A Pan-style scanning tunneling microscope (STM), with a vertical coarse approach
mechanism, was designed, built and tested. The microscope will be operated in
ultra-high vacuum and also at cryogenic temperatures (8 K) inside a continuous
flow cryostat. Fundamental differences in operating principle exist between the new
microscope and the beetle-type inertial sliders [1] that have been the mainstay of
the group for the last eight years. While Pan-style microscopes do already exist [2],
they remain challenging to build, and an active area of research [3]. This system
represents a bold departure from well-trodden paths, and will greatly expand the range of experiments that our group can perform.
The operating principles of inertial piezoelectric motors are detailed. Design guidelines for a piezoelectric motor are given, and used in the design of the vertical coarse
approach motor. A simple, inexpensive implementation for creating waveforms with
an extremely fast fall time is discussed. Motor performance is tested, and a minimum
step size of 20nm is found for frequencies ranging from 0 Hz to 3 kHz. The motor
operates with high dynamic range: individual 20nm steps can be taken, as well as
being able to move at a velocity of 0.4mm s−1.
Little is known about the vibrational properties of Pan-style microscopes. Vibrational testing of the microscope revealed the expected scanner bending mode at 1.6 kHz (above the scanner bending mode of our beetles at 1.2 kHz), and a complicated
response signal above this frequency. Custom extension springs for an eddy-current
damping system are built and tested. A low resonant frequency of 1.8 Hz is found,
which is ideal for the application.
Initial testing of the STM in ambient conditions is performed on two different
surfaces. A moir´e supermesh [4] with periodicity 3nm is observed on a highly-oriented pyrolytic graphite (HOPG) surface, and agrees well with previously published results.
Using a flame-annealed Gold on mica surface, a low drift rate of 0.6nm s−1 is observed
over a period of 13 minutes. Single-height atomic steps are observed on both surfaces.
Additionally, the microscope is shown to be capable of zooming into different features
on a surface, and scanning at different length scales. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2009-06-24 13:06:16.683
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/1972 |
| Date | 25 June 2009 |
| Creators | Drevniok, BENEDICT |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | 148241447 bytes, application/pdf |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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