Remember, the x,y, and z actuators are piezoelectric actuators (? pressure by ? electric field or ? electric field by ? pressure). A response curve of one of these actuators sold by Newport optics company is seen in the graph at right. Assume we are

1
Remember, the x,y, and z actuators are
piezoelectric actuators (? pressure by ? electric
field or ? electric field by ? pressure).A
response curve of one of these actuators sold by
Newport optics company is seen in the graph at
right. Assume we are talking about the
x-piezo Approximately what range of voltage
is necessary to achieve a 20 micron scan range?
2
Piezoelecticity
piezoelectric crystal drawings drawings by W.T.
Neff
These may be naturally occuring piezoelectric
crystals such as quartz (SiO2).
These appear to be manufactured piezoelectric
crystals such as lead zirconate titanate (PZT).
3
Which of these 3 image points is highest in the
object ?
This is z height plotted as colors or shades of
grey. It could also be plotted as voltage sent
to the z piezo. Approximately how much higher is
this dna molecule than the background it is on?
Above is a view of an AFM tip as if you were
looking up from the sample (from MikroMasch
company). The z-resolution in AFM is defined by
the feedback loop and the z-piezoelectric
actuator. The x/y resolution is defined by x/y
actuators (not in the feedback loop) and the
shape and size of the tip (see above middle).
x/y detail is less reliable than z for this
reason.
3D rendering of same type of topography data seen
at top right.
4
To make AFM probes, start with a large (4 inch
maybe) Si wafer and use photolithographic
techniques to remove selected material.
Essentially sculpting our probe from a piece of
bulk silicon (with other materials). This is the
same technology that makes transistors on
computer chips. The more computer chips or afm
tips we can get from one wafer of Si, the cheaper
they become (top drawing of alternate method that
still involves lithography and silicon is from
ThermoMicroscopes company).
5
From PNI manual
6
http//www.sensortech.ca/
Piezoelectricity (from pressure electricity) is
a property of certain classes of crystalline
materials including natural crystals of Quartz,
Rochelle Salt and Tourmaline plus manufactured
ceramics such as Barium Titanate and Lead
Zirconate Titanates (PZT). When mechanical
pressure is applied to one of these materials,
the crystalline structure produces a voltage
proportional to the pressure. Conversely, when an
electric field is applied, the structure changes
shape producing dimensional changes in the
material. The piezoelectric materials from Morgan
Electro Ceramics use polycrystalline ceramics
instead of natural piezoelectric crystals. These
are more versatile with physical, chemical and
piezoelectric characteristics able to be tailored
to specific applications. The hard, dense
ceramics can be manufactured in almost any given
shape or size. They are chemically inert, and
immune to moisture and other atmospheric
conditions. Morgan Electroceramic, as part of a
group which is a world leader in Advanced
Ceramics, has piezoelectric RD and manufacturing
facilities in Southampton, England Ruabon, Wales
and Bedford, Ohio. Historical NoteThe
Piezoelectric effect was discovered byPierre
Curie (1859-1906) in the early 1880's.
7
Silicon AFM probe
z
x
y
www.ipht-jena.de/typo3temp/pics/8a3180fa14.jpg
Final tip radius can be lt1nm. Often tip damage
and contamination make this tip radius much
larger than 1nm (see below)
z
From Mikromasch http//www.spmtips.com/dgp/150/gp
x
y
8
Specialized C nanotube tips
www.xintek.com