Indonesi
an
Journa
l
of El
ect
ri
cal Engineer
ing
an
d
Comp
ut
er
Scie
nce
Vo
l.
1
3
,
No.
3
,
Ma
rch
201
9
, p
p.
1079
~
1
0
8
6
IS
S
N:
25
02
-
4752, DO
I: 10
.11
591/ijeecs
.v1
3
.i
3
.pp
1079
-
1
0
8
6
1079
Journ
al h
om
e
page
:
http:
//
ia
es
core.c
om/j
ourn
als/i
ndex.
ph
p/ij
eecs
I
mp
ac
t
of anne
ali
ng temp
eratu
re
t
o t
h
e per
formanc
e of
hematit
e
-
based
h
um
idi
ty
sensor
W.R.W.
Ahm
ad
1
, M
.H. M
am
at
2
, Z
. K
hus
aimi
3
, A.S. Is
mail
4
, M.
Ru
s
op
5
1
,2,4,5
NANO
-
El
ec
Tronic
Cen
tre (
NET)
,
Fa
cult
y
o
f
Elec
tr
ical Engi
nee
ring
,
Univ
ersit
i Te
kno
logi
M
ARA
(UiTM
),
Malay
s
ia
2
,3,5
NANO
-
SciT
ec
h
C
ent
r
e
(NS
T
),
Insti
tut
e
of
Sci
enc
e
(IOS
),
Uni
ver
siti
Te
kno
log
i
MA
RA (UiT
M),
Mal
a
y
s
ia
Art
ic
le
In
f
o
ABSTR
A
CT
Art
ic
le
history:
Re
cei
ved
Sep
1,
2018
Re
vised N
ov
2
0,
2018
Accepte
d Nov
30
, 201
8
In
the
pre
sen
t
s
tud
y
,
h
emati
t
e
(
α
-
Fe
2
O
3
)
nanor
o
d
struct
ur
e
wer
e
grown
on
fluori
ne
doped
ti
n
oxide
co
at
e
d
gla
ss
subs
tra
te
via
sonicated
imm
ersion
appr
oac
h
wi
th
var
iation
of
ann
e
al
ing
t
empera
t
ur
e
(350˚C
–
600˚C)
in
one
-
hour
treatment
.
The
impact
of
v
ar
y
ing
the
te
m
pe
rat
ure
of
anne
a
ling
treatment
on
cr
y
st
alline
p
hase
,
struc
ture
m
orpholog
y
,
op
t
ic
a
l
prope
rt
ie
s
a
nd
hum
idit
y
sensing
per
form
anc
e
of
hematit
e
were
exa
m
ined.
X
-
ra
y
diff
racti
on
pa
tt
er
n
dis
cl
osed
a
rho
m
bohedr
al
struc
ture
with
α
-
pha
se
diffr
ac
t
ion
pea
ks.
Th
e
surfac
e
m
orphol
og
y
imag
es
ta
k
en
from
fie
ld
e
m
ission
sca
nning
el
e
ct
ron
m
ic
roscop
y
rev
e
al
ed
th
at
the
h
e
m
at
it
e
nanor
od
a
rra
y
s
were
grow
n
uniforml
y
in
al
l
sam
ple
s
a
nd
the
av
era
g
e
dia
m
et
ers
of
n
a
norods
were
m
ea
sured
in
th
e
ran
ges
bet
w
ee
n
55
and
80
nm
.
U
lt
rav
io
let
–
visibl
e
spec
troscop
y
m
ea
surem
ent
spec
tra
show
that
al
l
sam
ple
s
exh
ibi
te
d
good
op
tical
prop
ert
i
es.
T
he
hematit
e
hum
idi
t
y
sensor
sam
ple
ann
eal
ed
a
t
400°C
h
a
s
demons
tra
te
d
the
high
est
sens
it
ivi
t
y
resp
onse
(S=177.
78
)
to
hum
idi
t
y
ran
ge
b
et
wee
n
40%RH
to
90%RH.
Ke
yw
or
d
s
:
Anneali
ng
te
m
per
at
ur
e
Hem
atite
Hu
m
idit
y
senso
r
Sens
it
ivit
y
Sonica
te
d
im
m
ersio
n
Copyright
©
201
8
Instit
ut
e
o
f Ad
vanc
ed
Engi
n
ee
r
ing
and
S
cienc
e
.
Al
l
rights re
serv
ed
.
Corres
pond
in
g
Aut
h
or
:
Wan Rosm
aria
W
a
n Ah
m
ad,
NAN
O
-
Ele
cT
r
on
ic
Ce
ntre (
N
ET), Fac
ulty
o
f
Elec
tric
al
Eng
ineerin
g,
Un
i
ver
sit
i Te
knol
og
i M
ARA
(U
iTM
)
,
40450 S
hah A
l
a
m
, S
el
ango
r,
Ma
la
ysi
a.
Em
a
il
: ro
sm
ari
a@sala
m
.u
itm
.
edu.m
y
1.
INTROD
U
CTION
Mon
it
ori
ng
a
nd
co
ntr
olli
ng
the
le
vels
of
m
oistur
e
an
d
hum
idit
y
are
consi
der
a
bly
vibra
nt
in
var
i
ou
s
env
i
ronm
ents
par
ti
cula
rly
for
industrial
s,
m
anufactu
rin
g,
e
nv
i
ronm
ental
,
and
m
edical
fiel
ds
.
T
he
dem
and
of
ideal
hu
m
idit
y
sensor
with
l
ow
c
os
t
m
anu
factur
i
ng
as
w
el
l
as
hig
h
effi
ci
ency
is
esse
ntial
ly
cru
ci
al
.
An
ultim
at
e
hu
m
i
dity
sens
or
shou
l
d
m
eet
sp
eci
al
requirem
e
nts
s
uch
as
hi
gh
se
ns
it
ivit
y,
excell
ent
sta
bi
li
ty
and
rep
eat
a
bili
ty
,
a
nd
fast
res
ponse
/reco
ver
y
rat
e.
Va
rio
us
ty
pe
s
of
hum
idity
sens
or
s
s
uc
h
as
capa
ci
ti
ve
[
1]
a
nd
resist
ive
[2
]
-
[
6]
wer
e
stud
ie
d
for
dif
fer
e
nt
app
li
cat
io
n
s
.
A
m
on
g
these
ty
pes,
re
sist
ive
hum
idity
senso
r
is
on
e
of
the
prom
isin
g
se
nsors
for
hu
m
idit
y
and
va
por
detect
io
n,
based
on
it
s
sim
pl
ic
it
y
of
fa
bri
cat
ion
pr
oces
s,
low
cost,
an
d
relat
ivel
y
high
preci
sion
of
se
nsor
m
easur
em
ent
[7
]
.
To
f
ab
ricat
e
high
-
e
ff
ic
ie
nc
y
hu
m
idit
y
sensors
,
var
i
ou
s
m
at
eri
al
s
hav
e
bee
n
synthesiz
ed
a
nd
ex
plored
,
w
hich
inclu
de
polym
ers,
cera
m
ic
s,
m
e
ta
l
ox
ide,
an
d
their c
om
po
sit
es. Eac
h
m
at
eri
al
h
as it
s
own virtue
and e
xac
t
conditi
ons
of
util
iz
at
ion
s
.
Me
ta
l
ox
ide
s
e
m
ic
on
duct
ors
are
t
he
m
os
t
com
m
on
m
at
e
rial
s
us
e
d
for
el
ect
ro
nic
s
ens
ing
de
vices
because
of
the
ir
excell
ent
pr
op
e
rtie
s.
Me
ta
l
ox
ides
m
at
erial
s
hav
e
al
so
been
util
iz
ed
in
hu
m
idit
y
s
ens
or
dev
el
op
m
ent
.
These
m
et
al
ox
i
des
incl
ud
e
TiO
2
[
8],
SnO
2
[
9],
an
d
Zn
O
[4
]
.
