Tin Sulfide Thin Films Research Articles

Evaluation of semiconducting p-type tin sulfide thin films for photodetector applications

Abstract Tin sulfide (SnS) is an important semiconductor as it is one of the less common p-type materials with a bandgap of 1.53 eV which makes it an attractive material for photo detector application. In the thin film form, it is a sensitive photo conductor with attractive opto-electronic characteristics. In the current report, tin sulfide thin films have been deposited by thermal evaporation in vacuum and the influence of substrate temperature on its compositional, morphological, structural, and opto-electrical properties was studied. X-ray diffraction (XRD) study shows that all the thermally deposited films are having an orthorhombic crystal structure along (111) plane as pre-dominant orientation and are polycrystalline in nature. Raman analysis verify the occurrence of SnS and Sn2S3 phases in the films. Surface morphology along with the elemental composition of the films was determined by scanning electron microscopy (SEM) in combination with energy dispersive spectroscopy (EDS). All the films were found to be homogeneous, uniform, pin-hole free and have high optical transmittance in the UV–Vis wavelength region. The optical bandgap energy of the films was calculated using Tauc's relation and it was found to be decreasing (1.576 eV–1.429 eV) with increasing substrate temperature. The activation energy of the SnS thin films was calculated from Arrhenius plot and it was also found to be decreasing with increasing substrate temperature. The opto-electrical parameters such as photo conductivity (σL), dark conductivity (σD), response time (τr), recovery time (τd), photoresponsivity (R), and photosensitivity (S) were calculated and was found best for the films grown at 323 K.

Enhancement in photovoltaic properties of Nd:SnS films prepared by low-cost NSP method

The inner transition metal (ITM) neodymium (Nd)-doped tin sulfide (Nd:SnS) thin films with various Nd concentrations were coated by nebulizer spray pyrolysis (NSP) technique at 350 °C. All the coated films were analyzed for their structural, optical and photoelectrical properties. X-ray diffractometer (XRD) study showed (111) direction as the highly preferred orientation with orthorhombic crystal structure for all the films. The intensity of the peaks was found to increase until 5 at% Nd doping and then reduced for higher (7 at% Nd) doping concentration. Atomic force microscopic (AFM) images of the films proclaimed an increase in the surface and line roughness of the films by increasing Nd concentrations. Optical analysis on the films showed a variation in energy gap from 2.05 to 1.69 eV when the doping concentration increased from 0 at% to 7 at%. At 5 at% Nd doping, the photoluminescence (PL) spectra displayed a single strong emission peak at 723.1 nm with enhanced intensity corresponding to near-band-edge emission. All the SnS thin films exhibited p-type behavior with the lowest resistivity of ~ 4.311 Ω·cm and high carrier concentrations of ~ 1.441 × 1017 cm−3 for 5 at% Nd doping level as observed from Hall effect studies. Furthermore, fluorine-doped tin oxide (FTO)/n-CdS/p-Nd:SnS hetero-junction solar cells were prepared and the current–voltage curve in dark and light condition was obtained for the device. An efficiency of 0.135% was observed for the solar cell fabricated with 5 at% Nd-doped SnS thin film.

Modelling of novel-structured copper barium tin sulphide thin film solar cells

In this work, a novel structured Cu\(_{2}\)BaSnS\(_{4}\) (\(\hbox {CBTS})/\hbox {ZnS}/\hbox {Zn}({\hbox {O},\hbox {S}})\) photovoltaic device is proposed. A nontoxic, earth-abundant and auspicious quaternary semiconductor compound copper barium tin sulphide \(\left( {\hbox {Cu}_2 \hbox {BaSnS}_4 } \right) \) is used as an absorber layer. We propose a novel \(\hbox {Zn}({\hbox {O},\hbox {S}})\) buffer layer for a high-power conversion efficiency (PCE) of \(\hbox {CBTS}\)-based thin film photovoltaic cells. Solar cell capacitance simulator software is used for device modelling and simulations are performed under a 1.5 AM illumination spectrum. The proposed device is investigated by means of numerical modelling and optimized the parameters to maximize its efficiency. Promising optimized functional parameters had been achieved from the proposed structure with back surface field layer with a PCE of 18.18%, a fill factor of 83.45%, a short-circuit current of 16.13 \(\hbox {mA}\,\hbox {cm}^{-2}\) and an open-circuit voltage of 1.3 V. The promising results give an imperative standard for possible manufacturing of high efficiency, eco-friendly inorganic \(\hbox {CBTS}\)-based photovoltaic cells.

