Conductance Microscopy for Electric Conduction Study of Bio-Inspired Hybrid Nanostructures under Ambient Conditions
- PDF / 559,250 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 76 Downloads / 164 Views
NN1.4.1/C1.4.1
Conductance Microscopy for Electric Conduction Study of Bio-Inspired Hybrid Nanostructures under Ambient Conditions Wahyu Setyawan, Saleem Rao, and Seunghun Hong. Physics, Center for Material Research and Technology, and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4351, U.S.A. ABSTRACT Electrical conductance of single stranded DNA (5'-TTT TTT TTT T/3 Thio MC3-D/-3') monolayer patterns on Au surface is compared with those of various organic molecular patterns via the conductance microscope (CM) technique that allows one to take nanoscale conductance images utilizing a conducting AFM tip in contact mode AFM. In the experiment, reference molecules and ssDNA are patterned on the same substrate via direct deposition methods such as dip-pen nanolithography and microcontact printing. Then, conductance microscope image is recorded revealing the relative conductivity of ssDNA patterns relative to various reference molecules. 16-mercaptohexadecanoic acid and 2-mercaptobenzimidazole patterns are found conducting better than the ssDNA patterns. This result indicates that the ssDNA with 10T bases is a relatively poor electrical conductor. The capabilities of CM technique are also tested on various nanostructures including the single wall carbon nanotube junction. INTRODUCTION Towards bio- and molecular electronics, many researchers have been investing extensive efforts to study the electrical properties of DNA and other organic molecules. Various theoretical models explaining the charge transport in organic molecules have been proposed.1-3 Many experimental works also have been done by investigating DNA molecules on the nanogap electrode4 or by studying mixed monolayers of DNA and mercaptohexanol (MCH)5 via the scanning tunneling microscope method. However, the measurement of electric conduction in small organic molecular wires is still extremely difficult, and the conduction mechanism in DNA molecules is still controversial. If one could find an experimental tool that allows us to reliably characterize short molecular nanowires like conventional "I-V stations" in microelectronics labs, he/she can remove one significant bottle neck which has been holding back the development of molecular electronics. In this manuscript, we applied the conductance microscope (CM) technique to characterize well-defined organic molecular patterns generated via dip-pen nanolithography (DPN) or microcontact printing. The conductance images from the sample with two different molecular patterns allow us to reliably measure the relative conductance of two different organic molecular species. In the following, we will first address several important aspects in measuring nanoscale conductance under ambient conditions via CM. Then, we will present the relative conductance data of ssDNA molecules relative to various reference molecules.
NN1.4.2/C1.4.2
EXPERIMENTAL DETAILS Figure 1 shows the basic experimental set up of CM. In the measurement, the conducting AFM tip is in direct contact with the surfa
Data Loading...