O
ne
of
the
po
ssi
ble
m
e
tal
ox
id
e
m
at
erial
s
that
rar
el
y
re
ported
to
be
a
pp
li
ed
as
hum
idit
y
sens
or
is
iro
n
oxides
(f
e
rr
ic
oxides
).
Iro
n
oxid
e
par
ti
cula
rly
hem
at
i
te
ph
ase
exh
i
bits
n
-
ty
pe
sem
ic
on
duct
or
with
a
wide
ba
ndga
p
of
2.1
eV.
Early
studi
es
of
synthesiz
in
g
ir
on
oxides
to
be
ap
plied
as
hu
m
idit
y
senso
rs
m
erely
fo
cu
sin
g
on
por
ous
ce
ram
ic
m
at
erials
with
lim
it
ed
char
ac
te
rizat
ion
res
ul
ts
[1
0].
The
eff
ect
s
of
dif
f
eren
t
do
pan
t
ion
s
to
the
he
m
at
i
te
-
base
d
hum
idit
y
Evaluation Warning : The document was created with Spire.PDF for Python.
IS
S
N
:
2502
-
4752
Ind
on
esi
a
n
J
E
le
c Eng &
Co
m
p
Sci,
Vo
l.
1
3
, N
o.
3
,
Ma
rc
h
201
9
:
1079
–
1
0
8
6
1080
sens
or
be
ha
vior
ha
ve
al
so
bee
n
inv
e
sti
gated
[11].
Iro
n
oxid
e
m
inerals
has
been
e
xisti
ng
t
o
be
poly
m
or
phs,
as
it
can
be
fou
nd
in
se
ver
al
ph
ases
,
for
instance
,
hem
a
ti
te
(α
-
Fe
2
O
3
),
beta
-
phase
ir
on
ox
i
de
(β
-
Fe
2
O
3
),
m
agh
em
it
e
(γ
-
Fe
2
O
3
),
e
ps
il
on
-
phase
iro
n
oxide
(ε
-
Fe
2
O
3
)
and
the
m
ixed
ox
ide
,
m
agn
et
it
e
(F
e
3
O
4
).
He
m
at
i
te
(α
-
Fe
2
O
3
)
is
on
e
of
the
ir
on
ox
ides
that
a
re
com
m
on
ly
fou
nd
in
a
rock
an
d
it
is
t
he
m
os
t
du
rabl
e
an
d
env
i
ronm
ental
l
y
fr
ie
ndly
un
de
r
a
broa
d
ra
nge
of
s
urr
ound
ing
c
onditi
ons
[12].
Pa
rtic
ular
ly
in
na
no
st
ru
c
tures,
the
highli
ghte
d
cha
racteri
sti
cs
of
h
e
m
at
i
te
wer
e
captur
e
d
i
n
va
rio
us
a
pp
li
cat
io
ns
inclu
ding
photo
el
ect
r
oc
hem
ic
al
w
at
er spli
tt
ing
[
13]
, ma
gn
et
ic
de
vices
[
14
]
, a
nd li
thi
um
ion
b
at
te
rie
s
[
15
]
.
Nu
m
erous
na
nostr
uctu
res
of
hem
atite
hav
e
been
synt
hesiz
ed
t
hroug
h
va
r
iou
s
synt
hesis
te
chn
iq
ues
and
m
at
erial
s
com
po
sit
ion
s
.
Synthesis
a
nd
fabrica
ti
on
process
of
hem
atite
nan
oro
d
ar
ray
str
uctu
re
dev
el
op
m
ent
is
influ
e
nce
d
by
diff
e
re
nt
f
eat
ur
es
s
uch
as
tem
per
at
ure
[16]
,
natu
re
of
precu
rs
ors
[17],
sta
bili
zers,
an
d
su
bs
trat
es
.
Lit
erall
y,
the
revoluti
on
of
enhanced
nanostr
uc
tures
co
ntri
bute
s
un
iq
ue
eff
e
ct
s
on
structu
ral,
opti
cal
,
an
d
el
ect
ri
cal
perform
ance.
S
om
e
research
ers
al
so
a
dd
ed
dopa
nts
to
t
heir
s
olu
ti
on,
f
or
t
he
pur
po
se
d
of
e
nhanci
ng
t
he
he
m
at
i
te
nan
ost
r
uctu
re
pro
p
e
rtie
s
[18
]
,
[
19
]
.
T
hese
resea
rc
h
works
ha
ve
br
ought
a
lot
of
at
te
ntio
n
to
e
xp
a
nd
app
li
cat
io
n
rel
at
ed
to
hem
atite
m
a
te
rial
.
In
di
rectl
y,
al
l
t
hese
feat
ur
es
excit
e
com
m
un
it
y
at
t
ention
in
dev
el
op
i
ng
the
a
pp
l
ic
at
ion
s
with
va
riat
ion
m
et
ho
d
pr
e
pa
rati
ons.
Sever
al
ap
pro
aches
to
synthesiz
e
this
m
at
erial
are
sp
i
n
coati
ng
de
po
sit
io
n,
so
l
–
gel
m
e
tho
d,
hy
drothe
r
m
al
synthesis,
sp
ray
pyr
olysi
s,
and
m
agn
et
ron
s
pu
tt
eri
ng
with
disti
nct
m
or
phologies
an
d
nanostr
uctu
re
s.
To
gro
w
α
-
Fe
2
O
3
nano
rod
ar
rays,
the
hydrot
herm
al
m
et
ho
d
i
s
m
os
t
co
m
m
on
l
y
us
ed,
w
hich
requires
a
hi
gh
-
press
ur
e
a
uto
c
la
ve
at
h
ig
h
te
m
per
at
ur
e a
nd lo
ng
depositi
on ti
m
e
[
20
]
,
[
21
]
.
A
pro
per
a
nn
e
al
ing
treat
m
ent
in
po
st
-
sy
nth
e
sis
pr
oc
ess
is
essenti
al
in
i
m
p
rovin
g
la
tt
ic
e
s
tructu
re
a
nd
interfacia
l
co
nductivit
y
bet
w
een
the
FTO
s
ub
st
rate
an
d
t
he
hem
at
it
e
fil
m
[1
6].
T
he
refor
e
,
in
this
res
earch
work,
we
pr
e
pa
re
d
hem
at
it
e
nano
rods
sam
ples
us
in
g
sonic
at
ed
im
m
ersion
m
et
ho
d
an
d
ann
eal
e
d
at
dif
fer
e
nt
tem
per
at
ur
es
.
The
i
nf
l
uen
ce
s
of
a
nn
e
al
ing
tem
per
at
ure
on
the
str
uctu
ral
,
op
ti
ca
l,
a
nd
hum
idit
y
s
ens
i
ng
pro
per
ti
es
of
t
he
synt
hesized
hem
at
i
te
nanoro
d
film
s
wer
e
e
xp
l
or
e
d.
T
he
hu
m
idit
y
sens
or
pe
rfor
m
ance
in
te
rm
s
of
sensi
ti
vity
, and
sta
bili
ty
ag
ai
ns
t t
he c
hanges
of
hum
idit
y l
evels
wer
e
also
pres
ented
i
n
this
work
.
2.
RESEA
R
CH MET
HO
D
Fabri
cat
ion
of
hem
atite
nan
oro
d
base
d
hu
m
idit
y
senso
r
require
a
fe
w
ste
p
s
involvi
ng
s
ubstrat
e
pr
e
par
at
io
n,
s
ol
ution
m
ixtur
e,
synthesis
pr
oc
ess,
a
nneal
in
g
treat
m
ent,
a
nd
ch
aracte
riz
at
ion
s.
T
he
α
-
Fe
2
O
3
nano
rod
a
rr
ay
s
with
nano
por
es
were
gro
w
n
on
flu
ori
ne
ti
n
oxi
de
(FTO
)
glass
s
ubstrat
e
in
a
Sc
hott
bo
tt
le
us
in
g
lo
w
-
te
m
per
at
ur
e
s
onic
a
te
d
so
l
–
gel
im
m
ersion
te
c
hn
i
qu
e
.
