The effect of annealing on structural, optical and photosensitive properties of electrodeposited cadmium selenide thin films

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Original Article

The effect of annealing on structural, optical and photosensitive

properties of electrodeposited cadmium selenide thin

ﬁlms

Somnath Mahato

a,b,*

, Asit Kumar Kar

aDepartment of Applied Physics, Indian Institute of Technology (Indian School of Mines) Dhanbad, 826004 Jharkhand, India
bSaha Institute of Nuclear Physics (Surface Physics and Material Science Division), 1/AF Bidhannagar, Kolkata 700064, India

a r t i c l e i n f o

Article history:

Received 2 December 2016
Received in revised form
7 April 2017

Accepted 9 April 2017
Available online 15 April 2017

Keywords:
CdSe
Thinﬁlm
Electrodeposition
XRD

Photosensitivity

a b s t r a c t

Cadmium selenide (CdSe) thinﬁlms have been deposited on indium tin oxide coated glass substrate by
simple electrodeposition method. X-ray Diffraction (XRD) studies identify that the as-deposited CdSe
ﬁlms are highly oriented to [002] direction and they belong to nanocrystalline hexagonal phase. The
ﬁlms are changed to polycrystalline structure after annealing in air for temperatures up to 450C and
begin to degrade afterwards with the occurrence of oxidation and porosity. CdSe completely ceases to
exist at higher annealing temperatures. CdSeﬁlms exhibit a maximum absorbance in the violet to
blue-green region of an optical spectrum. The absorbance increases while the band gap decreases with
increasing annealing temperature. Surface morphology also shows that the increase of the annealing
temperature caused the grain growth. In addition, a number of distinct crystals is formed on top of the
ﬁlm surface. Electrical characteristics show that the ﬁlms are photosensitive with a maximum sensitivity
at 350C.

© 2017 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi.
This is an open access article under the CC BY license ( />

1. Introduction

Semiconductors are very important and interesting because of
their technological applications in optoelectronics and
microelec-tronic devices like photodiodes[1], sensors[2], light emitting
di-odes[3], solar cells[4], photoelectrochemical cells[5], photovoltaic
cells[6]and photodetectors for optical communications etc. Among
them, Cadmium Selenide (CdSe) is a IIeVI group compound
semi-conducting material of the periodic table. This compound is a
highly photosensitive material in the visible region due to their
suitable band gap (1.74 eV).

Different processes such as chemical vapour deposition [7],
physical vapour deposition[8], thermal evaporation technique[9],
spray-pyrolysis[10], chemical bath deposition[11], dip coating[12]

and electrodeposition[13]have been used for depositing cadmium
selenide thinﬁlms. However, the electrodeposition process is one
of the simplest and low-cost techniques because it is easy to
manage and it requires very simple arrangement. Deposition rate is
easily controlled by changing deposition potential, concentration

and pH value of the electrolyte. Many groups are working on
cad-mium selenide using the process of electrodeposition[5,7,14e16].

The optoelectronic, microelectronic and other applications of
cadmium selenide thinﬁlms depend on their structural and
elec-tronic properties affecting device performance. These properties
are strongly inﬂuenced by the deposition parameters such as
deposition time, deposition potential, concentration of electrolytic
solution, pH of the electrolyte and thermal annealing. Thermal
treatment is one of the important factors to enhance the efﬁciency
and stability of photosensitive devices. Thus, studies of the effect of
annealing on structural, optical and electrical properties of thin
ﬁlms are very important in understanding and enhancing device
sensitivity[17e19].

The aim of this present work is to prepare cadmium selenide
thin ﬁlms by a simple electrodeposition process on indium tin
oxide (ITO) coated glass substrates and to study the effect of
annealing temperature (Ta) onﬁlms' photosensitivity. The effect of
annealing on crystallinity, morphology and optical absorbance of
theﬁlms are also presented and discussed.

* Corresponding author. Department of Applied Physics, Indian Institute of

Technology (Indian School of Mines) Dhanbad, 826004 Jharkhand, India.

E-mail address:(S. Mahato).

Peer review under responsibility of Vietnam National University, Hanoi.

