June 18, 2006
June 18, 2006
June 21, 2006
Division Experimentation & Lab-Oriented Studies
11.76.1 - 11.76.13
A Nanotechnology Experiment: Design of Low Cost Scanning Tunneling Microscopes
ABSTRACT This paper describes a set of laboratory exercises where upper-level undergraduate engineering students constructed and tested low-cost scanning tunneling microscopes (STM) of their own designs as an assignment for a nanotechnology course taught during Spring 2005. Before attempting the design task, students were exposed to nanotechnology instrumentation principles, commercial-grade scanning probe microscopes, current design methods and a number of design examples from literature. Three design objectives were met: each instrument cost below $500, a sustainable tunneling current was achieved and calculations predicted atomic-resolution capabilities of the designed instruments. While the scans of highly oriented pyrolytic graphite showed surface characteristics the microscopes could not distinguish individual atoms.
1. Introduction Nanotechnology is one of the most vibrant research areas today. Some of the research is in the commercialization stage, like carbon nanotube applications in computer monitors or energy storage devices. In academia, at the graduate level, there was a substantial number of course offerings dealing with various nanotechnology topics. There were fewer successful attempts in presenting this material to the undergraduate student population, mostly in sciences, while only a handful of isolated reports documented nanotechnology topics in undergraduate engineering curricula1.
During the Spring 2005 semester, a design-based nanotechnology course was offered to upper-level undergraduate industrial engineering students. The course presented an implementation of McCarthy’s2 version of the Kolb3 learning cycle and was motivated in part by work presented by Harb et al4. A large portion of the course lab segment was dedicated to the design, construction and testing of scanning tunneling microscopes (one of the major instruments in nanotechnology research) of students’ own designs. Three engineering criteria were specified: the cost of each STM (not including the PC) below $500, the tunneling current duration long enough to perform at least one full scan, and the device capability to achieve atomic resolution.
2. Previous Work on Low-Cost Scanning Tunneling Microscopes
Scanning tunneling microscopes present a major tool for nanotechnology imaging and manipulation. Since their invention in 1980’s5, they were an important topic of instrumentation research. STM commercialization encouraged their use in many materials laboratories. However, STMs’ high cost ($10,000 for a student version device or $50,000 or more for a research-grade device) limited their use to mainly larger institutions. Even there, undergraduate students are usually not given an opportunity to work with these high-level research instruments.
Jaksic, N. (2006, June), A Nanotechnology Experiment: Design Of Low Cost Scanning Tunneling Microscopes Paper presented at 2006 Annual Conference & Exposition, Chicago, Illinois. 10.18260/1-2--1309
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