Gen
e
rall
y,
FT
O
glass
s
ubstrat
e
is
tra
nspare
nt,
wh
ic
h
has
a
c
onduct
ive
la
ye
r
(F
T
O
la
ye
r)
deposite
d.
Thi
s
cond
uctive
la
ye
r
was
us
e
d
as
a
su
rf
ace
t
o
g
row
hem
atite
la
ye
r
durin
g
im
m
ersion
process
.
Pri
or
to
t
he
synt
he
sis
of
hem
at
i
t
e
nano
rod
ar
ra
y
structu
re,
the
FT
O
su
bst
rate
was
cl
eaned
to
rem
ov
e
a
ny
con
ta
m
inati
on
s.
FT
O
substrat
es
w
it
h
the
di
m
ension
s
of
2
×
2cm
were
i
m
m
ersed
an
d
cl
eansed
in
a
be
aker
fill
ed
w
it
h
m
et
han
ol
(C
H
3
O
H).
The
n,
the
cl
eanin
g
pr
ocess
was
co
nducte
d
us
in
g
s
on
ic
at
io
n
pro
cess
in
a
n
ultraso
nic
cl
eanser
f
or
10
m
inu
te
s
at
50°C.
The
sam
e
cl
ea
ning
pr
ocedur
e
wa
s
rep
eat
e
d
by
re
placi
ng
m
et
ha
no
l
with
deio
ni
zed
(
DI
)
wate
r.
Af
te
r
t
his
pr
ocess,
t
he
FT
O
substrat
es
were
dr
ie
d
with
nitroge
n g
as
.
Hem
atite
nan
oro
d
ar
rays
we
re
synthesiz
e
d
throu
gh
s
onic
at
ed
so
l
–
gel
im
m
ersion
m
e
t
hod.
In
thi
s
proce
dure,
aq
ue
ous
so
luti
on
was
prepa
red
by
disso
l
ving
0.2
M
fer
ric
chlo
ride
(F
eC
l
3
⋅
6H
2
O),
an
d
0.2M
ur
e
a
(NH
2
CO
NH
2
)
in
bea
ke
r
fill
ed
with
DI
wate
r
.
T
he
s
olu
ti
on
was
s
onic
at
ed
in
ultras
onic
w
at
er
bat
h
at
50°C
f
or
30
m
inu
te
s,
a
nd
subse
quently
sti
rr
ed
unde
r
r
oo
m
tem
per
at
ur
e
on
a
sti
rr
e
r
f
or
5
m
inu
te
s
at
250
r
pm
.
The
n,
the
FTO
substrat
e
s
we
re
place
d
in
Sc
ho
tt
v
ia
l
with
the
co
n
duct
ive
surface
f
aci
ng
up.
T
he
so
luti
on
m
ixtur
e
w
a
s
poured
grad
ua
ll
y
into
the
S
cho
tt
bo
tt
le
s
.
The
n,
t
he
bo
tt
le
s
wer
e
seal
e
d
a
nd
im
m
ersed
in
to
a
wat
er
ba
th
equ
i
pm
ent
for
two
ho
ur
s
at
95°C.
A
fter
im
m
ersion
proce
s
s,
the
sam
ples
wer
e
ta
ke
n
out
from
the
bo
tt
le
s
an
d
dr
ie
d
f
or
10 m
i
nu
te
s at
150°
C
in
a f
urnace.
T
hen, the
sy
nth
e
siz
ed
hem
at
it
e
sam
ples w
ere an
neale
d
at
d
if
f
eren
t
tem
per
at
ur
es
of
350°
C,
40
0°C
,
45
0°
C,
500°
C, 55
0°
C, a
nd
600°
C
f
or
one
hour.
T
he
cryst
al
li
nity
pr
op
e
rtie
s
of
t
he
pre
par
e
d
hem
at
i
te
sa
m
ples
wer
e
in
vestigat
ed
us
ing
a
n
X
-
ray
diffracti
on
(
X
RD;
PANal
yt
ic
al
X'
Pert
PRO)
with
C
uK
α
rad
ia
ti
on
.
T
he
su
r
face
m
or
ph
ologies
of
the
sam
ples
wer
e
c
har
act
er
iz
ed
us
in
g
a
fiel
d
e
m
issi
on
scann
i
ng
el
ect
r
on
m
ic
ro
sco
py
(F
ESEM;
JE
OL
JSM
-
7600
F)
.
T
he
op
ti
cal
pro
per
t
ie
s
of
t
he
he
m
at
i
te
nan
or
od
ar
rays
wer
e
determ
in
ed
usi
ng
a
n
ultra
vio
le
t
–
visi
ble
(
UV
-
Vis
)
sp
ect
r
o
sc
op
y
(
Var
ia
n
Ca
ry
5000
).
F
or
the
dev
ic
e
c
ha
racteri
zat
ion
,
the
s
a
m
ples
wer
e
de
posit
ed
with
60
-
nm
-
thick
Plat
in
um
(P
t)
m
et
al
con
ta
ct
us
in
g
th
erm
al
evap
or
at
or.
The
physi
ca
l
m
ask
was
use
d
to
c
reate
m
et
al
con
ta
ct
patte
rns
on
t
he
sam
ple
duri
ng
eva
po
rati
on
pro
cess
.
The
hum
idity
sens
or
m
easur
e
m
ent
was
pe
rfor
m
ed
us
in
g
a
hum
idi
ty
ch
am
ber
(
E
SPEC
-
S
H
261)
equ
i
pp
e
d wit
h a sens
or m
easur
em
ent syst
e
m
(K
ei
thley
24
00)
.
Evaluation Warning : The document was created with Spire.PDF for Python.
Ind
on
esi
a
n
J
E
le
c Eng &
Co
m
p
Sci
IS
S
N:
25
02
-
4752
Impact
o
f
anne
aling t
em
per
atu
re t
o
the
p
erf
or
m
ance
of
he
ma
ti
te
…
(
Wa
n Ros
m
ar
ia
Wan A
hma
d
)
1081
3.
RESU
LT
S
AND A
N
ALYSIS
The
XRD
patte
rn
s
of
the
sy
nth
esi
ze
d
sam
ple
s
in
Fi
gure
1(
a
)
s
hows
t
ha
t
pure
hem
at
i
te
(α
-
Fe
2
O
3
)
ph
a
se
d
film
s
w
ere
gro
w
n
on
the
FT
O
s
ubstrat
e
s
.
The
oth
e
r
phases
of
ir
on
oxide
s
uch
as
m
egh
e
m
it
e
and
m
agn
et
it
e
were
not
at
ta
ined
i
n
the
synth
esi
zed
sam
ples
accor
ding
t
o
the
XRD
patte
r
n
s
.
The
dif
fr
act
io
n
pea
ks
at
26
˚
,
38˚,
a
nd
53˚
wit
h
high
intensit
y
corr
esp
ond
to
FT
O
la
ye
r
wer
e
al
so
rec
orded
in
t
he
XRD
patte
r
n
s
due
to
X
-
ray
pen
e
trat
ion
into
th
e
FTO
co
nduc
ti
ve
la
ye
r
on
the
glass
sub
strat
e.
The
ob
serv
e
d
pea
ks
f
or
the
hem
atite
nanorod
ar
rays
a
re
a
tt
ribu
te
d
to
a
poly
cryst
al
li
ne
structu
re
with
rhom
bo
he
dr
al
la
tt
ic
e
syst
e
m
unde
r
trigonal
cryst
al
syst
e
m
with
resp
ect
to
JCP
DS
#3
3
-
0664.
