Parts | Days | Selection | Search | Downloads | Help

SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications

SYSA 5: Poster Session SYSA

SYSA 5.51: Poster

Tuesday, February 26, 2008, 14:30–20:00, Poster A

Chemical modification of GaAs surfaces with novel functional peptides — •Thomas Kaindl¹, Klaus Adlkofer¹, Tomoyuki Morita², Shunsaku Kimura², Michael Himmelhaus¹, and Motomu Tanaka¹ — ¹Physikalisch Chemisches Institut, INF 253, 69120 Heidelberg, Universität Heidelberg — ²Department of Material Chemistry, Kyoto University Nishikyo-ku, 615-8510 Kyoto, Japan

The interconnection of biological molecules (peptides, enzymes, etc.) with solid based devices offers great advantages towards the creation of new functional hybrid materials. Molecular dipole engineering was achieved by deposition of helical peptides, carrying a large dipole moment, onto GaAs [100] surfaces. After optimization of the preparation protocols the formed monolayers were systematically studied by various surface sensitive methods. Ellipsometric film thickness measurements and topographic studies by AFM revealed a macroscopically uniform monolayer formation with few surface defects. The averaged tilt angle of the peptide helix axis was estimated by TM-FTIR, where all peptides showed nearly vertical orientation on the GaAs. To gain further information of the molecular level structure, radiation impeding grazing-incidence x-ray scattering out of specular plane experiments were carried out. The same functionalization protocol was successfully adapted to commercially available, high electron mobility transistors. Based on the preceding thorough structural characterization of the peptide layers on bulk GaAs, a significant influence of the molecular dipole moments on the transistors characteristics could be demonstrated.