Contents lists available atScienceDirect

Journal of Science: Advanced Materials and Devices

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / j s a m d

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2. Experimental
2.1. Film deposition

Cadmium selenide thinﬁlms have been deposited on indium tin
oxide coated glass substrates by using a simple two-electrode
electrodeposition process at room temperature (28 C). Sputter
coated ITO/glass was procured from Macwin India, Delhi. The
substrate, having sheet resistance 10

U

/sq, was used as a working
electrode or cathode, and aﬂat graphite rod was used as an anode.
The size of both the electrodes submersed in electrolyte was about
1 1 cm2and hence the area of deposition was about 1 cm2. The
electrodes were separated by a distance of about 1 cm. Substrates
were cleaned in acetone within an ultrasonic bath for 15 min and
then cleaned in running distilled water for 5 min and,ﬁnally, they
were dried in air for 15 min before deposition. For electrodeposition
of theﬁlms, cadmium chloride (CdCl2) and selenous acid (H2SeO3)
were used as the sources of cadmium and selenium, respectively in

the electrolyte; the molar concentrations of cadmium chloride and
selenous acid were 0.08 M and 0.005 M, respectively. The
electro-lyte was continuously stirred for 15 min in a beaker by using a
Teﬂon coated magnetic paddle attached to a stirrer, in order to
perfectly dissolve the ingredients in distilled water. All the
chem-icals were procured from Sigma Aldrich and had 99.99% purity. The
total volume of the prepared electrolyte was 100 ml pH. The value
of the electrolyte was kept at 1.9 by using HNO3 solution. The
deposition was conducted for 15 min with aﬁxed deposition 
po-tential of 1.80 V for all theﬁlms. After deposition, the thin ﬁlm
coated substrates were taken out from the electrolyte, then rinsed
in distilled water and dried in air. The as-deposited ﬁlms were
annealed at 250, 350, 450, 550 and 650C in the air for one hour in
a mufﬂe furnace with a ramp up rate of 2 C/min followed by
normal cooling to room temperature.

2.2. Reaction mechanism

The reaction mechanism of CdSe thinﬁlm is discussed as
fol-lows. The deposition process is based on the slow release of Cd2ỵ
ions and Se2ions in the solution ion-by-ion basis and settling on
the ITO coated glass substrates. The deposition takes place when
the ionic product of Cd2ỵand Se2is greater than the solubility
product. Cadmium selenide is deposited according to the following
over-all net reaction[20].

H2SeO3ỵ Cd2ỵỵ 6eỵ 4Hỵ#CdSe ỵ 3H2O

The rate of the formation of CdSe is determined by the bath
parameters such as pH, concentration and temperature of the

electrolyte[21].

2.3. Film properties

X-ray diffraction (XRD) patterns were recorded using XRD
(BRUKER D8 FOCUS) system with the Cu Karadiation (

l

¼ 1.5406 Å).

q

scan was taken for the range of 10e80with a speed of 0.20/
s and with a step size of 0.030. Optical absorption spectra were
obtained for the region 300 nme900 nm using UVeviseNIR
spectrophotometer. The microstructure and composition of the
CdSe thinﬁlms were studied using a scanning electron microscope
(FESEM, Model: JEOL JSM-5800 Scanning Microscope) and energy
dispersive analysis of X-ray (EDAX) module attached with the same
SEM system respectively. The electrical resistivity of the samples
was measured by the two-point probe technique. Currentevoltage
measurements in dark and illumination were accomplished using a
Keithley 2400 source metre. The light source was a 100 W (intensity

3.5 mW/cm2) tungsten bulb controlled by a dc power supply and it
was placed 20 cm away from the sample during experiment.
3. Results and discussion