The
s
am
ples
ann
eal
e
d
at
high
te
m
per
at
ur
es
(500°C,
550°
C
,
a
nd
60
0°
C)
ha
ve
five
diffra
ct
io
n
pea
ks
i
n
the
ra
nge
betwee
n
20˚
t
o
90˚
,
w
hich
c
orres
pond
to
th
e
m
ain
or
ie
ntati
on
s
of
α
-
Fe
2
O
3
,
nam
e
ly
,
(1
04)
,
(
110),
(
214),
(
125),
and
(
128)
plan
es
.
H
ow
e
ver
,
the
sam
ples
anneal
ed
at
low
te
m
per
at
ur
es
(35
0°
C,
400°
C
,
an
d
450°
C)
sho
w
no
n
-
ap
pear
a
nce
of
the
dif
fr
act
io
n
peak
c
orres
po
nd
s
t
o
(11
0)
plane
ori
entat
ion
as
in
dicat
ed
in
Fi
g
ure
1(b
).
T
his
conditi
on
is
du
e
t
o
a
nat
ure
of
l
ow
-
an
ne
al
ing
-
tem
per
at
ur
e
pr
ocess, w
hich
has i
nsuf
fici
ent
heat ene
r
gy for a com
plete
crysta
ll
iz
ation
pro
cess.
(a)
(b)
Figure
1
.
(a
)
T
he
XRD patt
er
n
s
of h
em
at
it
e
nano
rod
a
rr
ay
s
at
dif
fer
e
nt a
nneal
ing t
em
per
at
ur
e.
(
b)
T
he
diffracti
on
pea
ks
i
n
the
r
a
ng
e
betwee
n
22
⁰
-
27
⁰
s
howi
ng the
appeara
nce
of
(11
0)
plane
ori
entat
ion
pea
k f
or
sam
ples an
ne
al
ed
at
500°
C
, 5
50°C, a
nd
600°C
Figure
2.
FES
EM im
ages of α
-
Fe
2
O
3
na
nor
od ar
rays at
dif
fer
e
nt anneal
in
g
te
m
per
at
ur
e
of (
a
) 350°C,
(b)
400°
C
, (
c
) 4
50°C, (d
) 500°C,
(e)
550°C
, a
nd
(f)
600°
C at
50
,000
×
m
agn
ific
at
ion
Evaluation Warning : The document was created with Spire.PDF for Python.
IS
S
N
:
2502
-
4752
Ind
on
esi
a
n
J
E
le
c Eng &
Co
m
p
Sci,
Vo
l.
1
3
, N
o.
3
,
Ma
rc
h
201
9
:
1079
–
1
0
8
6
1082
The
F
ESEM
i
m
ages
in
Fi
gure
2
de
pict
the
surface
m
orp
ho
l
og
ie
s
of
the
pr
e
pa
red
hem
at
it
e
nan
or
od
arr
ay
sam
ples
at
dif
fere
nt
ann
eal
in
g
te
m
per
at
ur
es
ta
ke
n
at
50,
000
×
m
agn
ific
at
ion
.
From
the
su
r
face
m
or
phology
im
ages,
al
l
sam
ples
e
xh
i
bit
na
nor
od
str
uctu
re
s,
wh
ic
h
gro
w
n
perpe
nd
ic
ula
r
to
the
substra
te
s
.
F
or
the
sam
ples
an
nealed
at
te
m
per
at
ur
e
hi
gher
than
500˚C,
la
r
ge
pore
a
reas
a
re
ob
se
r
ved
be
tween
t
he
nano
rods
.
These
sam
ples
al
so
ex
hib
it
hi
gh
por
ous
str
uc
tures
.
The
for
m
at
ion
of
pore
areas
bet
ween
the
na
nor
od
s
m
igh
t
be
due
to
t
he
evap
orat
ion
of
im
pu
riti
es
durin
g
the
a
nneal
ing
t
reatm
ent
an
d
the
m
erg
i
ng
act
ivit
y
of
th
e
nano
rods
at
hi
gh
te
m
per
at
ur
e
.
The
ave
ra
ge
diam
e
te
rs
of
hem
at
it
e
nan
oro
d
an
nealed
at
diff
e
re
nt
tem
per
at
ure
s
are
li
ste
d
in
th
e
Table
1
.
T
he
ta
ble
show
s
that
the
a
ver
a
ge
di
am
et
er
sizes
of
hem
at
it
e
nano
rods
a
r
e
r
ang
i
ng
from
5
0 nm
to
80 n
m
.
The
op
ti
cal
pro
per
ti
es
of
hem
at
it
e
nan
orod
sam
ples
at
dif
fer
e
nt
an
ne
al
ing
te
m
per
at
ur
e
were
determ
ined
fro
m
the
UV
–
vis
transm
ittance
sp
ect
r
a
in
the
ra
ng
e
of
300
–
80
0
nm
,
as
ind
ic
at
ed
in
Fig
u
re
3(a).
It
is
ob
se
r
ved
th
at
al
l
sa
m
ples
exh
i
bit
high
tr
ansm
issi
on
gre
at
er
than
80%
in
the
wav
el
e
ngth
reg
i
ons
bet
ween
600
to
800
nm.
The
s
pectra
r
eveal
that
t
he
s
a
m
ples
ann
eal
ed
at
lowe
r
te
m
per
at
ur
e
ha
ve
higher
tra
nsm
ittance
pro
per
ti
es.
It
a
lso
can
be
perc
ei
ved
that
the
sa
m
ple
a
nn
eal
ed
at
550°
C
ha
s
the
lowest
transm
it
ta
nce
values
.
The
hi
gh
tra
nsm
ittance
prope
rtie
s
m
igh
t
be
at
tribu
t
ed
to
t
he
s
m
al
le
r
nan
ost
ru
ct
ure
siz
e
wh
ic
h
le
ads
to
hig
he
r
por
os
it
y
in
the
hem
atite
na
nor
od
s
fil
m
s
.
Th
us
,
it
reduc
es
the
op
ti
cal
scat
te
ring
ef
f
ect
and
en
ha
nc
es
the
transm
issi
on
of
the
li
gh
ts
thr
ough
the
sam
ple.
Fr
om
the
transm
ittance
spe
ct
ra,
the
abs
orptio
n
coe
ff
ic
i
ents
of
thin
fil
m
s w
ere
calc
ulate
d usi
ng Lam
ber
t’s l
aw
as
sho
wn in
(1)
:
T
t
1
ln
1
(1)
wh
e
re
t
is
the
nanostr
uctu
re’s
fil
m
thicknes
s
wh
ic
h
wa
s
e
stim
at
ed
fr
om
cro
ss
-
sect
io
nal
i
m
ages
and
T
is
the
m
easur
ed
t
ran
s
m
ittance.
Fig
ure
3(b)
d
e
picts
the
abs
orptio
n
c
oeffici
ent
sp
ec
tra
of
t
he
hem
at
it
e
fil
m
s.
Fr
om
the
abs
orption
c
oe
ff
ic
ie
nt
s
pectra
,
t
he
he
m
at
it
e
nano
rod
sam
ple
ann
eal
e
d
at
high
te
m
per
a
ture
ex
hib
it
s
hi
gh
U
V
abs
orption p
r
operti
es at
wave
le
ng
th
s
belo
w 600
nm
.
Figure
4
s
how
s
Tauc’s
pl
ot
of
the
hem
at
ite
nanoro
d
ar
ra
ys
der
ive
d
us
ing
(2)
.
T
he
e
qu
at
io
n
for
op
ti
cal
ban
d ga
p
e
nergy est
im
at
ion
is s
how
n
(2)
:
g
E
hv
A
ahv
2
(2)
H
ere
,
α
,
hv,
A
,
an
d
E
g
repres
ent
the
a
bsor
ption
c
oeffici
ent,
photon
e
nerg
y,
const
ant,
a
nd
ba
nd
ga
p
energy,
res
pec
ti
vely
.
The
ba
nd
ga
p
ene
rgy
of
the
hem
at
it
e
nan
oro
d
arr
ay
s
we
re
de
te
rm
ined
f
rom
the
extra
po
la
ti
on
of
the
li
near
si
de
of
the
grap
h
.
