How to make Thinfilm

Objective
Because of poor functioning of conventional SiO2 semiconductor based transistor as mentioned
above many researcher have been working in the eld of EDLT. This paper also aims
to,
i Understand the physics behind the EDL and fabricate the EDL TFTs which has a
property of high carrier mobility, small thresold voltage etc.
ii Study the optoelectronic properties of ZnO thin lm and nature of graph as mentioned
below.
iii To grow the researcher's interest in the eld of ZnO thin lm EDLT.
4 Methodology
4.0.1 Film Growth and Characterization
Thin lm ZnO can be prepared by many methods and technique such as molecular beam
epitaxy,atomic layer epitaxy, chemical vapor deposition, spray pyrolysis, sol-gel method,
pulsed laser deposition,magnetron sputtering, electron beam evaporation, spin coating,thermal
evaporation, electrochemical deposition, reactive evaporation.Each of the technique has their
own advantage and disadvantage but among all of these techniques, sol-gel method attracts
much attention because it is low in cost, simple deposition equipment, easier adjustment of
composition,able to carry out doping at molecular level, and easy fabricate on large area
lms.
Initially the substrate (quartz, glass or silicon -wafer) is cleaned with chemical (acetone +
ethanol + isopropanol) using ultrasonic machine for 10 minutes to remove the contaminants
on the surface of the substrate. Zinc acetate dehydrate has to be dissolved in mixture of
2-methoxyethanol and mono-ethanolamine. After that, the mixture solution is stirred by
using a magnetic stirrer at 600C for 2 hours using a hot plate and stirrer. The solution is
then left for 24 hours at room temperature. Solution is coated on a substrate (quartz, glass,
and silicon) at 3000 rpm for 60 seconds. Then precursor thin lms (sample) is heated at
1500C for 10 minutes and after that, coating and heating process were repeated for 10 times
depending on the thickness of the solution (ZnO). The lms is inserted into the furnace and
annealed in ambient atmosphere at several temperatures (4000C, 5000 and 6000C) [13].
The structural analysis of ZnO thin lms is carried out using a X-ray di ractometer with
a CuK ( = 1:5406 A
) as an X-ray source.The X-ray di raction (XRD) analysis is done to
check crystalline quality of the lms. The lattice parameters, d-spacing, texture coe cient
(TC), crystalline size (D), lattice strain( )are calculated from the XRD data. Morphology
studies were carried out using a scanning electron microscope (SEM).The XRD patterns of
ZnO thin lms deposited on glass substrates using sol-gel spin coating method with various
precursor concentrations are shown in the Fig5 [14]
Figure 5: XRD patterns of ZnO thin lms with various precursor concentrations and
annealed at 800oC
4.0.2 Device Fabrication and Measurement
After the fabrication of zno thin lm PEG-FETs(Polymer electrolyte-gated eld-e ect transistor)
is fabricated in a manner shown in g.6 The source, drain and gate electrodes of
TFT will be made by the thermal evaporation of the Au/Cr.Spin coating is used to form
the polymer semiconductor layer, followed by thermal evaporation of metal electrodes and
drop-casting of the polymer electrolyte dielectric layer.In this case, an electric double layer is
formed at the polymer semiconductor/polymer electrolyte interface [4].Then we will perform
various optoelectronic measurements.
Figure
In the present era of scarcity of water resources, e ective treatment of wastewater is a major
prerequisite for growing economy. It is critical to develop and implement advanced wastewater
treatment technologies with high e ciency and low capital requirement. Among various
treat-ments, recent advanced processes in nano-material sciences have been attracting the
attention of scientists. However, limited collective knowledge is available in this context.
The present manuscript reviews the potential developments in nanotechnology with respect
to wastewater treatment. The article reviewed and discussed utilization of various classes of
nano-materials for wastewater treat- ment processes. This includes four main classes; First,
nano-adsorbents such as activated carbon, carbon nanotubes, grapheme, manganese oxide,
zinc oxide, titanium oxide, magnesium oxide and ferric oxides that are usually applied for
removal of heavy metals from the wastewater. Second, nano-catalysts such as photocatalyst,
electrocatalyst, Fenton based catalyst, and chemical oxidant have been shown the potential
for removing both organic and inorganic contaminants. Third, nano-membranes have
been used for e ective removal of dyes, heavy metals and foulants using carbon nanotube
membranes, electrospun nano bers and hybrid nano-membranes. Finally, theintegration
of nanotechnology with biological processes such as algal membrane bioreactor, anaerobic
digestion and microbial fuel cell is discussed with respect to its potential for wastewater
puri cation. 2016 The Authors.