3.1. Crystallinity

Cadmium selenide thinﬁlm grown on ITO coated glass substrate
is found to be polycrystalline with hexagonal (wurtzite) crystal
structure. Fig. 1(a) shows the XRD pattern of as-deposited or
unannealed CdSe thinﬁlm. The peak at 25.99corresponds to the
plane (002) which is much stronger than other peaks. The intense

peak at (002) suggests a dominant orientation of nanocrystalline
phase of CdSe thinﬁlm within an otherwise amorphous or nearly
amorphous matrix. The small hump in the background is due partly
to the amorphous nature of ITO coated glass substrate and also may
be due to some amorphous phase presented in the CdSe thinﬁlm
itself[22].Fig. 1(b)e(f) shows the XRD patterns of annealed ﬁlms.
Annealing at 250C [Fig. 1(b)] makes theﬁlm more oriented
to-wards (002) plane. The polycrystalline hexagonal CdSe phase is
found after annealing at 350C [Fig. 1(c)]. Intensity of the most
intense peak is continuously found to decrease with the increase of
annealing temperature. It signiﬁes a gradual change of a highly
oriented nanocrystalline phase to a polycrystalline phase. Further
heat treatment from 450C to 650C shows that the CdSe phase
gradually changes to CdO phase [Fig. 1(d)e(f)]. At the annealing
temperature 550C and above, CdSe completely disappears. All the
XRD patterns from Figs. (d)e(f) show the characteristic diffraction
peaks of (111) and (200) planes of polycrystalline hexagonal CdO
phase. Other peaks (211) at 21.88, (222) at 30.91, (400) at 35.68
and (622) at 61.18correspond to ITO. This suggests that the after
annealing of CdSe thin ﬁlms in air at a higher temperature
[Ta 450C], reaction occurs and chemically a new phase
forma-tion takes place; the polycrystalline phase of CdO gradually prevails
over the polycrystalline phase of CdSe with increase in
tempera-ture. XRD plots from (a) to (f) also exhibit gradual reduction in
overall peak intensity and hence a rise in background intensity.
They also demonstrate the appearance of more ITO peaks with
enhanced intensity at higher annealing temperature. These facts
might be related to the gradual loss of CdSe and later CdO [Figs. (e)
and (f)] from the surface of the thinﬁlms due to sublimation during
annealing and the possibility of diffusion into the substrate may be

ruled out.

Average crystallite size of CdSe ﬁlms is found to vary from
16.8 nm to 21.9 nm. This was calculated from Scherrer's formula
using full width at half maximum (FWHM)

b

of the peaks of XRD
proﬁles[23e25].

D¼ K

l

b

hklcos

q

(1)

where D ¼ crystallite size, K ¼ shape factor (0.9), and

l

¼ wavelength of Cu Karadiation.

The microstrain (ε) values have been calculated by using the
following formula:

ε ¼

b

hkl

4 tan

q

(2)

Assuming that, the particle size and strain are independent of
each other, equations(1) and (2)may be combined to the following
form:

b

hklcos

q

l

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This is known as WilliamsoneHall formula[26]. The graph was
plotted between

b

hklcos

q

versus 4 sin

q

as shown inFig. 2. From
the linearﬁt to the data, the crystallite size was estimated from the
intercept along ordinate, and strain (ε) was found from the slope of
theﬁt. From WilliamsoneHall (WeH) method the average
crys-tallite size is determined to be 31.5 nm for CdSe thinﬁlm annealed
at 450C.

The dislocation density

d

has been calculated by using the
for-mula for the highly intense X-ray diffraction peaks.

d

¼15ε

aD: (4)

All the calculated values are shown inTable 1. As expected,

increase in annealing temperature leads to increase in crystallite
size, and decrease in strain and dislocation density of theﬁlms.
3.2. UVeviseNIR spectroscopy

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increases and the broad peak shifts from violet to blue-green region
with increasing annealing temperature. It may be due to increased
crystallite size in the thinﬁlms. The colour of the ﬁlm is found to
change from red-orange to dark black after annealing. The values of
the band gap of theﬁlms have been determined from transmission
spectra by using the following relation applicable to near edge
optical absorption of semiconductors:

a

K
h

n

n (5)

where

a

is absorption co-efﬁcient, h

n

is the photon energy, K is a
constant, Egis the band gap and n is a constant which equals to½
for allowed direct band-gap semiconductor in the present case