The
est
im
a
te
d
op
ti
cal
ba
nd
ga
p
val
ues
of
th
e
sa
m
ples
are
in
th
e
ranges
betwee
n 2.1 e
V
to
2.2 eV,
which
con
sist
ent w
it
h
t
he
r
e
ported val
ue
s in
li
te
ratu
re
[
22
]
.
(a)
(b)
Fig
ure
3.
O
ptica
l pro
per
ti
es
of h
em
at
it
e n
anorod a
rr
ay
fil
m
sam
ples
at
different a
nneal
ing t
e
m
per
at
ures:
(a)
transm
ittance a
nd (b) ab
sorpti
on co
e
ff
ic
ie
nt
sp
ect
ra
Evaluation Warning : The document was created with Spire.PDF for Python.
Ind
on
esi
a
n
J
E
le
c Eng &
Co
m
p
Sci
IS
S
N:
25
02
-
4752
Impact
o
f
anne
aling t
em
per
atu
re t
o
the
p
erf
or
m
ance
of
he
ma
ti
te
…
(
Wa
n Ros
m
ar
ia
Wan A
hma
d
)
1083
Fig
ure
4.
Esti
m
at
ion
of the
opti
cal
b
a
nd g
a
p ene
rg
y
(E
g
)
u
s
ing
Tauc'
s p
l
ot
Table
1
.
A
ver
a
ge diam
et
er an
d hu
m
idit
y sensing sensiti
vity
of
hem
atite
n
anor
od ar
rays pr
epar
e
d
at
d
if
fere
nt
ann
eal
in
g
te
m
per
at
ur
e
s
An
n
ealin
g
T
e
m
p
er
atu
re
Av
erage Dia
m
ete
r
(n
m
)
Sen
sitiv
ity
(40
-
9
0
)
%R
H
3
5
0
°C
55
2
2
.41
4
0
0
°C
80
1
7
7
.78
4
5
0
°C
76
3
9
.40
5
0
0
°C
62
1
1
9
.33
5
5
0
°C
66
2
9
.77
6
0
0
°C
64
5
.51
The
perform
ance
of
the
fabrica
te
d
hem
at
it
e
hu
m
idit
y
sensors
wa
s
m
easur
ed
th
rou
gh
the
var
ia
ti
on
of
hu
m
idit
y
con
di
ti
on
s
.
The
a
bso
rp
ti
on
process
(r
es
pons
e
)
was
m
easur
e
d
f
or
r
el
at
ive
hu
m
idity
ranges
f
r
om
40%
to
90%
RH
,
w
hile
the
desorpt
ion
proces
s
(rec
ov
e
ry)
wa
s
m
easur
e
in
the
ranges
betwe
en
90
%
to
40
%
RH
.
The
hum
idit
y
respo
ns
e
an
d
recovery
r
oute
wer
e
m
easur
ed
in
hum
idity
cha
m
ber
wi
th
5V
bias
at
room
tem
per
at
ur
e (25°
C)
.
It
ca
n
be
unde
rstood
fro
m
the
p
lott
ed
grap
h
in Fig
ure
5
(a
)
that
al
l
sa
m
ples
exh
ibit
a
good
hu
m
idit
y
resp
on
s
e
with
ra
pi
d
cha
ng
e
s
of
current
sig
nal
as
the
hu
m
idity
le
vel
increases
from
40
%RH
t
o
90%RH,
a
nd
prom
ptly
decay
s
as
the
hum
idit
y
le
vel
i
s
ram
p
ed
dow
n
f
ro
m
90
%
RH
to
40%
R
H.
T
he
sens
it
ivit
y, S, of t
he
se
nsor
was est
i
m
at
ed
usi
ng
t
he follo
wi
ng
(
3
)
:
rh
a
R
R
S
(3)
wh
e
re
R
a
an
d
R
rh
is
the
r
esi
sta
nce
of
the
se
nsor
ex
posed
to
the
init
ia
l
hum
idit
y
le
vel
(40
%RH)
a
nd
m
axim
u
m
hu
m
idit
y
le
vel
(90%RH
),
res
pecti
vely
.
The
resist
ance
val
ues
we
re
at
ta
ined
from
the
current
va
lues
of
the
respo
ns
e
cu
rv
e
s
us
in
g
O
hm
’s
la
w
(V
=
IR).
T
able
1
prese
nts
the
sensiti
vity
,
S
cal
culat
ed
f
or
al
l
sam
ples.
It
ca
n
be
per
c
ei
ve
d
th
at
the sa
m
ple a
nn
eal
e
d
at
4
00
°C
has
the
highest
sensiti
v
it
y value o
f 177.
78, follow
s
by sa
m
ple
ann
eal
e
d
at
500
°C
with
S
=
119.3
3.
The
s
a
m
ple
ann
eal
ed
at
60
0°C
is
fou
nd
to
be
th
e
le
ast
sensit
ive
to
hu
m
idit
y
with
sensiti
vity
value
of
5.51.
T
he
high
se
ns
it
ivit
y
value
obta
ined
f
or
the
s
e
sa
m
ples
is
m
ai
nly
at
tribu
te
d
to
na
nopores
,
w
hich
form
ed
betw
een
α
-
Fe
2
O
3
a
ggre
gates
and
facil
it
at
e
hig
h
su
r
face
area
f
or
water
m
olecules to d
i
ffuse ac
ross th
e sam
p
le
.
The
hum
idit
y
sensor
m
eas
ur
em
ent
(r
es
pond
a
nd
recovery)
wer
e
re
peated
f
or
a
f
ew
cy
cl
es
to
m
easur
e
the
st
abili
ty
of
the
sens
or
detect
ion.
Fig
ure
5
(
b
)
il
lustrate
s
th
e
rep
eat
a
bili
ty
current
res
po
ns
e
to
diff
e
re
nt
hu
m
i
dity
le
vel
fo
r
s
a
m
ple
ann
eal
e
d
at
400°
C
.
Th
e
sensor
m
eas
ur
em
ent
resu
lt
s
dem
on
strat
e
a
go
od
sta
bili
ty
resp
onse,
with
al
m
os
t
identic
al
curves
ob
se
r
ved
over
five
cy
cl
es
.
Fig
ure
5
(
c
)
il
lustrate
s
the
c
urren
t
respo
ns
es
of
sa
m
ple
ann
eal
ed
at
400°C
to
di
f
fer
e
nt
hu
m
idity
le
vels.
T
he
pl
ot
sho
ws
t
hat
the
sam
ple
res
pons
e
well
with
the
diff
e
re
nt
hum
i
dity
le
vels.
Fig
ure
5
(
d
)
s
ho
ws
the
se
ns
it
iv
it
y
values
of
t
he
sam
ples
at
diff
e
re
nt
hu
m
idit
y l
evel
s.
The
grap
h re
veals
that t
he
s
a
m
ple an
neale
d
at
40
0°
C
e
xhibit
s
the
hi
gh
es
t sensit
ivit
y valu
es a
t
var
i
ou
s
hum
idi
ty
levels
.
Evaluation Warning : The document was created with Spire.PDF for Python.
IS
S
N
:
2502
-
4752
Ind
on
esi
a
n
J
E
le
c Eng &
Co
m
p
Sci,
Vo
l.
1
3
, N
o.
3
,
Ma
rc
h
201
9
:
1079
–
1
0
8
6
1084
(a)
(b)
(c)
(d)
Fig
ure
5.
(a
)
H
um
idity sensor
r
es
pons
es
of
hem
at
it
e n
ano
r
od
a
rr
ay
-
base
d hu
m
idit
y sensor
s
at
diff
e
re
nt
ann
eal
in
g
te
m
per
at
ur
e
s
. (b
)
R
epeata
bili
ty
h
um
idit
y resp
ons
e of f
a
bri
cat
ed hem
atite
h
um
i
dity
sens
or an
ne
al
ed
at
4
00°C
, (
c
)
C
urren
t
res
pons
e
s of sam
ple 40
0°
C t
o diff
e
rent
h
um
idit
y (
d
)
Sens
it
ivit
y plot
of sam
ples
at
diff
e
re
nt hum
i
dity
level
s
The
ge
ner
at
e
d
cu
rr
e
nt
at
hi
gh
hu
m
idit
y
l
evel
ca
n
be
e
xp
la
ine
d
by
t
he
fact
that
the
el
ect
r
olyt
ic
cond
uction
s
oc
cur
in
the
sam
ple.
