Supplementary Information
Deposition of ZnO nanostructured film at room temperature on glass substrates by
activated reactive evaporation
D. Yuvaraja,*, M. Sathyanarayananb, K. Narasimha Raoa
Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore,
India
Department of Physics, Anna University, Chennai 600025, India
Supplementary I
Figure. 1 show the EDAX spectra of the ZnO nanostructured film deposited on Si substrate. Si
peak comes from the Si substrate and the quantification of the spectra
1
Supplementary II
Emission spectra of the plasma before and during zinc evaporation.
To investigate the role of plasma in gas-phase reactions for the formation of ZnO, we
have carried out a detailed study on the chemical species formed in plasma. Radiation emitted
from the plasma generated by hollow cathode glow discharge (HCGD) was collected by optical
fibers kept near it and recorded using a spectrophotometer (HR 4000 UV-Vis, Ocean optics)
from 250 to 1000 nm. The recorded spectra before and during zinc evaporation is shown in the
figures 2a and b. Atomic and molecular species are identified by the characteristic emissions
lines, in the recorded optical spectra. Chemical species present in these spectra are identified
using NIST (National Institute of Standards and Technology [1] databases. Emission peak
centered at 779 and 847 nm are due to O I, and the emission peaks recorded in the plasma during
Zn evaporation occurring at 471 and 635 nm are attributed due to the Zn I (figure. 2). The
ionized oxygen and zinc atoms present in the plasma reacts to form ZnO in the gas phase and the
emission observed at ~ 530 nm is attributed to ZnO green PL band (Fig.1b) [2].
2
Figure. 2 (a and b). Show the Characteristic atomic and ionic emissions spectra recorded
from the plasma before and during zinc evaporation. The emission peaks are indentified and
indexed in the figure using NIST standards.
Photograph of the plasma before and during zinc evaporation.
Figures. 3 a & b show the photograph of the HCGD plasma recorded before and during
the Zn evaporation, the change in the color of the plasma from pale yellowish white to violet is
due to the formation of ZnO and Zn ions. The non uniformity in the plasma emission intensity is
due to difference the density of the ions caused by the non-uniformity in the flow rate of oxygen.
a
b
1cm
1cm
Figure. 3. Shows the photograph of the HCGD generated plasma before (a) and during
Zn evaporation (b).
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Supplementary III
Table. Comparison of the process used in different plasma assisted synthesis.
Technique
Carrier/oxidative gas
ZnO
Proposed growth
and flow rate
nanostructures
mechanism
Reference
synthesized
Carbothermal
Air and nitrogen in the
Long tetrapods
Occurs in gas phase
Wang et
reduction of ZnO
ratio 1:3, flow rate
and nanowires
via vapor-solid
al. [3]
by graphite
0.7-2 L/min.
Flame spray
Oxygen, flow rate
Nanorods and
Occurs in the vapor
Height et
pyrolysis
5 L/min
nanoparticles
phase (flame)
al. [4]
Radio frequency
Carrier gas (nitrogen),
plasma assisted
flow rate 2.5 L/min.
Nanorods,
Occurs in the
Peng et al.
evaporation
Oxidative gas (oxygen),
bipods, tripods
vapor phase
[5]
flow rate 0.5 - 50 L/min
and tetrapods
(plasma)
glow discharge
Oxygen, flow rate
Nano flowers
Occurs in gas phase
Present
plasma assisted
0.7L/min
(marigold and
via vapor-solid
work
reactive
rose –like
mechanism
evaporation
structure )
mechanism
Hollow cathode
4
Supplementary IV
Figure. 4. The variation of number of charge carriers with time for ZnO nanostructured film c
(inset) Ohmic I-V characteristic of the Al electrodes and ZnO nanostructured film.
Reference for supplementary information
[1] http://physics.nist.gov
[2] S. Acquaviva, E. D. Anna, M. L. D. Giorgi: J. Appl. Phys. 102, 073109 (2007)
[3] Y. G. Wang, M. Sakurai, M. Aono, Nanotechnology 19, 245610 (2008)
[4] M. J. Height, L. Madler, S. E. Pratsinis: Chem. Mater. 18, 572 (2006)
[5] H. Peng, Y. Fangli, B. Liuyang, L. Jinlin, C. Yunfa: J. Phys. Chem. C 111, 194 (2007)
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