EAPSI: Characterization and molecular modification of semiconductor nano-devices

Keiper Timothy, Tallahassee FL

Investigators

Abstract

Semiconductors are playing an interesting role in the development of new medical technologies. Design of nano-devices capable of real-time, on-site medical diagnostics for the improvement of patient care requires understanding of the synthesis, physical properties and effects of molecular modification of the surface of these materials, which change characteristics in specific environments. These so-called field effect transistors (FETs) respond to the electric field or electric charge of surface-bound species. Putting molecules on the surface may increase the FET's performance while specific functionalization of the surface for desired biomolecules is required for medical implications. This research will be conducted in collaboration with Dr. Jianhua Zhao at the Institute of Semiconductors, Chinese Academy of Sciences. Dr. Zhao's expertise in growth and characterization of nanostructures will facilitate production of single crystalline, high purity nanostructures utilizing a state-of-the-art molecular beam epitaxy growth environment as well as ample fabrication and measurement instruments. Synthesis and structural and electrical characterization of sub-100 nanometer scale semiconductor materials is essential for application of nano-electronic devices. The project will focus on electrical transport measurements to evaluate the efficacy of these materials in FETs: two and four probe current-voltage relationship, electrical response to applied back-gate potentials, and resistance vs. temperature. The materials to be studied, gallium arsenide (GaAs) and indium arsenide (InAs), both exhibit electrical characteristics determined exclusively by the material due to the presence of Ohmic contacts. GaAs also offers the opportunity to study the effects of highly resistive Schottky barrier contacts. As a necessary step in the utilization of the nano-FETs for biosensing applications, the project will explore selective molecular functionalization of the nanowires via amine-terminated thiol molecules and passivation of the substrate by hydrophobic molecules, improving device functionalities. This NSF EAPSI award is funded in collaboration with the Chinese Ministry of Science and Technology.