CZTS Phase Research Articles

Enhancement of structural & opt- electronic properties of vacuum processed Cu2ZnSnS4 thin film by thiourea treatment

Abstract In the present work, Cu-Zn-Sn-S precursor films were deposited by co-evaporation using elemental precursors. Prior to sulfurization, the precursor films were divided into three sets. Set1- Cu-Zn-Sn-S precursor directly sulfurized without any pre treatment, Set 2- Cu-Zn-Sn-S precursor film with an additional SnS layer deposited by thermal evaporation & sulfurized & Set 3 Precursor Cu-Zn-Sn-S film was treated with thiourea solution before sulfurization. From combined X-ray diffraction and Raman scattering analysis, CZTS phase formation was revealed for all three sets. Set 1 & Set 2 CZTS films exhibited SnS and CuS compounds as secondary phases while the set 3 film was found to have pure kesterite phase. Highly compact and uniform films were formed for all the three CZTS sets. Compositional analysis showed that the CZTS-TU film exhibit Cu-poor and Zn rich ratios while the rest two films showed slight deviations from ideal values. By employing glancing angle XRD technique, penetration depth values were calculated at four different incident angles. Phase, crystalline nature and micro structural parameters were evaluated for CZTS films at various incident angles. Best crystalline structure, morphology, compositions was obtained for the thiourea treated CZTS film.

Impact of Annealing Temperature on the Phase of CZTS with the Variation in Surface Morphological Changes and Extraction of Optical Bandgap

Quaternary CZTS (Cu2ZnSnS4) is an emerging alternative semiconductor material for solar cell technologies due to its earth abundancy, low cost and non-toxic nature. In addition, CZTS has a direct band gap of ∼1.5 eV which is the optimal value for converting the maximum amount of energy from the solar spectrum into electricity. The aim of the present study is to investigate the impacts of annealing temperature on the phase formation and morphological behavior of CZTS and material optical characteristics. X-ray Diffraction (XRD) reveals the single phase of kesterite CZTS that has been grown from the material precursors. Scanning electron microscope (SEM) shows the variation of morphological changes of CZTS with respect to annealing temperature. UV-Vis analysis confirms the optical band gap of 1.5 eV in the visible region which is suitable for photovoltaic applications.

Formation of sol-gel based Cu2ZnSnS4 thin films using ppm-level hydrogen sulfide

This study reports the preparation of copper zinc tin sulfide (Cu2ZnSnS4 or CZTS) thin films using parts-per-million (ppm) level of hydrogen sulfide (H2S) gas as opposed to high percentage level of H2S (e.g., ≥5%) in many other studies. Sol-gel technique was adopted for the preparation of metal oxide films from precursor solutions with different ratios of Cu, Zn, and Sn metal ions. Sulfurization process was carried out in tube furnace using 100ppm H2S balanced by hydrogen at different temperatures. Generally, it was observed that the sulfur content of the thin films obtained showed strong dependence on the sulfurization temperature. Samples sulfurized at higher temperatures (e.g., ~450 and 550°C) in ppm-level H2S experienced significant sulfur loss as confirmed by EDS, which was accompanied by the formation of metal alloys such as Cu3Sn as identified by XRD. On the other hand, samples sulfurized at lower temperatures of ~350°C and even 125°C revealed the formation of CZTS phase as confirmed by XRD, Raman micro-spectroscopy, and sheet resistance measurement. Moreover, local EDS analysis indicates that CZTS films prepared at those low temperatures have near-stoichiometric composition and are sometimes accompanied by the formation of Cu2−xS phase(s). In addition, stoichiometric and Cu-rich precursor solutions tend to yield CZTS samples with better crystallinity and superior optical properties compared with the Cu-deficient solution. These results are discussed from thermodynamics perspective and the directions for future research for safer and more economical processing of CZTS solar cells are pointed out.