[27,28]. The band gap energy of CdSe/ITO thin ﬁlm has been
determined by Tauc plot based on the above formula as shown in

Fig. 4. The optical band gaps are found to be 2.13 eV, 1.95 eV, 1.91 eV
and 1.88 eV for thinﬁlms of as-deposited and annealed at 250, 350
and 450C temperature respectively. The band gap of as-deposited
or unannealedﬁlm is higher compared to the annealed CdSe thin
ﬁlms because the deposition at room temperature gives rise to
ﬁlms with smaller crystallite size. So the energy band gap of CdSe
thin ﬁlms tend to decrease as the annealing temperature is
increased due to increased crystallite size of theﬁlms.

The value of the extinction coefﬁcient (k) is calculated from the
following relation[29]:

k¼4

al

p

(6)

The graphical representation of the variation of extinction
co-efﬁcient with wavelength is shown inFig. 5. The graph shows that
even for the photons having energy above band gap, the absorption
coefﬁcient is not constant and strongly depends on wavelength. For
photons which have energy very close to that of the band gap, the
absorption is relatively low since only the electrons at the valence

band edge can interact with the photon to cause absorption. As the
photon energy increases, not just the electrons already having
energy close to that of the band gap can interact with the photons, a
larger number of other electrons below band edge can also interact
with the photons resulting in absorption. Thus extinction coef
ﬁ-cient has high values near the absorption edge and it has very small
values at higher wavelengths.

3.3. Surface morphology

The surface morphology of as-depositedﬁlm and annealed ﬁlms
has been studied using FESEM as shown inFig. 6(a)e(f). Surface
Fig. 2. WeH plot for a ﬁlm annealed at 450C.

Table 1

Structural parameters for as-deposited and annealed CdSe thinﬁlms calculated from their corresponding XRD proﬁles.

Ta(C) Crystallite size (nm) Lattice parameters (Å) Strain (ε) Dislocation densityd(1017/m2)

a c

Unannealed 16.8 4.24 6.93 0.526 11.09

250 18.1 4.24 6.93 0.492 9.62

350 18.2 4.24 6.93 0.485 9.43

450 31.5a 4.24 6.93 0.413a 6.68

aCalculated from WeH plot.

Fig. 3. UVeviseNIR absorbance and transmittance (inset) spectra of CdSe/ITO thin
ﬁlms annealed at different temperatures.

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topography of as-deposited ﬁlm is shown inFig. 6(a). From the
topograph, it is observed that the as-depositedﬁlms are continuous
with homogeneous distribution of densely packed blister-like
particles of nonuniform size varying from several tens of
nano-metre to about 250 nm.Fig. 6(b) shows a cross-sectional tilted view
of the ﬁlm annealed at 250 C; spherical nanosized grains of
globule-like structure are observed with several 100 nm in size and
the grains are closely packed with each other to form a crystalline
matrix. A wide view of the corresponding area has been presented
inFig. 6(e), which covers parts of both cross-sectional and surface
features. It appears that after annealing, the particulate features

were more uniform in size, reducing the range of variation

observed in as-deposited ﬁlms. At the annealing temperature
350C [Fig. 6(c)], it is found that theﬁlms become rougher with the
development of some pebble-like crystalline surface features of
size varying from about 50 nm to 300 nm. Apparently the
blister-like features inﬁgure (a) have played the role of growth centres
and crystalline features are developed through the process of
sur-face and volume diffusion with increase in temperature. The SEM
micrographs of theﬁlm annealed at 450C are shown inFigs. 6(d)
and (f) where the latter represents a wide area view. A drastic
change in crystalline structural features is observed for 100C
in-crease in annealing temperature with respect toFig. 6(c). Excellent
single crystalline structures of width as big as 1.5

m

m with various
polygon like[30]facets are noticed to evolve on theﬁlm surface but
with very less in number compared to theﬁlm annealed at 350C.
Some pores are also found to develop on the surface of theﬁlm of
irregular shape appearing like crystalline voids. Other than the
crystals on the surface and the pores, the surface of theﬁlm appears
to be smooth with clear demarcation of crystalline grains i.e. grain
boundaries. Grain size varies from about 100 nm to 500 nm. Top
surfaces of the embedded crystalline grains are found to form a nice
mosaic pattern.

