Dresden 2011 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 48: ZnO: Devices

HL 48.4: Talk

Wednesday, March 16, 2011, 11:00–11:15, POT 151

Covalent functionalization of ZnO nanowires — •Andreia da Rosa, Ney Moreira, and Thomas Frauenheim — BCCMS, University of Bremen, Am Fallturm 1, 28359, Bremen, Germany

Understanding the interaction of organic species with inorganic nanostructures constitutes a step forward in the development of semiconductor based biosensors. In this work we have used density functional theory to investigate ZnO-(1010) nanowire surfaces modified with substituted methane molecules (Me-X, with X= OH, NH2, SH, COOH, and CN). We have found three relevant mechanisms for surface stabilization: passivation of surface oxygen lone-pairs via dissociative chemisorption processes, electrostatic adsorbate-interations involving Zn surface sites and hydrogen bonding interactions involving oxygen surface sites. Covalent adsorbate-substrate interactions were found to play only a marginal role on the surface stabilization. Contradicting the usual chemical intuition, we have found no significant evidence for the formation of classical Lewis acid-base adducts on Zn surface sites. Finally we suggest that the functionalization with Me-COOH is also expected to be stable under ordinary laboratory conditions or in aqueous media.