Annual Report 2012 - Latvijas Universitātes Cietvielu fizikas institūts

CONTROLLED MANIPULATION AND MECHANICAL
CHARACTERIZATION OF NANOWIRES
B. Polyakov, P. Kulis, S. Vlassov, L. Dorogin, I. Kink, R. Lohmus
One-dimensional solids such as nanowires (NWs) and nanotubes (NTs) exhibit
many unique optical, electrical, mechanical, and other properties that make them
candidates for numerous future nanoscale devices.
In many applications NWs are subjected to
mechanical stresses and deformations. In flexible
electrodes, as well as various
nanoelectromechanical systems (NEMS) like, e.g.,
nanorelays, nanoswithces and nanoresonators,
NWs are required to withstand numerous repetitive
deformations. The investigation of NWs
mechanical characteristics is of a great importance
for performance of the named systems.
The manipulation of NWs or NTs is
frequently employed to position and assemble
prototype nanodevices. Depending on the
magnitude of its static friction and its ultimate
strength, a NW may be displaced or broken as a result of manipulation. Static friction of
NW on flat substrates is strong enough to maintain even highly deformed NWs in a bent
state, which produces high strain and is especially important for piezoelectric materials
such as zinc oxide.
Young’s modulus, bending strength or yield strength of copper oxide (CuO), zinc
oxide (ZnO) and silver (Ag) NWs were measured in situ using nanomanipulation
techniques inside a scanning electron microscope
(SEM). Young’s modulus was measured by
bending half-suspended NWs and simultaneously
measuring the force using a sensor based on a
Gradual bending and fracture of a ZnO NW during controlled
loading by AFM tip inside SEM (a-f). Calculated the “most
bent state” laid over the SEM image was used to estimate
static friction and strength of NW (e).
quartz tuning fork. Bending strength was measured for the NWs on a flat surface by
bending them from one end with an AFM tip until the NW breaks or plastically deforms.
The profile of the elastically deformed NW and the average value of Young’s modulus
were used to calculate the bending strength or yield strength of the NWs.
Scientific Articles
1. P. Kulis, J. Butikova, B. Polyakov, G. Marcins, J. Pervenecka, K. Pudzs, I. Tale.
Work function of colloidal semiconducting nanocrystals measured by Kelvin probe, IOP
Conf. Ser.: Materials Science and Engineering, 38, 012048, 2012.
2. J. Butikova, G. Marcins, B. Polyakov, A. Muhins, A. Voitkans, I. Tale. Processing
of amorphous Si by pulsed laser irradiation at different wavelengths, IOP Conf. Ser.:
Materials Science and Engineering, 38, 012009, 2012.
3. B. Polyakov, L. Dorogin, S. Vlassov, M. Antsov, P. Kulis, I. Kink, R. Lohmus. In
situ measurements of ultimate bending strength of CuO and ZnO nanowires, European
Physical Journal B, 85, 366, 2012.
4. B. Polyakov, S. Vlassov, L. Dorogin, P. Kulis, I. Kink, R. Lohmus. The effect of
substrate roughness on the static friction of CuO nanowires, Surface Science. 606, 1393-
1399, 2012.
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