Characteristics of Cu2ZnSn(SxSe1−x)4 thin-film solar cells prepared by sputtering deposition using single quaternary Cu2ZnSnS4 target followed by selenization/sulfurization treatment

This work demonstrates the preparation of Cu2ZnSn(SxSe1-x)4(CZTSSe) thin films by sputtering deposition using single-phase Cu2ZnSnS4 (CZTS) target followed by selenization/sulfurization treatment at 570°C for 1h. Afterward, the CZTSSe thin-film solar cell samples with the Mo/CZTSSe/CdS/i-ZnO/IZO/Al structure were prepared and their performances were evaluated. By varying the ratio of Se and S powders of heat treatment, the Cu-poor/Zn-rich CZTSSe layers with S/(S+Se) ratio in the range of 0.21–1 were achieved and the CZTSSe layers were the mixture of kesterite CZTS and CZTSe phases as revealed by the x-ray diffraction and the Raman spectroscopy analyses. UV-NIR spectroscopy indicated the bandgaps of CZTSSe samples are in the range of 1.06–1.45eV when the S/(S+Se) ratio varies from 0.21 to 1. Hall measurement observed the best transport property with p-type carrier concentration of 2.17×1015cm−3 and mobility of 8.9cm2V−1sec−1 in CZTSSe layer with S/(S+Se) ratio of 0.46. Under the AM1.5 illumination condition, the CZTSSe thin-film solar cell sample with S/(S+Se) ratio of 0.46 exhibited the best performance with open-circuit voltage of 0.506V, short-circuit current density of 27.41mA/cm2, fill factor of 50% and conversion efficiency of 6.9%.

First-principles investigation of the structural, dynamical, and dielectric properties of kesterite, stannite, and PMCA phases of Cu2ZnSnS4

${\mathrm{Cu}}_{2}{\mathrm{ZnSnS}}_{4}$ (CZTS) is a promising material as an absorber in photovoltaic applications. The measured efficiency, however, is far from the theoretically predicted value for the known CZTS phases. To improve the understanding of this discrepancy, we investigate the structural, dynamical, and dielectric properties of the three main phases of CZTS (kesterite, stannite, and PMCA) using density functional perturbation theory (DFPT). The effect of the exchange-correlation functional on the computed properties is analyzed. A qualitative agreement of the theoretical Raman spectrum with measurements is observed. However, none of the phases correspond to the experimental spectrum within the error bar that is usually to be expected for DFPT. This corroborates the need to consider cation disorder and other lattice defects extensively in this material.

Fabrication of CZTS thin films by dip coating technique for solar cell applications

Phase pure Cu2ZnSnS4 thin films were fabricated by simple dip coating technique. Precursor films were coated onto glass substrates using stable solutions of copper, zinc and tin dissolved in 2 methoxyethanol and monoethanolamine. These precursor films were sulphurized in N2+H2S atmosphere at different temperatures ranging from 400°C to 600°C. XRD analysis and Raman studies revealed a single CZTS phase for the films sulphurised at 500°C and 550°C, but good crystallinity was observed for the film sulphurized at 550°C. Rietveld method was used for structural refinement. SEM and FESEM studies indicate good surface morphology and large grains in the film sulphurized at 550°C. The film exhibited an optical absorption coefficient of >104cm−1 and an optical band gap of 1.4eV. The carrier concentration, resistivity and mobility are 1.434×1018cm−3, 5.3cm2/Vs and 0.828Ωcm, respectively and the conduction is p-type. The photovoltaic properties are suitable for thin film solar cell fabrication.

Effect of metal layer stacking order on the growth of Cu2ZnSnS4thin films

In this paper we have presented an in-depth study of effect of metallic precursor stacking order on the growth of the Cu2ZnSnS4 (CZTS) thin films. The CZTS films were prepared by employing a two-step process comprising of sequential sputtering of the metal precursors followed by sulfurization. An optimized stacking sequence as well as growth mechanism for obtaining the single phase CZTS has been proposed based on the results of XRD, Raman, XPS, UV–Vis and electrical studies. A combination of Raman analysis and XPS has been carried out to confirm the CZTS phase formation and to detect any minor phases, if present. The occurrence of Raman modes at around 286 and 336cm−1 for the Zn/Cu/Sn/Cu stack sulfurized at 500°C indicated the existence of prominent Kesterite CZTS phase. The perfect homogeneous mixing of sequential precursors together with the elemental sulfur was observed in the case of sulfurized stack order of Zn/Cu/Sn/Cu, which yielded single phase CZTS films, and further confirmed by high resolution core level XPS measurements. Stack dependent micro structural features and elemental analysis were also carried out using FESEM attached to EDS. The p-type charge carriers as detected using hot-probe measurement technique and the band-gap energy of ∼1.52eV as estimated from the absorbance spectrum, suggested that the Zn/Cu/Sn/Cu stack order is most appropriate for realizing single phase CZTS growth using two step method.

