Optical Microscope; • Scanning Electron Microscope (SEM ...

Nanosprings and nanorings of piezoelec
as-synthesized single-crystal ZnO nanob
typical width of the nanobelt is 30 nm, a
TEM image of a helical nanospring made
The structure model of the ZnO nanobel

Z. L. W

Nanosprings

ctric nanobelts. (a c) SEM images of the
belts, showing helical nanosprings. The
and pitch distance is rather uniform. (d)
e of a single-crystal ZnO nanobelt. (e)
lt.

Wang, Annual Review of Physical Chemistry, 2004, Vol. 55: 159-196

Nanos

SEM image of comb-like nanostructur
polarization induced growth.

Z. L. W

saw

re of ZnO, which is the result of surface

Wang, Annual Review of Physical Chemistry, 2004, Vol. 55: 159-196

Fabrication by simple injection

Kaushik Balakrishnan, et al.

into a poor solvent O

O NO
O
ON
O

J. Am. Chem. Soc. 127(2005) 10496-10497

Twisted Nanobelts

Kaushik Balakrishnan, et al.

J. Am. Chem. Soc. 127(2005) 10496-10497

Seeded growth of ultralong nano

Yanke Che et al. J.

obelts

OOOO O O
N N
O O

Am. Chem. Soc. 129 (2007) 7234-7235

Nanofiber T

10- μm
Nanofiber Net

Technology

Dogs Nose

Video of nanofiber sensor
response to 10 ug Meth simulant
disperse in a filter paper



Video of nanofiber sensor
simulant disperse

r response to 10 ug Meth
e in a filter paper

Nanofibers fabricated from

O O
O
N O

O

1

m an amphiphilic molecules

Nanofibers with anhydride
moieties dominant on surface

Efficient fluorescence
sensing of amines vapor

O O

N O amine

O O NH3

1

Nano Lett., 8 (2008) 2219-2223

SEM images o

The head of a mosquito is mostly
eye. The eyes are compound
eyes, made up of many tiny
lenses.

of bio-species

Claw of a Black Widow spider.
The claw has three hooks, the
middle one used to work the silk.

Walking o

The non-wetting
a, Typical side vi
0.02 mm) just be
Inset, water drop
of 167.6 +/- 4.4°.
images of a leg s
micro-setae (b) a
structures on a s

on water

leg of a water strider.
iew of a maximal-depth dimple (4.38+/-
efore the leg pierces the water surface.
plet on a leg; this makes a contact angle
. b, c, Scanning electron microscope
showing numerous oriented spindly
and the fine nanoscale grooved
seta (c). Scale bars: b, 20 µm; c, 200 nm.

Lei Jiang, Nature 432, p36.

Transmission electron m

Hitachi H9000 UHR TEM:
a dedicated HREM TEM,
capable of 0.18nm point
resolution operating at 300kV

microscopy (TEM)

Detector: CCD (2D imaging)

What is TEM?

 In transmission electron microscopy
electrons are directed toward a thin
scanning required --- helps the high

 These highly energetic incident elec
sample producing characteristic rad
information for materials characteriz

 Information is obtained from both de
transmitted electrons, backscattere
emitted photons.

y (TEM), a beam of highly focused
nned sample (<200 nm). Normally no
h resolution, compared to SEM.
ctrons interact with the atoms in the
diation and particles providing
zation.
eflected and non-deflected
ed and secondary electrons, and

Advantages and Disadv

Advantages:
• High resolution, as small as 0.2 nm.
• Direct imaging of crystalline lattice.
• Delineate the defects inside the samp
• No metallic stain-coating needed, thu

of organic materials,
• Electron diffraction technique: phase i

determination, lattice parameter measure
Disadvantages:
• To prepare an electron-transparent sa

to the conductivity or electron density

antages of TEM

ple.
us convenient for strucutral imaging
identification, structure and symmetry
ement, disorder and defect identification
ample from the bulk is difficult (due
y, and sample thickness).

TEM images: nanobelt

(a) Transmission electron microscopy
ZnO nanobelts. (b) High-resolution TE
electron perpendicular to the top surf

Z. L. Wang, An

y (TEM) image of the as-synthesized
EM image recorded with the incident
ace of the nanobelt.

nnual Review of Physical Chemistry, Vol. 55: 159-196

TEM images: nanobelt

(a) Transmission electron microscopy
SnO2 nanobelts. (b) High-resolution T
incident electron perpendicular to the

Z. L. Wang, An

y (TEM) image of the as-synthesized
TEM image recorded with the
e top surface of the nanobelt.

nnual Review of Physical Chemistry, Vol. 55: 159-196

TEM images: nanobelt

Z. L.

(a) Transmission electron microscopy
(TEM) image of the as-synthesized l-
shaped In2O3 nanobelts. The inset is
the electron diffraction pattern
recorded from the nanobelt. (b) High-
resolution TEM image recorded with
the incident electron perpendicular to
the top surface of the nanobelt.

. Wang, Annual Review of Physical Chemistry, Vol. 55: 159-196

TEM images: nanotube

Imaging single-wall car

rbon nanotube

Jim Zuo’s lab at UIUC

Science, 300, 1419-1421 (2003)

TEM imaging

http://www.popsci.com/gadgets/article/20

g of graphene

010-01/graphene-breakthrough-could-usher-future-electronics

Highly Uniform Nanobelts

Kaushik Balakrishnan, et al.

s by TEM

J. Am. Chem. Soc. 127(2005) 10496-10497

E-diffraction reveals stacki

Kaushik Balakrishnan, et al.

ing conformation

J. Am. Chem. Soc. 127(2005) 10496-10497

Improved fabrication of
nanofibrils: deposited f

solution

Parallel alignment forms fibril arr

f single, uniform
from hot toluene
n

~ 5 nm

rays.

Scanning Probe Microscopy (S

Double functions: scanning and pro
Scanning: piezo raster 2D (X-Y) scan
Probing: sharp tip mounted to a Z-sc

SPM)

obing.
anning;
canner.

Comparison between tradi
microscope

probe Mechanism

Traditional Light/electron Using propertie
waves:

diffraction, defle
scattering

Using interact

SPM Tip between tip and s
mechanic, electro

meganetic.

Note:
SPM cannot replace electron microscop

itional optical and electron
es and SPM

m Sample Resolution

es of High vacuum Å – µm,
ection, chamber,
good for X-Y lateral
Strict sample pre- imaging
treatment (e.g.

conducting stain)
required

tion Usually under Å – nm,
sample: ambient conditions,
ostatic, good for Z-height
. Highly flexible with measurement, thus
other techniques topography imaging

pes, but complementary each other.