H
i
gh
den
s
it
y
of
water
m
olecules
at
high
hum
idit
y
le
vel
pr
om
otes
proto
n
hoppin
g
insi
de
the
film
s,
wh
ic
h
occ
urs
al
on
g
a
series
of
hy
drog
e
n
bonds
betwee
n
hydron
i
um
ion
s
an
d
wate
r
m
olecules.
When
the
s
urface
area
of
hem
at
ite
nanoro
d
inc
r
ease
s
,
the
rate
of
water
a
ds
or
ption
on
the
s
urface
i
m
pr
oves
at
the
increased
hum
idit
y
le
vel.
Con
se
quently
,
the
el
ect
rical
pr
operti
es
of
th
e
dev
ic
es
cha
nge
an
d
even
t
ually
cause
the
el
ect
ro
ly
ti
c
con
duct
io
n
in
the
film
s
.
T
he
hem
at
it
e
na
nor
od
a
rr
ay
s
ha
ve
hi
gh
s
urfa
ce
are
a
du
e
t
o
the
na
nor
od
s
truct
ur
e
it
sel
f
and
the
f
or
m
at
ion
of
na
nopores
on
t
he
nanoro
d
surfa
ce.
Th
us
,
it
can
be
exp
ect
e
d
that
the
water
a
dsor
ption
unde
r
va
rio
us
hum
idit
y
le
vel
of
hem
a
ti
te
nan
oro
d
ar
ray
s
are
bette
r
tha
n
that o
f
the
con
ven
ti
onal
na
no
structu
res suc
h as
nano
par
ti
cl
es an
d na
no
c
ubes.
4.
CONCL
US
I
O
N
Hem
atite
(α
-
Fe
2
O
3
)
na
nor
od
arr
ay
s
we
re
suc
cessf
ully
pr
ep
ared
via
so
nica
te
d
i
m
m
ersion
m
et
ho
d
on
FTO
c
oated
gl
ass
substrat
es
at
diff
e
ren
t
a
nneal
ing
te
m
perat
ur
e
s
rangin
g
from
35
0
⁰
C
t
o
60
0
⁰
C
.
T
he
XRD
patte
rn
re
veale
d
that
α
-
Fe
2
O
3
ex
hib
it
s
a
rhom
bo
he
dr
al
st
ru
ct
ur
e
with
fi
ve
diffracti
on
peaks
c
orrespo
nd
to
(10
4)
,
(11
0),
(21
4)
,
(12
5),
and
(
128)
pla
ne
ori
entat
io
ns
.
Dif
fr
act
io
n
peak
c
orres
pond
to
(11
0)
plane
or
ie
ntati
on
ap
pe
ars
f
or
sam
ples
ann
eal
e
d
at
500˚
C
and
a
bove
.
Hem
at
it
e
nan
or
od
sam
ples
exh
i
bits
a
unifor
m
grow
t
h
an
d
sm
al
l
dia
m
et
er
si
ze
rangin
g
fro
m
55
nm
to
80
nm
.
The
op
ti
cal
ban
d
gap
of
hem
a
ti
te
ann
e
al
ed
at
diff
e
re
nt
tem
per
at
ur
e
s
range
s
fr
om
2.
1
eV
to
2.
2
eV
.
Th
e
hig
hest
se
ns
it
ivit
y
was
reco
r
de
d
for
th
e
sam
ple
ann
eal
e
d
at
40
0°C
with
the
value
of
177.7
8
w
hen
the
hu
m
idit
y
chan
ge
s
from
40
%
RH
to
90%
RH
.
Evaluation Warning : The document was created with Spire.PDF for Python.
Ind
on
esi
a
n
J
E
le
c Eng &
Co
m
p
Sci
IS
S
N:
25
02
-
4752
Impact
o
f
anne
aling t
em
per
atu
re t
o
the
p
erf
or
m
ance
of
he
ma
ti
te
…
(
Wa
n Ros
m
ar
ia
Wan A
hma
d
)
1085
The
hu
m
idit
y
response
f
or
hem
atite
nan
oro
d
ar
ray
-
base
d
sens
ors
al
so
exh
i
bit
a
good
rep
eat
a
bili
ty
and
sta
bili
ty
ov
er
fi
ve
cy
cl
es.
ACKN
OWLE
DGE
MENTS
Th
is
w
ork
was
su
pport
ed
by
REI
gr
a
nt
(
600
-
IRMI/R
EI
5/3
(0
17/2
018))
.
The
aut
hors
w
ou
l
d
li
ke
to
ackno
wled
ge
t
he
I
ns
ti
tute
of
Re
searc
h
M
anag
em
ent
an
d
I
nnovat
io
n
(I
RM
I
)
a
nd
F
acult
y
of
Ele
ct
rical
En
gin
eeri
ng
of U
iTM
for
thei
r
s
upport
of thi
s r
esea
rch.
REFERE
NCE
S
[1]
A.
Tri
pa
th
y
,
S.
Pram
ani
k,
A.
Manna
,
S.
Bhu
y
a
n
,
N.
F.
Azri
n
Shah,
Z
.
Radzi,
a
nd
N.
A.
Abu
Os
m
an,
"
Sign
and
Deve
lopment
fo
r
Capa
c
it
iv
e
Hum
idi
t
y
Sensor
Applic
a
ti
ons
of
Le
ad
-
Fre
e
Ca
,
Mg,
Fe,
Ti
-
Oxi
des
-
Based
Elec
t
ro
-
Cera
m
ic
s with
I
m
prove
d
Sensing
Properties
vi
a P
h
y
sisorption,
"
Sensors
,
vol. 16, pp. 1135, 2016.
[2]
I.
Rahi
m
,
M.
Shah,
A.
Khan,
A.
Zhong,
M.
Li,
R.
Ahm
ed,
H.
Li
,
Q.
W
ei
,
Y.
Fu,
M.
Shah,
A.
Khan,
A.
Zhong,
M
.
Li
,
R
.
Ahm
ed,
H.
Li,
Q.
W
ei,
and
Y.
Fu,
"
Capa
c
itive
and
r
esisti
ve
response
of
hum
idi
t
y
sensors
base
d
on
gra
phen
e
dec
ora
te
d
b
y
P
MM
A a
nd
silve
r
nanopa
r
ti
c
le
s,
"
Sensors
and
Ac
t
uators B
:
Chemi
cal
,
vol
.
267
,
pp
.
42
-
50,
2018.
[3]
B.
Yada
v,
A.
K.
Srivasta
va,
and
P.
Sharm
a,
"
Resista
nce
Based
Hum
idi
t
y
Sensi
ng
Properti
es
of
Ti
O
2
,
"
Sensor
s
&
Tr
ansduce
r
s J
ournal
,
vol
.
81
,
pp
.
1348
–
1353,
200
7.
[4]
A.
S.
Is
m
ai
l,
M.
H.
Mam
at
,
N.
D.
Md.
Sin,
M.
F.
Male
k,
A.
S
.
Zool
fak
ar,
A.
B.
Suriani
,
A.
Moham
ed,
M.
K.
Ahm
ad,
and
M.
Rusop,
"
Fabric
a
ti
on
of
Hier
ar
ch
ic
a
l
Sn
-
doped
Z
nO
Nanorod
Arr
a
y
s
Through
So
nic
a
te
d
Sol−Ge
l
Im
m
ersi
on
for
R
oom
Te
m
per
at
ure
,
Resisti
v
e
-
T
y
p
e
Hum
idi
t
y
Sens
or
Applic
ations
,
"
Ceramic
Inte
rnational
,
vo
l.