Due to annealing, a number of smaller grains or crystals diffuse
and coalesce together to effectively form larger crystalline grains
with clear crystallographic faces. Above mentioned results
demonstrate that the process of annealing induces two parallel
grain growth processese one within the volume of the thin ﬁlm
matrixe a primary growth process, and the other over the thin ﬁlm
surfacee a secondary growth process. Crystalline nature of CdSe
thinﬁlms is also indicated by XRD measurement.

Thickness of theﬁlms was found to be about 6

m

m by
cross-sectional imaging in SEM. Energy dispersive analysis of X-rays
(EDAX) conﬁrms the presence of both Cd and Se in the ﬁlms. It also
reveals that the thinﬁlms annealed at different temperatures are
nonstoichiometric in nature.

Fig. 5. Dispersion curves of extinction coefﬁcient (k) for as-deposited and annealed
CdSe/ITO thinﬁlms.

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3.4. Electrical property

The electrical resistivity of CdSe/ITO thin ﬁlm has been
measured by using dc two probe methods. It is determined by
loading a direct current I and measuring a voltage drop V between
two probes which are placed at a distance (s) of 1 mm, using the
following equation[31,32]:

r

¼ 2

p

I (7)

At room temperature the speciﬁc conductance was found to be
of the order of 104(

U

1cm1).

For photoconductivity measurement of CdSe thinﬁlms, area of
theﬁlm exposed to light was 1 1 cm2. The dark and illumination
IeV characteristics of CdSe thin ﬁlms were recorded as shown in

Fig. 7(a) as an example. All theﬁlms under dark conditions showed

good rectifying nature. They also responded to illumination giving
rise to photocurrent with again rectifying nature or asymmetric
semiconducting nature. The characteristic curves demonstrated
that the photo response was sensitive to annealing temperature.

The photosensitivity S of the ﬁlms was calculated using the
following formula:

s¼

s

light

s

s

dark

(8)

where

s

photo is the photoconductivity and

s

dark is the dark
con-ductivity[9]. The as-deposited CdSe thinﬁlms show weak
photo-conductivity and its sensitivity is less (S ~ 3). Annealing at 250C
reveals increased photoconductivity and its sensitivity increases to
~12. The photoconductivity is found to dramatically improve
(S ~ 64) at 350C annealing temperature. So it is observed that the
photosensitivity is increased with the increase of annealing
tem-perature as shown inFig. 7(b). The reason is associated with the
increased absorbance of the incident light in visible region with
increase in annealing temperature. Enhancement in the
photo-conductivity is due to the generation of more electron-hole pairs
excited by the incident light. Annealing at 450 C leads the
photoconductivity to fall to zero because of the phase change and
accompanying degradation of CdSe thinﬁlm. At this temperature,
microstructural defects like pores and formation of secondary
phase like CdO impair and saturate the conduction of charge

car-riers even after their enhanced generation due to higher
absor-bance. The result may be beneﬁcial to the development of large

area, low cost, and good quality CdSe thinﬁlms for photodiode and
photovoltaic applications.

4. Conclusion

The CdSe thin ﬁlms have been successfully deposited by a
simple two electrode electrodeposition method on ITO coated glass
substrates. The process of annealing in air has been found to change
the crystallinity of ﬁlms from highly oriented nanocrystalline
(hexagonal wurtzite) structure to polycrystalline form. With
annealing globular nanocrystalline grains become bigger and a
number of distinct micro-crystals are developed on top of theﬁlm
surface; the crystals grow to a maximum in size at 450C having
clear crystallographic faces on their surface. For annealing
tem-peratures higher than 450C, CdSe is chemically degraded and is
converted to CdO. The CdSeﬁlms exhibit strong absorbance in the
violet to blue-green region. With increase in the annealing
tem-perature, the band gap decreases from 2.13 eV to 1.88 eV for the
as-deposited and 450Cﬁlms. The CdSe ﬁlms are photosensitive; the
sensitivity increases with annealing temperature up to 350C and
then decreases.