Growth and Characterization of Tin Sulphide Nanostructured Thin Film by Chemical Bath Deposition for Near-Infrared Photodetector Application

This study involves synthesizing of nanostructured tin sulphide (SnS) thin film on a glass substrate by chemical bath deposition technique. SnS film was prepared using non-toxic trisodium citrate (TSC) as a complex agent. The structural and morphological characteristics of the film were characterized by using X-ray diffraction (XRD), optical field emission scanning electron microscopy (FESEM). The XRD pattern confirmed an orthorhombic structure. The FESEM image revealed nanoflakes of the as-prepared SnS thin film. Moreover, near-infrared (NIR) metal semiconductor metal photodetector, which exhibited good photoresponse characteristics under (750 nm) light illumination was fabricated. The photoresponse characteristics also were investigated at different illumination power densities. The photodetector revealed excellent reproducibility and stability characteristics.

Effect of carrier gas pressure on structural, optical and photovoltaic properties of tin sulphide thin films prepared by nebulizer spray pyrolysis method

Tin sulphide (SnS) thin films deposited using nebulizer spray pyrolysis technique by changing pressure (0.1, 0.15, 0.2 and 0.25 Pascal) at $$350^{\circ }\hbox {C}$$ and their characterization are reported. The influence of carrier gas pressure on structural, morphological, optical and electrical properties of the film are determined using X-ray diffraction (XRD), energy-dispersive X-ray, atomic force microscopy, UV–Vis spectrophotometry and Hall effect measurement. Structural parameters such as pole density, orientation factor, crystallite size, micro strain and dislocation density were analysed using XRD data. The scanning electron microscopy studies display superior morphology and surface roughness of the films which were found to increase with pressure. Optical studies on the films revealed a variation in band gap from 1.78 to 1.66 eV for were the raise of pressure from 0.1 to 0.2 Pa. A single strong emission peak at about 825 nm is observed in photoluminescence spectra with enhanced intensity which may be attributed to near band edge emission. Grown SnS thin film exhibits p-type conductivity, which was confirmed from the Hall effect measurement. The low resistivity and higher carrier concentration are found to be $$0.235\,\Omega \,\hbox {cm}$$ and $$5.04\times 10^{18}\,\hbox {cm}^{-3}$$ , respectively. These properties were then correlated with the deposition parameters. Furthermore, to study the photovoltaic properties of SnS thin films, a heterojunction solar cell FTO/n-CdS/p-SnS/Al was fabricated showing conversion efficiency of 0.16%.

Investigations on Fe doped SnS thin films by nebulizer spray pyrolysis technique for solar cell applications

Undoped and different concentrations of iron (Fe) doped tin sulphide (SnS) thin films were coated by nebulizer spray pyrolysis method with the substrate temperature of 350 °C. Polycrystalline nature of orthorhombic crystal structured pure and Fe doped SnS (Fe:SnS) thin films confirmed by X-ray diffraction (XRD) patterns. Structural studies further explored the preferential orientation of (201) plane for undoped SnS and their shifts to (400) and (111) directions for Fe:SnS at 6 and 10 wt.% of Fe concentration, respectively. The versatile route of structural modification has obviously demonstrated due to inclusion of Fe doping in SnS. Raman spectra further confirmed the structural variation of Fe:SnS. Topological variations obviously explained by atomic force microscopy images for pure and Fe:SnS. Optical results evidently claimed the deterioration of band gap values from 1.96 to 1.58 eV due to increase of Fe doping concentrations from 0 to 10 wt.%, respectively. Luminescence spectra showed a strong emission peak centered at 772 nm and low resistivity 3.32 × 10−2 Ω cm with the high carrier concentration for 8 wt.% of Fe concentration using prepared Fe:SnS film. The fabricated solar cell device with n-CdS exposed the 0.18% of efficiency for p-Fe:SnS prepared using 8 wt.% Fe concentration.

