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A G R E AT E R M E A S U R E O F C O N F I D E N C E noscale structures.
An excellent example is the carbon nano-
tube (CNT). CNTs can be manufactured to
consist of a single sheet of carbon atoms ori-
ented in a graphite-like structure, rolled up
into the shape of a tube only a few nanome-
ters in diameter [2]. The smallest diameter
tubes are insulators (i.e., large bandgap mate-
rials). As the diameter of the CNT increases,
its bandgap decreases. With a large enough
diameter, a CNT can become a semiconduc-
tor. At even larger diameters, CNTs exhibit
metallic properties, acting like conductors.
Structure and Behavior
of the Very Small
Electrical
Particle size and structure have a major
influence on the type of measurement tech-
nique used to investigate a material. Macro-
Measurements On
scopic materials can be viewed with optical
microscopes. For nanoscopic materials with
particles smaller than 200 nanometers, a
Nanoscale Materials scanning tunneling microscope (STM) or
an Atomic Force Microscope (AFM) can
be used. Table 1 outlines the relative sizes
of particles considered as nanoscopic, meso-
scopic, and macroscopic.
James Niemann Table 1. Relative sizes of various particle
Keithley Instruments, Inc. classifications.
Classification Particle Size
Macroscopic >300nm
This tutorial explains the importance of sile strength, phase transition temperature,
Varies with phase
electrical measurements to the science of weight, hardness, electrical and thermal con- Mesoscopic
coherence length
nanotechnology, and presents practical ductivity, etc. Nanotechnology offers ways Nanoscopic 0.5