MOLECULAR ELECTRONIC TUNING OF SI SURFACES

Assembling quinolinium-based chromophores on silicon surfaces provides a new route to electronic control over such semiconducting surfaces. The two-step process by which the molecules are grafted on to the surf ace involves first coupling the organic functionality to silicon, foll owed by chromophore anchoring. These synthetic steps are monitored by XPS, UV-Vis and FTIR spectroscopies. Using contact potential differenc e measurements we found that the electron affinity of the modified sil icon is a function of the molecule's dipole moment. The same technique shows a pronounced effect of the sub-nanometer siloxane-based, coupli ng-agent, layer by itself on the band bending and band-bending modific ation as function of chromophore adsorption. (C) 1997 Published by Els evier Science B.V.