Phase evolution pathways of kesterite Cu2ZnSnS4 and Cu2ZnSnSe4 thin films during the annealing of sputtered Cu-Sn-Zn metallic precursors

The formation of secondary phases in kesterite-based solar cells plays a critical role, affecting the performances of devices primarily due to the open circuit voltage deficient characteristics. Systematic studies of the phase evolution pathways and the formation of secondary phases in kesterite thin films are desirable. In this paper, the phase evolution pathways and the formation of secondary phases in kesterite Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) thin films during thermal treatment of sputtered Cu-Sn-Zn metallic precursors have been studied using high-resolution X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). A possible phase evolution process for the kesterite thin films is proposed based on the experimental observations. The Cu-Sn-Zn metallic precursor thin films were prepared using the sputtering technique followed by thermal treatments at different temperatures ranging from 250°C to 580°C in a chalcogen atmosphere. XRD and Raman characterizations of the thin films annealed under chalcogen atmospheres indicated that the precursor thin films were completely transformed to the CZTS and CZTSe kesterite phases above 500°C. However, the TEM analysis of the thin films annealed above 450°C revealed Cu-based secondary phases. The formation of phase pure CZTS and CZTSe kesterites was observed at annealing temperatures above 500°C. Based on the experimental observations, the phase evolution pathways for the formation of kesterite and secondary phases from metallic precursors are proposed in this paper.

Formation mechanism of secondary phases in Cu2ZnSnS4 growth under different copper content

Understanding the formation mechanism of the secondary phases in Cu2ZnSnS4 (CZTS) absorber layer is necessary for the development of CZTS thin films solar cells. With this aim, the XRD, Raman and SEM were used to investigate the phases coexistence in CZTS thin films grown under different copper content. The surface of the Cu-rich CZTS thin films is rough, and the secondary phase CuxS emerges as front surface phases. Besides, another secondary phase ZnS segregates towards both front and back regions of off-stoichiometric CZTS thin films (Cu rich or Cu poor), which was evidenced by the 2nd and 3rd order of ZnS using Raman analysis excitated at 325nm. The pure phase CZTS exists only as its composition was stoichiometric. So the preparation of pure phase CZTS is sensitive to composition, suggesting that the precise composition control plays an important role in CZTS growth.

Photoelectrochemical CO2 reduction By Using Different Buffer Layers (In2S3, CdS) -Decorated Cu2ZnSnS4

Introduction Since atmospheric CO2 levels have been on the rise, global warming has become a serious problem. Recently, photoelectrochemical (PEC) CO2 reduction has attracted considerable attention as a potential means of converting solar energy into chemical energy in the form of usable organic fuels such as carbon monoxide, hydrocarbon, alcohol, and so on. To achieve the PEC CO2 reduction, the development of photocathode which possess a high energy-conversion efficiency and a high chemical stability, are strongly demanded. Cu2ZnSnS4 (CZTS) has attracted much attention as a thin film photocathode due to their specific characteristics: p-type semiconductor, high stability, ability to promote H2 evolution in response to visible light irradiation. In the present study, we fabricated CZTS photocathode by sol-gel method, and evaluated its PEC CO2 reduction properties under visible light irradiation. Moreover, we introduce n-type semiconductors (CdS, In2S3, etc.) as suitable buffer layer of the CZTS photocathode to improve the photocurrent response and selectivity of CO2 reduction. Experimental The CZTS photocathode was fabricated by sol-gel/spin-coated method on a molybdenum coated soda-lime glass (Mo/SLG) substrate. The precursor sol was prepared by dissolving raw materials (Cu2(CH3COO)2, SnCl2, Zn(CH3COO)2 and CH4N2S) into 2-methoxyethanol. Moreover, monoethanolamine was added into the prepared solution to avoid cracks during spin coating, resulting that the precursor sol was obtained. The precursor sol was spin coated on Mo/SLG substrate and annealed at 200 ℃ for 5 min on a hotplate. After this process had been repeated for a maximum of 5 times, the electrode was calcined in sulfur/N2 atmosphere. Then the CZTS photocathode was obtained. Surface modification of the CZTS photocathode was performed by chemical bath deposition (CBD) method. The CZTS photocathode was soaked in the bath solution containing raw materials for producing n-type semiconductors, and then annealed in air. Then surface modified CZTS photocathode could be prepared. The crystalline phase of CZTS was characterized by using a powder X−ray diffraction (XRD) instrument, and Raman spectroscopy. The PEC properties of the CZTS photocathode was investigated in a closed three-electrode configuration using a Ag/AgCl reference electrode and a Pt coil counter electrode. The electrolyte was 0.1 M NaHCO3 solution. The electrolyte was stirred and purged with CO2 gas for 40 min before measurement. The PEC CO2 reduction was investigated by using Xe lamp (420 < λ < 800 nm, 100 mW cm-2). The CO2 reduction products were evaluated by using gas-chromatography and ion chromatography. Results and Discussion The XRD pattern of the CZTS photocathode on Mo/SLG substrate composed of three peaks located at 28.1ﾟ, 47.0ﾟ, and 55.8ﾟ,which corresponds to (112), (220), (312) phase of kesterite structure of CZTS. For the raman spectrum, main sharp peak was observed at 336 cm-1 which ascribed to the kesterite structure of CZTS. These results indicated that the CZTS thin film could be prepared by sol-gel/spin-coating method. The morphology of CZTS thin film and surface-modified CZTS thin films were investigated by cross sectional SEM: flat and uniform films were observed. UV-vis spectrum has an absorption edge at around 830 nm, which corresponding to the optical absorption edge of the CZTS. The photocurrent of CZTS photocathode was dramatically enhanced by surface modification of n-type semiconductor layers due to efficient separation of the charge carriers at n-type/CZTS semiconductor interface (p-n heterojunction). The highest photocurrent was obtained from CdS/CZTS electrode because conduction band offset between CZTS and CdS was smaller than the other n-type layers. As a result of CO2 reduction product analysis, CO and HCOOH were obtained. Moreover, selectivity for CO2 reduction was improved by surface modification of CZTS photocathode: when CdS was deposited on the CZTS, the CO generation was increased. On the other hands, In2S3 was deposited, the HCOOH generation was increased. The detailed information will be discussed in poster session.