Shape- and size-tunable synthesis of tin sulfide thin films for energy applications by electrodeposition

Size and shape tunable tin sulfide (SnS) thin film structures are successfully prepared by a simple cost-effective electrodeposition route. Scanning electron micrographs (SEM) effectively demonstrated the SnS shape modification. An ethylenediaminetetraacetic acid (EDTA) electrolyte was successfully used to alter the size of SnS. The SEM results also give evidence of the surface modification of SnS which was prepared with EDTA. Atomic force micrographs established the topological variations of SnS. Energy dispersive X-ray results confirmed the stoichiometric composition SnS prepared with and without EDTA. X-ray diffraction results revealed the polycrystalline orthorhombic structure of the SnS thin film. The optical band gap derived from the Tauc's plot was found to be in the 1.23–1.26 eV range. The near band edge emission peak for SnS was observed using photoluminescence properties. This simple strategy to synthesize a smooth, dense-packed and crack-free morphology could be an attractive way to produce SnS as a capable material for energy harvesting and optoelectronic devices.

Impact of thickness and heat treatment on some physical properties of thin Cu2SnS3 films

Copper tin sulfide (Cu2SnS3) thin films have been grown on glasssubstrate with different thicknesses (500, 750 and 1000) nm by flashthermal evaporation method after prepare its alloy from theirelements with high purity. The as-deposited films were annealed at473 K for 1h. Compositional analysis was done using Energydispersive spectroscopy (EDS). The microstructure of CTS powderexamined by SEM and found that the large crystal grains are shownclearly in images. XRD investigation revealed that the alloy waspolycrystalline nature and has cubic structure with preferredorientation along (111) plane, while as deposited films of differentthickness have amorphous structure and converted to polycrystallinewith annealing temperature for high thickness. AFM measurementsshowed that the grain size of the films was increasing by annealing.The ultraviolet- visible absorption spectrum measurement indicatedthat the films have a direct energy band gap. Eg decrease withthickness and increase with annealing.

The Morphological Changes of SnS Thin Films Deposited on Stainless-Steel Substrates at Low Temperatures

Orthorhombic tin sulfide (SnS) thin films have been deposited on stainless steel (SS) substrates by Chemical Bath Deposition (CBD) at 25, 35 and 70 °C with a deposit time of 8 hours each one. XRD analysis showed that samples obtained at 25 °C and 70 °C present very small diffraction peaks. This can be attributed in the case of the sample obtained at 25 degrees, that the crystallization process is not completed because the temperature is so low and in case of the sample deposited at 75 degrees, a redissolution of the material is carried out. However, sample obtained at 35 °C was polycrystalline with orthorhombic structure and preference plane (111). All samples showed the Raman vibrational modes TO and LO of the SnS and confirms that the samples do not have by-products. It was observed from SEM micrographs that the films consisted of spheres for the sample deposited at 25 °Candsmall flakes for the other samples. From diffuse reflectance measurements the optical band gap calculated was between 1.45 eV to 1.59 eV.

Morphological Changes of SnS Thin Films Deposited on Stainless-Steel Substrates at Low Temperatures

Orthorhombic tin sulfide (SnS) thin films have been deposited on stainless steel (SS) substrates by Chemical Bath Deposition (CBD) at 25, 35 and 70 °C with a deposit time of 8 hours each one. XRD analysis showed that samples obtained at 25 °C and 70 °C present very small diffraction peaks. This can be attributed in the case of the sample obtained at 25 degrees, that the crystallization process is not completed because the temperature is so low and in case of the sample deposited at 75 degrees, a redissolution of the material is carried out. However, sample obtained at 35 °C was polycrystalline with orthorhombic structure and preference plane (111). All samples showed the Raman vibrational modes TO and LO of the SnS and confirms that the samples do not have by-products. It was observed from SEM micrographs that the films consisted of spheres for the sample deposited at 25 °Candsmall flakes for the other samples. From diffuse reflectance measurements the optical band gap calculated was between 1.45 eV to 1.59 eV.

Synthesis Of Spray Pyrolysed Copper Doped Tin Sulfide (SnS:Cu) Thin Films By Optimizing The Anionic Precursor Molarity

Recent research in the field of photovoltaic, givesemphasis on materials which are earth abundant and non toxic in nature; along with that it should be possible to synthesize using an easy deposition technique. In this regard SnSattain a great attentionrecently. But naturally it exists as p-type material and can be converted into n-type. The n-type polarity conversion is now a growing research field and so far very few works havebeen reported.Thus it is vital to understand its potential by optimizing various parameters, so as to use in photovoltaics. In the present work, we have optimized the required anionic molarity to fabricate good opto-electronic n-type copper doped tin sulfide (SnS:Cu) thin films using chemical spray pyrolysis method (CSP). Here we prepared and characterized theSulfur molarity varied thin films. The doping percentage ofCu and Tin molarity is kept constant.Molarity of Sulfur is varied as (Sn:S) 0.1:0.1,0.1:0.2,0.1:0.3 and 0.1:0.4.The corresponding changes in structural, electrical and optical properties of these films are studied.

