| AVS 54th International Symposium | |
| Nanometer-scale Science and Technology | Wednesday Sessions |
| Session NS2+EM-WeA |
| Session: | Nanoscale Devices and Nanowires II |
| Presenter: | P.D. Rack, Oak Ridge National Laboratory |
| Authors: | P.D. Rack, Oak Ridge National Laboratory B.J. Rodriguez, Oak Ridge National Laboratory K. Seal, Oak Ridge National Laboratory S. Jesse, Oak Ridge National Laboratory A.P. Baddorf, Oak Ridge National Laboratory S.V. Kalinin, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Many biological systems respond to stimili such as electrical bias. The application of naturally occurring local biases in biosystems can be mimicked with an atomic force microscope tip. In order to minimize capillary forces and obtain high resolution images of biosystems, a liquid environment, typically with a high ionic strength, is required. A bias applied via traditional cantilevers will cause electrochemical reactions in the solution. The use of shielded probes may allow biases to be applied locally, and minimize any electrostatic force contribution to the signal being measured, whether the tip is used as an electromechanical probe or a probe of local electric force. In this case, the bias is applied locally and the signal is measured locally, both on the nanoscale. The fabrication of suitable shielded probes requires (a) good dynamic properties of the lever, (b) good insulation everywhere except for the apex, (c) high apex conductivity, and (d) apex geometry consistent with high resolution. In this presentation, we describe a process for fabricating shielded probes, and measure their dynamic and electrical properties. The commercial doped-Si tips were coated with an oxide prior to etching a small via (~ 200nm diameter) with a focused ion beam. Subsequent to the via etch, a tungsten contact was deposited in the via using electron beam induced deposition. The dynamic properties of the fabricated probes, as well as their performance in Piezoresponse force microscopy in ambient and liquid environment and I-V characteristics are discussed. The choice of other coatings or other metal plugs may allow for further improvements, and/or tunable properties. The use of shielded probes may allow precise control over the application and measurement of local fields in solution.
Research was sponsored by the Division of Materials Sciences and Engineering (BJR, SJ, SVK) and the Center for Nanophase Materials Sciences (PDR, BJR, KS, APB, SVK), Office of Basic Energy Sciences, U.S. Department of Energy with Oak Ridge National Laboratory, managed and operated by UT-Battelle, LLC.