42
,
pp.
9785
-
9795
,
2016.
[5]
J.
M.
Tulli
ani
an
d
P.
Bonvil
le
,
"
I
nflue
nc
e
of
the
Dopants
on
the
El
e
ct
ri
ca
l
Resist
anc
e
of
Hem
at
i
t
e
-
Based
Hum
idit
y
Sensors
,
"
Ceramic
In
te
rnationa
l
,
vol.
31
,
pp
.
507
–
514,
2005
.
[6]
K.
J.
Park
and
M.
S.
Gong,
"
A
W
at
er
Durabl
e
R
esisti
ve
Hum
idi
t
y
Sen
sor
Based
on
Rigi
d
Sulfonate
d
Pol
y
ben
zi
m
idaz
ole
and The
ir
Pr
oper
ties
,
"
Sensor
s and
Actuators
B:
Chemi
cal
,
vol
.
246
,
pp
.
53
–
60
,
2017.
[
7]
Z.
Chen
and
C
.
Lu,
"
Hum
idi
t
y
Sensors
:
A
Revi
ew
of
Mat
eri
a
ls
and
Mec
hani
sm
s,
"
Senso
r
Lett
ers
,
vol.
3,
pp.
274
–
295
,
20
05.
[8]
P.
-
G.
Su
and
L.
-
N.
Huang,
"
Hum
idi
t
y
Sensors
Based
on
Ti
o
2
Nanopa
rticle
s/P
ol
y
p
y
rro
le
Com
posite
Thi
n
Fil
m
s
,
"
Sensors
and
Ac
t
uators
B:
Chemi
cal
,
vol
.
123
,
pp
.
501
–
507,
2007.
[9]
M.
Parthi
bav
ar
m
an,
V.
Hari
har
an,
and
C
.
Seka
r,
"
High
-
sensiti
v
ity
Hum
idi
t
y
Se
nsor
Based
on
Sno
2
Nanopa
rticl
es
S
y
nthe
si
ze
d
b
y
Microwa
ve
Ir
rad
iation
Me
th
od
,
"
Mate
ria
ls
Scienc
e
and
Engi
n
ee
ring:
C
,
vol
.
31
,
(
5
)
,
p
p.
840
–
844
,
20
11.
[10]
G.
Neri
,
a
.
Bon
avi
t
a,
S.
Galv
ag
no,
N.
Donato,
and
a.
Cadd
emi,
"
El
ectrical
Cha
rac
t
eri
z
ation
of
Fe
2
o
3
Hum
idi
t
y
Sensors
Doped
with
L
i
+
,
Zn
2+
an
d
Au
3+
Ions
,
"
S
e
nsor
s and
Ac
tuator
s B
:
Chemi
cal
,
vol. 111
–
112,
p
p.
71
–
77
,
2005
.
[11]
Z.
Cao,
M.
Qin,
Y.
Gu,
B.
Jia,
P.
Chen,
and
X.
Qu,
"
Sy
nth
esis
and
Chara
cteri
za
t
ion
of
Sn
-
Do
ped
Hem
at
it
e
a
s
Visible
Li
ght
Photocataly
st
,
”
Ma
te
rials
Re
search
Bul
letin
,
vol
.
77
,
pp.
41
–
47,
2016
.
[12]
C.
W
u,
P.
Yin,
X.
Zhu
,
C.
OuY
ang,
and
Y.
Xie
,
"
S
y
n
the
sis
of
Hem
at
it
e
(Alpha
-
Fe
2
o
3
)
Nanorod
s:
Diamete
r
-
Si
ze
a
nd
Shape
Eff
e
ct
s
o
n
The
ir
Applicati
ons
i
n
Ma
gnet
ism
,
Li
th
iu
m
Ion
Bat
te
r
y
,
a
nd
Gas
Sensor
s
,
The
Journal
of
Phy
sica
l
Chemis
try
B
,
vo
l. 110, p
p.
17806
–
12
,
20
06.
[13]
A.
Subram
ani
an
,
E.
Gra
cia
-
Espi
no,
A.
Annam
al
ai
,
H.
H.
Lee,
S
.
Y.
Lee,
S.
H.
Choi,
and
J.
S.
Jang,
"
Eff
e
ct
of
Te
tr
ava
l
ent
Dop
ant
s
on
Hem
atit
e
Nanostruc
ture
for
Enh
anced
Photoel
e
ct
roc
h
e
m
ic
al
W
ater
Sp
li
tting
,
"
Applie
d
Surface
S
ci
en
ce
,
vol. 427, pp. 12
03
–
1212,
2018
.
[14]
A.
La
ss
oued
,
M
.
S.
La
ss
oued,
B
.
Dkhil
,
S.
Am
m
ar,
and
A
.
Ga
dri,
"
S
y
nthe
sis,
Struct
ura
l,
Morp
hologi
c
al
,
Optical
And
Magne
ti
c
C
har
acte
ri
zation
o
f
Iron
Oxide
(Α
-
Fe
2
o
3
)
Nanopa
rticle
s
b
y
Pr
ec
ip
it
a
ti
on
Method:
Ef
f
ec
t
o
f
Var
y
ing
t
he
Na
ture
o
f
Pr
ec
ursor
,
"
Ph
ysica
E:
Low
-
dimen
sional
Syst
ems and
Nanostr
uct
ures
,
vol
.
97
,
pp
.
3
28
–
334,
2018
.
[15]
M.
Bal
ogun,
Z.
W
u,
Y.
Luo,
W
.
Qiu,
X.
Fan,
B.
Long,
M.
Hu
ang,
P.
L
iu,
and
Y.
Tong,
"
Hig
h
Pow
er
Densit
y
Nitri
dated
Hem
a
ti
te
(Α
-
Fe
2
o
3
)
N
anor
ods
a
s
Anod
e
f
or
High
-
Perfo
rm
anc
e
Fl
ex
ibl
e
Li
thi
um
Ion
Batt
eri
es
,
"
Journal
of
Pow
er
Source
s
,
vol. 308, pp. 7
–
17,
2016
.
[16]
Y.
W
.
Phuan,
M.
N.
Chong
,
T.
Zhu,
S.
T
.
Yong,
and
E.
S.
Chan
,
"
Eff
ects
of
Annea
li
ng
Te
m
per
at
ur
e
on
t
h
e
Ph
y
sicoc
h
emical
,
Optical
a
nd
P
hotoe
l
ec
tro
che
m
ic
a
l
Properties
o
f
Nanostruc
tured
Hem
at
it
e
Th
i
n
Film
s
Prepa
red
Via
E
le
c
trode
po
siti
on
Met
hod
,
"
Mate
rials
Re
sea
rch
Bulletin
,
vol
.
69,
pp.
71
–
77,
2
015.
[17]
A.
La
ss
oued
,
M
.
S.
La
ss
oued,
B
.
Dkhil
,
S.
Am
m
ar,
and
A
.
Ga
dri,
"
S
y
nthe
sis,
Struct
ura
l,
Morp
hologi
c
al
,
Optical
and
Magne
t
ic
C
har
acte
ri
zation
o
f
Iron
Oxide
(Α
-
Fe
2
o
3
)
Nanopa
rt
ic
l
es
b
y
Pre
ci
pi
t
at
ion
Me
thod:
E
ffe
ct
of
V
ar
y
ing
the
Na
ture of
Pr
ec
ursor
,
Phy
si
ca
E:
Low
-
dimensi
onal
Syst
ems and
Nanostr
uct
ure
s
,
vol. 97, pp. 32
8
–
334,
2018
.
[18]
K.
Bindu,
K.
M.
Ajit
h,
and
H.
S.