Acknowledgements

Authors are grateful to Dr. B. Pandey, Dr. N. Das, Dr. D. Roy and
Mr. A. Jana of the Department of Applied Physics, IIT (ISM)
Dhan-bad, for their assistance in optical and electrical measurements.

References

[1] S. Dayal, N. Kopidakis, D.C. Olson, D.S. Ginley, G. Rumbles, Photovoltaic devices
with a low band gap polymer and CdSe nanostructures exceeding 3%
efﬁ-ciency, Nano Lett. 10 (2010) 239e242.

[2] G. Zou, H. Ju, Electrogenerated chemiluminescence from a CdSe nanocrystal
ﬁlm and its sensing application in aqueous solution, Anal. Chem. 76 (2004)
6871e6876.

[3] S. Bera, S.B. Singh, S.K. Ray, Green route synthesis of high quality CdSe
quantum dots for applications in light emitting devices, J. Solid State Chem.
189 (2012) 75e79.

[4] S.K. Saha, A. Guchhait, A.J. Pal, Organic/inorganic hybrid pn-junction between
copper phthalocyanine and CdSe quantum dot layers as solar cells, J. Appl.
Phys. 112 (2012) 044e507.

[5] S.K. Shinde, G.S. Ghodake, D.P. Dubal, G.M. Lohar, D.S. Lee, V.J. Fulari,
Struc-tural, optical, and photo-electrochemical properties of marygold-like
CdSe0.6Te0.4 synthesized by electrochemical route, Ceram. Int. 40 (2014)
11519e11524.

</div>
(7)<div class='page_container' data-page=7>

[7] L.K. Teh, V. Furin, A. Martucci, M. Guglielmi, C.C. Wong, F. Romanato,
Elec-trodeposition of CdSe on nanopatterned pillar arrays for photonic and
photovoltaic applications, Thin Solid Films 515 (2007) 5787e5791.
[8] Y.G. Gudage, R. Sharma, Growth kinetics and photoelectrochemical (PEC)

performance of cadmium selenide thinﬁlms: pH and substrate effect, Curr.
Appl. Phys. 10 (2010) 1062e1070.

[9] A. Purohit, S. Chander, S.P. Nehra, C. Lal, M.S. Dhaka, Effect of thickness on
structural, optical, electrical and morphological properties of nanocrystalline
CdSe thin ﬁlms for optoelectronic applications, Opt. Mater. 47 (2015)
345e353.

[10] A.A. Yadav, M.A. Barote, E.U. Masumdar, Studies on cadmium selenide (CdSe)
thinﬁlms deposited by spray pyrolysis, Mater. Chem. Phys. 121 (2010) 53e57.
[11] S. Devadason, M.R. Muhamad, Structural and optical properties of vapour

deposited multi-layer CdSe thinﬁlms, Phys. B 393 (2007) 125e132.
[12] P.P. Hankare, P.A. Chate, D.J. Sathe, M.R. Asabe, B.V. Jadha,

Photo-electrochemical studies of CdSe thinﬁlms deposited by dip method, J. Alloys
Compd. 474 (2009) 347e350.

[13] S. Mahato, N. Shakti, A.K. Kar, Annealing temperature dependent structural
and optical properties of electrodeposited CdSe thinﬁlms, Mater. Sci.
Semi-cond. Process. 39 (2015) 742e747.

[14] Z. Gao, W. Jin, Y. Li, Q. Song, Y. Wang, K. Zhang, S. Wang, L. Dai, Flexible solar
cells based on CdSe nanobelt/graphene Schottky junctions, J. Mater. Chem. C
(2015).

[15] S.K. Shinde, D.P. Dubal, G.S. Ghodake, D.S. Lee, G.M. Lohar, M.C. Rath,
V.J. Fulari, Baking impact of Fe composition on CdSe ﬁlms for solar cell
application, Mater. Lett. 132 (2014) 243e246.