Electrical conduction noise and its correlation with structural properties of Cu2ZnSnS4 thin films

Cu2ZnSnS4 (CZTS) thin films have been deposited by ultrasonic assisted chemical vapor deposition in a single step process at different substrate temperatures and structural, morphological, electrical and conduction noise characteristics of the CZTS thin films have been studied. Single phase CZTS thin films are formed at 275 °C and 325 °C deposition temperatures, whereas the CZTS thin film deposited at 375 °C showed secondary phase also. The crystallinity of the films improves and resistivity decreases with the increases of the deposition temperature. The temperature dependent electrical conductivity of the films reveals that in the temperature range 300–250 K, thermally activated conduction is observed. The conduction noise in the CZTS thin films, exhibits 1/f noise in the low frequency region and found to be strongly dependent on the film deposition temperatures. The film deposited at 275 °C and 375 °C shows larger conduction noise, whereas the film deposited at 325 °C shows smaller noise. For the low frequency 1/f noise, the value of α is also found to be the minimum for the film deposited at 325 °C. The higher value of conduction noise in the film deposited at 275 °C is related to poor crystallinity and less compact morphology. For the film deposited at 375 °C, crystallinity and compactness improves, but the presence of the secondary phases seems to be responsible for generating higher noise. The smallest conduction noise of the film deposited at 325 °C is due to single phase film with better crystallinity and smaller trap density ∼5.1 × 1015 cm−2 eV−1.

Tailoring the properties of Cu2ZnSnS4 thin films grown by ultrasonic spray pyrolysis

Cu2ZnSnS4 (CZTS) thin films are grown using an automated ultrasonic spray pyrolysis setup. Sn concentration is varied to attain properties suitable for solar cell applications. Kesterite tetragonal structured CZTS phase is dominant in all films. When Cu/(Zn+Sn)>0.83, films showed Cu2S phase in addition to CZTS phase. Film is nearly stoichiometric when Cu/(Zn+Sn) concentration ratio in the precursor solution is 1.07. When Sn concentration is reduced, Cu concentration increases proportionally and a significant change in morphology occurred for the Cu-rich films. All the samples are p-type in nature and their resistivity varies between 255 and 0.9×10−3ohmcm. Sample with Cu/(Zn+Sn) ratio of 0.83 is found to be suitable for solar cell applications.