Electric Double Layer Field Effect Transistor Using SnS Thin Film as Semiconductor Channel Layer and Honey Gate Dieletric

The study aimed at the investigation and application of SnS thin film semiconductor as a channel layer semiconductor in the assembly of an electric double layer field effect transistor which is important for the achievement and development of novel device concepts, applications and tuning of physical properties of materials since the reported EDLFET and the modulation of electronic states have so far been realised on oxides, nitrides, carbon nanotubes and organic semiconductor but has been rarely reported for the chalcogenides. Honey was used as a gel like electrolytic gate dielectric to generate an enhanced electric field response over SnS semiconductor channel layer and due to its ability to produces high on-current and low voltage operation while forming an ionic gel-like solution similar to ionic gels which consist of ionic liguids. SnS gated honey Electric double layer field effect transistor was assembled using tin sulphide (SnS) thin film as semiconductor channel layer and honey as gate dielectric. The measured gate capacitance of honey using LCR meter was measured as 2.15 μF/ cm2 while the dielectric constant is 20.50. The semiconductor layer was deposited using Aerosol assisted chemical vapour deposition and annealed in open air at 250 on an etched region about the middle of a 4×4 mm FTO glass substrate with the source and drain electrode region defined by the etching and masking at the two ends of the substrate. Iridium was used as the gate electrode while a copper wire was masked to the source and drain region to create electrode contact. The Profilometry, X-ray diffraction, Scanning electron microscope, Energy dispersive X-ray spectroscopy, Hall Effect measurement and digital multimeters were used to characterise the device. The SnS thin film was found to be polycrystalline consisting of Sn and S elements with define grains, an optical band of 1.42 eV and of 0.4 μm thickness. The transistor operated with a p type channel conductivity in a depletion mode with a field effect mobility of 16.67 cm2/Vs, cut-off voltage of 1.6 V, Drain saturation current of1.35μA, a transconductance of -809.61 nA/V and a sub threshold slope of -1.6 Vdec-1 which is comparable to standard specifications in Electronics Data sheets. Positive gate bias results in a shift in the cut off voltage due to charge trapping in the channel/dielectric interface.

Photovoltaic behavior of the room temperature grown RF-Sputtered SnS thin films

Tin sulfide (SnS) thin films were deposited on the soda lime glass (SLG) and Mo-coated SLG by radio frequency sputtering method at room temperature (RT). The structural, optical, and the photovoltaic properties were investigated by varying the argon pressure (PAr) from 6 to 50 mTorr. The scanning electron microscopy (SEM), electron dispersive spectroscopy (EDX), X-ray diffraction (XRD), micro-Raman spectroscopy, and photoluminescence spectroscopy (PL) confirmed that the as-grown samples at 30 mTorr pressure showed the single phase of orthorhombic SnS with the stoichiometric ratio. The variation in the grain size, shape, and a shift in the crystal plane from (111) to (101) were ascertained with an increase of PAr. The ultraviolet–visible spectroscopy revealed that all the SnS films exhibited a constant high optical absorption coefficient of 5.8 × 104 cm−1, whereas, the energy band gap reduced from 1.50 to 1.35 eV with the increase of PAr. The solar cell of RT-SnS at 30 mTorr showed the best power conversion efficiency of 0.38%.

