Carbon nanotube research has been an extremely active field over the past years. Nanotube materials have unique structural, electrical and mechanical properties, which makes them promising for a range of projected scientific and technological applications. However, significant future efforts are required in order to realize these promises. This research proposes obtaining large-scale arrayed nanotube probe tips and sensors with advanced functions for scanning probe microscopy applications. We also propose obtaining electrical circuits based on arrayed nanotubes networks. The overall motivation is to enable a series of novel nanotube devices useful for scientific and technological applications.
The immediate research goals and activities of this proposed research will include (1) developing controlled chemical vapor deposition methods to synthesize high quality and yield carbon nanotubes materials. (2) Synthesizing nanotubes directly into probe tips and cantilevers for scanning probe microscopy applications. Our approaches will involve combining chemical synthesis (CVD) with top-down nanofabrication methods (such as ebeam lithography). The integration of carbon nanotube tips into arrayed AFM cantilevers could enable a powerful parallel AFM imaging and nanofabrication system. (3) Fabrication and characterization of A-FM cantilevers using individual carbon nanotubes. A defect free carbon nanotube is a perfect one-dimensional crystal that has the highest Young's Modulus among all materials. There is no intrinsic structural mechanism expected in nanotubes for mechanical energy dissipation. Therefore, a nanotube can be utilized as a cantilever to measure extremely small forces. Methods for fabrication and mechanical characterizations of nanotube based cantilevers are proposed. (4) The physics of carbon nanotube electronic devices will be studied. We will start the construction of nanotube electrical circuits at the nanotube synthesis stage. Improving electrical contacts to individual nanotubes by chemical means will be a major focus in this proposed research.
The proposed research will be highly interdisciplinary involving synergetic groups at Stanford University (in Chemistry, Physics and Applied Physics, Electrical and Mechanical Engineering). We will also be interacting closely with our collaborators at NASA Ames Research Center, KLA-Tencor, Park Scientific and other industrial companies. This collaboration has already been initiated recently and some promising results are being generated. The results include (1) the demonstration that carbon nanotube tips provide a solution to the long-standing tip-wear problem in A-FM based nanolithography. (2) Synthesis of bulk single-walled nanotube materials using new chemical vapor deposition (CVD) approaches. And (3) CVD synthesis of nanotubes on flat surfaces containing catalytic particles patterned by nanofabrication techniques. Our collaboration will represent an ideal opportunity to bring together scientists and engineers in different disciplines and institutions; to merge bottom-up chemical synthesis with topdown nanofabrication; and to allow students in different departments to work together and receive broader academic and research training. Thus, the proposed research will be of fundamental and practical significance and will accelerate the impact of nanostructures on real-world problems. ***