[16] R. Henriquez, A. Badan, P. Grez, E. Munoz, J. Vera, E.A. Dalchiele, R.E. Marotti,
H. Gomeza, Electrodeposition of nanocrystalline CdSe thin ﬁlms from

dimethyl sulfoxide solution: nucleation and growth mechanism, structural
and optical studies, Electrochim. Acta 56 (2011) 4895e4901.

[17] X. Wang, W. Tian, M. Liao, Y. Bando, D. Golberg, Recent advances in
solution-processed inorganic nanoﬁlm photodetectors, Chem. Soc. Rev. 43 (2014)
1400e1422.

[18] S.N. Sarangi, S.N. Sahu, CdSe nanocrystalline thinﬁlms: composition, structure
and optical properties, Phys. E 23 (2004) 159e167.

[19] S. Chaure, N.B. Chaure, R.K. Pandey, Self-assembled nanocrystalline CdSe thin
ﬁlms, Phys. E 28 (2005) 439e446.

[20] S. Mahato, A.K. Kar, Structural, optical and electrical properties of
electro-deposited cadmium selenide thinﬁlms for applications in photodetector and
photoelectrochemical cell, J. Electroanal. Chem. 742 (2015) 23e29.

[21] S.M. Pawar, A.V. Moholkar, K.Y. Rajpure, C.H. Bhosale, Electrosynthesis and
characterization of CdSe thinﬁlms: optimization of preparative parameters by
photoelectrochemical technique, J. Phys. Chem. Solids 67 (2006) 2386e2391.
[22] R.B. Kale, C.D. Lokhande, Band gap shift, structural characterization and phase
transformation of CdSe thinﬁlms from nanocrystalline cubic to nanorod
hexagonal on air annealing, Semicond. Sci. Technol. 20 (2005) 1e9.
[23] S.B. Jambure, C.D. Lokhande, Photoelectrochemical solar cells with chemically

grown CdO rice grains onﬂexible stainless steel substrates, Mater. Lett. 106
(2013) 133e136.

[24] U. Cevik, E. Bacaksiz, N. Damla, A. Çelik, Effective atomic numbers and electron
densities for CdSe and CdTe semiconductors, Radiat. Meas. 43 (2008)

1437e1442.

[25] C.H. Han, S.D. Han, J. Gwak, S.P. Khatkar, Synthesis of indium tin oxide (ITO)
andﬂuorine-doped tin oxide (FTO) nano-powder by solegel combustion
hybrid method, Mater. Lett. 61 (2007) 1701e1703.

[26] A.K. Zak, W.H.A. Majid, M.E. Abrishami, R. Youseﬁ, X-ray analysis of ZnO
nanoparticles by WilliamsoneHall and sizeestrain plot methods, Solid State
Sci. 13 (2011) 251e256.

[27] S.K. Shinde, D.P. Dubal, G.S. Ghodake, V.J. Fulari, Morphological modulation of
Mn:CdSe thinﬁlm and its enhanced electrochemical properties, J. Electroanal.
Chem. 727 (2014) 179e183.

[28] S. Mahato, Nanda Shakti, A.K. Kar, Annealing temperature dependent
struc-tural and optical properties of electrodeposited CdSe thinﬁlms, Mater. Sci.
Semicond. Process. 39 (2015) 742e747.

[29] T.S. Shyju, S. Anandhi, R. Indirajith, R. Gopalakrishnan, Solvothermal synthesis,
deposition and characterization of cadmium selenide (CdSe) thinﬁlms by
thermal evaporation technique, J. Cryst. Growth 337 (2011) 38e45.
[30] T.S. Shyju, S. Anandhi, R. Indirajith, R. Gopalakrishnan, Effects of annealing on

cadmium selenide nanocrystalline thin ﬁlms prepared by chemical bath
deposition, J. Alloys Compd. 506 (2010) 892e897.

[31] S. Erat, H. Metina, M. Ar, Inﬂuence of the annealing in nitrogen atmosphere on
the XRD, EDX, SEM and electrical properties of chemical bath deposited CdSe
thinﬁlms, Mater. Chem. Phys. 111 (2008) 114e120.

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The effect of annealing on structural, optical and photosensitive properties of electrodeposited cadmium selenide thin films

Original Article