It has been shown that the barrier height value was increased with the increasing temperature. In addition, there were seen two different behaviours of the temperature-dependent ideality factor and this was attributed to the response of quinoline to temperature below and above 160K such it is likely to take place phase change at the interface. Such a temperature dependence of the barrier height was explained by the Gaussian distribution of the barrier heights due to the barrier height inhomogeneities at the quinoline film/p-type silicon interface. The mean barrier height and the standard deviation σ values were determined as 0.87eV and 0.0989V, respectively. Furthermore, the Norde model was also used for determining the temperature-dependent of barrier height and it was seen that there was a good agreement between that of the common ln(I)–V and Norde model.