Scanning
tunneling
microscope (STM) is a powerful technique for viewing surfaces at the atomic
level. Its development in 1981 earned its inventors, Gerd
Binnig and Heinrich Rohrer (at IBM Zürich), the Nobel Prize in Physics in
1986[1][2]. STM probes the density
of states of a material using tunneling
current. For STM, good resolution is considered to be 0.1 nm lateral resolution and 0.01 nm depth resolution[3]. The STM can be used not only in
ultra high vacuum
but also in air and various other liquid or gas ambients, and at temperatures ranging from near 0 kelvin to a few
hundred degrees Celsius[4].
Technique
for revealing the apparent electron-density-related atomic structure of surfaces, using
a needle-like probe near the object under observation; a tunnelling current,
which is measured, is generated by altering the potential at the tip of the
probe; a 3D representation of the sample surface is generated by rastering
the surface of the object and mapping the distance for constant current level
at various points
A
scanning probe microscopy
instrument capable of revealing the structure of samples. The STM uses a
sharp metal tip positioned over a conducting substrate
with a small potential difference applied between them. The gap between the
tip and substrate
surface is small enough so that electrons
can tunnel between the tip and the surface. The tip is then scanned across
the surface and adjusted to keep a contact current flowing. By recording the
tip height at each location a "map" of the sample surface is
obtained.
A
device that obtains images of the atoms on
the surfaces of materials - important for understanding the topographical and
electrical properties of materials and the behaviour of microelectronic
devices. The STM is not an optical
microscope; instead it works by
detecting electrical forces with a probe that tapers down to a point only a
single atom
across. The probe in the STM sweeps across the surface of which an image is
to be obtained. The electron
shells, or clouds, surrounding the atoms on
the surface produce irregularities that are detected by the probe and mapped
by a computer into an image. Because of the quantummechanical
effect called 'tunnelling' electrons
can hop between the tip and the surface. The resolution of the image is in the order of 1nm or
less.
A
scanning probe technique where a local metallic probe is scanning a
conductive surface. The topographic information is deduced from the tunnel
current which runs between probe and sample without mechanical
contact. The electron
shells, or clouds, surrounding the atoms on
the surface produce irregularities that are detected by the probe and mapped
by a computer into an image.
A
device that obtains images of the atoms on
the surfaces of materials - important for understanding the topographical and
electrical properties of materials and the behaviour of microelectronic
devices. The STM is not an optical
microscope; instead it works by
detecting electrical forces with a probe that tapers down to a point only a
single atom
across. The probe in the STM sweeps across the surface of which an image is
to be obtained. The electron
shells, or clouds, surrounding the atoms on
the surface produce irregularities that are detected by the probe and mapped
by a computer into an image. Because of the quantummechanical
effect called 'tunnelling' electrons
can hop between the tip and the surface. The resolution of the image is in the order of 1nm or
less.