Optical and morphological properties of environmentally benign Cu-Tin sulphide thin films grown by physical vapor deposition technique

Present work has set about the synthesis of Tin-Diethyl dithiocarbamate Sn (S2CN (Et) 2) n]) and Copper diethyldithiocarbamate Cu (S2CN(Et)2) complex by utilizing single source method. Sn (S2CN (Et) 2) n]) complex are further used for deposition of Tin Sulphide thin films via Physical Vapor deposition with varying concentration of copper acting as dopant specie. The fabricated doped and un-doped films were confronted to functional group detection (FTIR), optical (UV–vis), structural (XRD) and morphological (SEM, EDX) analysis to retrieve the hidden information. FTIR peaks of Copper and Tin complex confirmed the formation of dithiocarbamate complexes by enumerating the stretching and bending vibrational modes of bonding and metal Sulphur linkage. X-ray diffraction elucidate the predominant phase of SnS with 1:1 ratio which depicted the fabrication at high temperature. Optical investigation represented the decrease in band gap by 6% extrinsic addition while increase at 10% doping. The enhancement in band gap is also clear from the increased absorption edge upon 10% addition. Surface morphology of films was heterogeneous along flakes with compaction of spherical particles as demonstrated by SEM. The obtained results of material (SnS) being environmentally benign were therefore discussed to assess its aptness in optoelectronic devices.

Tin sulfide: Reduced graphene oxide nanocomposites for photovoltaic and electrochemical applications

Nanocomposite thin films of tin sulfide (SnS) with graphene oxide (GO) and reduced graphene oxide (rGO) were prepared by spray deposition of tin sulfide nanocolloids mixed with graphene oxide. SnS nanocolloidal suspensions were synthesized by liquid phase pulsed laser ablation of a SnS target in isopropyl alcohol and dimethyl formamide. Spherical morphology and orthorhombic crystalline structure of the nanoparticles were determined by transmission electron microscopy. Graphene oxide was synthesized through a chemical pathway (Marcano's method) and was mixed with SnS nanocolloid. Thin films were deposited by spraying SnS nanocolloid as well as the GO mixed SnS on heated substrates. The thin films were post-annealed under vacuum to form reduced graphene oxide. Structure, morphology and optoelectronic properties of thin films formed at various conditions were determined by different techniques. Scanning electron micrographs showed porous film surface with GO/rGO net-like structures embedded in SnS nanoparticles. Photocurrent measurements at different illumination wavelengths and cyclic voltammetry using SnS:rGO as working electrodes showed improvement in the properties of graphene oxide incorporated SnS. A solar cell was fabricated using SnS:rGO thin film and the results obtained are promising.

Optical and Electrical Properties of Copper Zinc Tin Sulfide Films As Solar Cell Absorber Materials Prepared by a Compacting Process

The copper zinc tin sulfide (CZTS) thin films are prepared by a promising non vacuum compacting process based on ball milling and coating technique. The results reveal that a well-formed crystalline structure of kesterite CZTS are observed after sintering at 450°C. The optical band gap is 1.49, 1.59, 1.33, and 1.21 eV for the films with Cu/Zn/Sn atomic radio of 1.00 : 0.50 : 0.52, 1.00 : 0.44 : 0.41, 1.00 : 0.60 : 0.49, and 1.00 : 0.49 : 0.58, respectively. The compacting process can further improve the performances of CZTS film. For the CZTS thin film with Cu/Zn/Sn atomic radio of 1.00 : 0.60 : 0.49, the surface morphology of the film is significantly improved by a compacting process applied to the coating films before sintering, and the resistivity decreased from 23.67 to 1.18 Ω cm with the compacting pressure increasing from 0 to 200 MPa at room temperature, which showing a promising application of the compacting process method in fabricating CZTS film for solar cells.

Effect of thermal annealing on nebulizer spray deposited tin sulfide thin films and their application in a transparent oxide/CdS/SnS heterostructure

Tin sulfide (SnS) thin film was deposited on glass substrates using simple nebulizer spray pyrolysis method. The influence of vacuum annealing on structural, optical, morphological, electrical and photovoltaic properties of the films were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, atomic force microscopy, energy dispersive analysis of X- ray, UV-Visible spectrophotometry, photoluminescence spectrofluorometry and Hall measurements. Structural parameters such as lattice structure, crystallite size, micro strain and dislocation density were estimated using XRD analysis. There was a notable enhancement in morphology and surface roughness of the films and they were found to vary with respect to the annealing temperature. Optical studies done on the films revealed a decrease in energy gap for the increase of annealing temperatures. From the Hall effect study, it was found that SnS thin films have p-type conductivity. The lowest resistivity and higher carrier concentration were found to be 0.074 Ω cm and 1.07 × 1019 (cm−3) respectively. A heterojunction solar cell, CdS/SnS was fabricated and its solar conversion efficiency obtained was about 0.73% for tin sulfide films annealed at 400 °C.