Naga
raja
,
"
Elec
tri
c
al
,
Di
el
e
ct
r
ic
a
nd
Magne
tic
Properties
o
f
Sn
-
Doped
Hem
at
it
e
(A
-
Sn
x
fe
2
-
X
o
3
)
Nanopla
t
es
S
y
nt
hesiz
ed
b
y
Mi
cr
owave
-
As
sisted
Method
,
"
Journ
al
of
A
ll
oys
and
Compounds
,
vol.
735,
pp
.
847
–
85
4,
2018
.
[19]
J.
Li
n,
X.
Zha
ng
,
L.
Zhou,
S.
Li
,
and
G.
Qin,
"
Pt
-
doped
α
-
Fe
2
O
3
Photoanode
s
Prepa
red
b
y
A
Mag
net
ron
Sputte
r
in
g
Method
for
Phot
oel
e
ct
roc
h
emical
W
at
er
Spli
tt
ing
,
"
Mat
erial
s R
ese
arch
Bu
ll
e
ti
n
,
v
ol.
91
,
pp
.
214
–
2
19,
2017
.
[20]
L.
Li,
C.
L
iu,
Y.
Qiu,
N.
Mi
tsuza
k,
and
Z
.
C
hen,
"
The
In
flu
enc
e
of
t
he
H
ydrothe
rm
al
Te
m
per
at
ur
e
a
nd
T
i
m
e
o
n
Morpholog
y
and
Photoelect
r
oche
m
ic
a
l
Resp
onse
o
f
Α
-
Fe
2
o
3
Photoanode
,
"
J
ournal
of
Al
lo
ys
and
Compounds
,
vol.
696
,
pp
.
980
–
987,
2017
.
Evaluation Warning : The document was created with Spire.PDF for Python.
IS
S
N
:
2502
-
4752
Ind
on
esi
a
n
J
E
le
c Eng &
Co
m
p
Sci,
Vo
l.
1
3
, N
o.
3
,
Ma
rc
h
201
9
:
1079
–
1
0
8
6
1086
[21]
C.
Colom
bo,
G.
Palumbo,
E.
Di
Iorio,
X.
Song,
Z.
Jiang
,
Q.
L
i
u,
and
R.
Ang
elico,
"
Influ
en
c
e
of
H
y
droth
ermal
S
y
nthe
sis
Condi
ti
ons
o
n
Siz
e,
M
orpholog
y
a
nd
Coll
oidal
Proper
ti
es
o
f
Hem
a
ti
t
e
Nanopa
rt
ic
l
es
,
"
Nano
-
Struct
ure
s
and
Nano
-
Objects
,
vol
.
2
,
pp
.
19
–
27,
2015
.
[22]
Q.
Meng,
Z
.
W
a
ng,
X.
Chai,
Z.
W
eng,
R.
Ding,
and
L
.
Dong,
"
Fabricat
ion
of
He
m
at
it
e
(Α
-
Fe
2
o
3
)
Nanopa
rt
ic
l
es
Us
ing
El
e
ct
ro
ch
emica
l
Depositi
o
n
,
"
Applied
Surf
ace
S
cienc
e
,
vo
l. 368, pp. 303
–
30
8,
2016
.
BIOGR
AP
HI
ES OF
A
UTH
ORS
W
.
R.
W
.
Ah
m
ad
rec
e
ive
d
B
Eng
(Hons
.
)
in
Microele
c
tronics
Engi
n
ee
ring
from
Univer
siti
Keba
ngsaa
n
Ma
lay
s
ia.
She
re
ceive
d
her
MS
c
i
n
Microe
ngin
eering
and
Nanoe
le
c
troni
cs
a
lso
from
Univer
siti
Keba
ngsaa
n
Ma
lay
s
ia.
She
is
cu
rre
ntly
a
le
c
ture
r
and
PhD
ca
ndida
te
in
Faku
lt
i
Kejur
ute
r
aa
n
Elektri
k
,
Univer
sit
i
Te
knologi
MA
RA,
Malay
si
a.
Her
cur
ren
t
rese
arc
h
inte
rests
ar
e
Nanote
chno
log
y
and
N
anoe
l
ec
t
r
onic
s.
M
.
H.
Mam
at
rec
e
ive
d
h
is
Bac
he
lor
degr
ee
in
Elec
tri
c
al
&
Elec
tron
ic
E
ngine
er
ing
and
Inform
at
ion
En
gine
er
ing
from
Nago
y
a
Univer
s
ity
,
Jap
an
and
both
of
his
Ph.
D.
and
Master
degr
ee
s
in
E
lectr
ic
a
l
Engi
n
ee
ring
from
Univer
siti
Te
knologi
MA
R
A,
Malay
sia
.
He
is
cur
ren
tly
a
Senior
Le
ct
u
rer
and
Hea
d
of
NANO
-
El
ec
Tron
ic
Cent
re
(NET
)
,
Facult
y
of
Elec
trica
l
Engi
n
ee
r
ing
at
Univer
siti
T
e
knologi
MA
RA.
His
rese
arc
h
intere
sts
ran
ge
ove
r
m
et
al
oxide
sem
ic
onduct
ors,
and
nanod
evice
s
.
Z.
Khus
ai
m
i
cur
ren
tly
holds
the
positi
on
of
a
S
eni
or
Lectu
re
r
a
t
the
School
of
Chemistr
y
and
Envi
ronm
ent
,
Fa
cul
t
y
of
Applie
d
Scie
nce.
She
is
an
associa
te
m
ember
of
the
Nan
oScie
nc
e
and
Nanote
chno
log
y
Center
(NanoS
ci
T
ec
h
)
,
Insti
tute
of
Sc
ie
nc
e,
UiTM.
She
ob
t
ai
ns
her
BS
c
.
(
Hons
)
from
U
nive
rsit
y
of
Ab
erd
ee
n
,
Scotlan
d,
Unite
d
King
dom
in
1993,
MS
C
(Anal
y
tica
l
Chemistr
y
)
from
Univer
sit
i
of
Malay
a
,
Kuala
Lu
m
pur
in
2002.
She
suce
ss
fully
o
bta
in
ed
her
PhD
in
2012
at UiT
M
.
Her
rese
arc
h
in
te
rests
are na
nos
ci
en
ce a
nd
n
anotec
hnolog
y
.
A.
S.
Ism
ai
l
recei
ved
his
Bac
h
elor
and
Master
degr
ee
in
El
e
ct
ri
c
al
Engi
n
ee
ring
f
rom
Univer
siti
Te
knologi
MA
R
A.
He
is
cur
ren
t
l
y
pursuing
his
Ph.D.
at
Univ
ersiti
Te
knolog
i
MA
RA,
Malay
s
ia
where
h
e
is wor
king
on
f
abr
i
ca
t
i
on
of
m
etal
ox
id
e
nanose
nsors
us
ing
soluti
on
-
bas
ed
m
et
hod
.
M.
Rusop
rec
ei
v
ed
his
Bac
he
lor
in
Engi
ne
eri
ng
f
rom
Nagoy
a
Uni
ver
sit
y
,
Jap
an.
H
e
recei
ved
h
is
Master
and
Ph.
D
in
Engi
nee
r
in
g
(Opto
-
El
e
ct
ron
ic
and
Nano
-
T
echnolog
y
)
from
Nago
y
a
Instit
u
te
of
Technol
og
y
,
Japa
n.
H
e
is
cur
ren
tly
Prof
essor
in
Faku
lt
i
Keju
rute
ra
an
El
ek
trik
and
He
ad
of
NANO
-
SciT
ec
h
(NS
T)
Cent
re,
Instit
ute
of
Sc
ie
nc
e
(IOS
)
in
Univer
siti
T
ekn
ologi
MA
RA,
Mal
a
y
s
ia.
His
r
ese
arc
h
intere
st
s
are
Nano
-
Sc
i
enc
e
and
Nano
-
Te
chno
log
y
,
N
ano
-
Elec
tron
ic
Te
chno
log
y
Dev
ic
es
and
Ma
te
ri
a
ls.
Evaluation Warning : The document was created with Spire.PDF for Python.