Optimization of electrochemically etched tungsten tips for scanning tunneling microscopy

CHED 155

Zachary Cordel, Zachary.cordel@western.edu1, Grover Holmes, grover.c.holmes@us.army.mil2, and Dustin Hite1. (1) Department of Natural and Environmental Sciences, Western State College of Colorado, Gunnison, CO 81231, (2) 1007B W. Denver Ave., Gunnison, CO 81230
Since the invention of the scanning tunneling microscope (STM) in 1983, scanned probe microscopy has become a widespread tool in many analytical laboratories. The shape, size and cleanliness of a STM tip are crucial to the performance of the microscope. In this project, our goal is to vary systematically the parameters affecting the fabrication of tips from electrochemically etched tungsten wire. We have characterized our tips through an analysis of cone angle and radius of curvature as measure by scanning electron micrographs. Among the critical parameters affecting tip shape, which include voltage cutoff time, depth of W in solution, and molarity of solution, our data reveal a strong dependence on the geometry of the counter-electrode on tip sharpness.
 

Undergraduate Research Poster Session: Analytical Chemistry
11:00 AM-1:00 PM, Monday, 27 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster

Division of Chemical Education

The 231st ACS National Meeting, Atlanta, GA, March 26-30, 2006