Effect of substrate temperature on the structural and optical properties of radio frequency sputtered tin sulfide thin films for solar cell application

Tin monosulfide (SnS) thin films were deposited on both soda lime glass (SLG) and Mo-coated SLG substrates by radio-frequency (RF) sputtering at a substrate temperature (Ts) from room temperature (RT) to 420 °C. The structural and optical properties were investigated by performing the scanning electron microscopy, electron dispersive spectroscopy, atomic force microscopy, X-ray diffraction, micro-Raman, and ultraviolet-visible-near infrared spectroscopy measurements. For Ts greater than RT showed the well-defined grain features with increased grain sizes. At 350 °C, the films showed the [S/Sn] ratio close to the stoichiometric SnS. The X-ray diffraction studies unveiled the orthorhombic crystal structure of SnS with the (111) preferred orientation for all the Ts. The Raman analysis confirmed the single phase of SnS without any secondary phases. The optical properties revealed a direct energy bandgap of SnS was around 1.2–1.4 eV and the bandgap decreased with increasing Ts. We fabricated the SnS/CdS heterojunction solar cell with the SnS grown at 350 °C. The device with a structure of SLG/Mo/SnS/CdS/i-ZnO/ITO/Ni/Ag exhibited the power conversion efficiency of 0.35% with an open-circuit voltage of 0.143 V, short-circuit current density of 6.7 mA·cm−2, and fill factor of 40.3%.

Effect of Ag doping on the physical properties of tin-sulfide thin films for optoelectronic applications prepared by spray pyrolysis

Silver-doped tin-sulfide thin films were deposited on glass substrates at 400 °C through spray pyrolysis. Afterward, the effects of Ag doping on the structural, optical, and electrical properties of thin films were investigated. The precursor solution was prepared by dissolving tin chloride (SnCl4∙5H2O) and thiourea (CS(NH3)2) in deionized water and subsequently adding silver acetate (AgC2H3O2). SnS2:Ag thin film was prepared with $$\frac{{\left[ {{\text{Ag}}} \right]}}{{\left[ {{\text{Sn}}} \right]}}$$ % of 1, 2, and 3 at.%. X-ray diffraction analysis showed that the thin film exhibited a preferred (001) orientation in the SnS2 phase, and the intensity of the (001) peak increased with increased Ag-doping concentration. In addition, scanning electron microscopy indicated that the thin films presented spherical grains. Increased doping concentration also resulted in a decrease in the single-crystal grain size from 14–6 nm, with an average grain size of 80–123 nm. Moreover, the optical bandgap decreased from 2.75 to 2.56 eV, and the carrier concentration decreased from 95.48 × 1015 cm−3 to 2.48 × 1015 cm−3. On the contrary, the Hall mobility increased from 59.725 to 183.28 cm2/v s. The electrical resistance also increased from 1.096 to 13.75 Ω cm. Hall effect studies revealed that the films exhibited n-type conductivity.

Characterization of single step electrodeposited Cu2ZnSnS4 thin films

Electrodeposited copper zinc tin sulfide (CZTS) thin films grown on conducting glass substrates are investigated in this report. The photoelectrochemical cell (PEC), optical, structural and morphological properties of the deposited films have been characterized. PEC measurements of the CZTS thin film showed p-type electrical conductivity. Optical measurement showed that the transmittance of CZTS films is observed to about 0.5–3.4% in the wavelength range 300–1100 nm. It is also observed that the absorbance of the CZTS thin films rapidly increases in the wavelength range 580–620 nm and then it decreases slowly. The band gap of the CZTS thin film is observed to be in the range 1.6–2.2 eV. The transmittance and band gap decreases upon annealing at different temperatures but the absorbance and the grain size increases due to the improvement of crystalline quality upon annealing. From the X-ray diffraction study, the CZTS films are found to be polycrystalline with (112), (200), (105), (204), (312), (220) orientations of the tetragonal structure. The average crystallite size is estimated to 23 nm for as-deposited film, 26 nm for annealed at 300 °C and 40 nm for annealed at 350 °C. It is found from SEM study that the precursor film shows non-uniform distribution of agglomerated particles with well-defined boundaries. As the annealing temperature increases, the crystallization of the films is observed to improve, and hence the morphology of as-deposited precursor film is observed to change into the larger flat grains upon annealing.