CZTS absorber layer for thin film solar cells from electrodeposited metallic stacked precursors (Zn/Cu-Sn)

In the present work, Kesterite-Cu2ZnSnS4 (CZTS) thin films were successfully synthesized from stacked bilayer precursor (Zn/Cu-Sn) through electrodeposition-annealing route. Adherent and homogeneous Cu-poor, Zn-rich stacked metal Cu-Zn-Sn precursors with different compositions were sequentially electrodeposited, in the order of Zn/Cu-Sn onto Mo foil substrates. Subsequently, stacked layers were soft annealed at 350°C for 20min in flowing N2 atmosphere in order to improve intermixing of the elements. Then, sulfurization was completed at 585°C for 15min in elemental sulfur environment in a quartz tube furnace with N2 atmosphere. Morphological, compositional and structural properties of the films were investigated using SEM, EDS and XRD methods. Raman spectroscopy with two different excitation lines (514.5 and 785nm), has been carried out on the sulfurized films in order to fully characterize the CZTS phase. Higher excitation wavelength showed more secondary phases, but with low intensities. Glow discharge optical emission spectroscopy (GDOES) has also been performed on films showing well formed Kesterite CZTS along the film thickness as compositions of the elements do not change along the thickness. In order to investigate the electronic structure of the CZTS, Photoluminescence (PL) spectroscopy has been carried out on the films, whose results matched up with the literatures.

Solution-grown near-stoichiometry Cu2ZnSnS4 films: Optical transitions and defect levels

The preparation of device quality Cu2ZnSnS4 (CZTS) films by a simple and low-cost technique is of great importance for photovoltaic applications. In this work, stoichiometric films of CZTS could be synthesized by a successive dip coating method using a non-toxic methanol-based solution. The films' structure, composition, and surface morphology were studied by standard techniques. CZTS/CdS diodes with high rectification factors were fabricated and were used for electrical characterization of the films. The optical transmittance and photocurrent measurements were performed for optoelectronic characterization of the films. The results revealed the presence of two acceptor-type native defects with the activation energies of 114 meV and 300 meV. Five optical transitions were detected in the energy range of 1.34–3.2 eV and all could be identified on the basis of the two measured defect levels and the theoretical band diagrams of the stannite and kesterite structural phases of CZTS reported by Botti, Kammerlander, and Marques (2011). The results were in support of the co-existence of both structural phases in the films.

Impact of pre-alloying of sputtered Cu/Sn/Zn precursors for Cu2ZnSnS4 thin films

The Cu2ZnSnS4 (CZTS) films were prepared by sulfurizing the sputtered Cu‒Sn‒Zn precursors. The precursors were fabricated by sequentially sputtering of Cu, Sn and Zn metallic layers onto Mo-coated glass substrate. The effects of alloying before sulfurization on the structural and optical characteristics of the CZTS films were presented. Two independent sulfurization processes were carried out and compared. The sulfurization of the reference was completed in the tube furnace at 550°C for 2h. In the two-stage heat treatment approach, the precursor was alloyed at various temperatures before the sulfurization. Experimental results showed that alloying at 170°C was crucial to improve the CZTS films, yielding uniform and dense grains with single kesterite CZTS phase.

A mechanochemical route to single phase Cu2ZnSnS4 powder

With respect to absorber materials in solar cells, Cu2ZnSnS4 (CZTS) has been a focus of interest in recent years. In this work, a new route leading to single phase CZTS powders is presented. For structural characterization X-ray and neutron powder diffraction measurements were performed. Further structural and compositional analysis of the CZTS powder was carried out by means of X-ray absorption near edge spectroscopy (XANES) and wavelength-dispersive X-ray spectroscopy (WDS). The obtained CZTS powder with an actual composition of Cu2.00(4)Zn1.02(2)Sn0.99(2)S4.00(8) adopts the kesterite-type structure. A detailed cation distribution analysis using the average neutron scattering length method revealed a partial disorder of copper and zinc on the (2c) and (2d) sites.

Effect of sulfurization time on properties of Cu2ZnSnS4 thin films obtained by sol–gel deposited precursors

As a promising and alternative solar absorber material, the Cu2ZnSnS4 (CZTS) has gained a broad interest over recent years due to its excellent material properties such as suitable and tunable band gap energy of 1.4–1.6 eV and absorption coefficient over 104 cm−1 (Jimbo et al. in Thin Solid Films 515(15):5997–5999, 2007; Katagiri et al. in Sol Energy Mater Sol Cells 65(1–4):141–148, 2001). In addition, all components of the CZTS are naturally abundant and non toxic. Nowadays solution based-approaches are being developed for the deposition of CZTS to overcome the problem of expensive and complicated vacuum-based methods. In this work, we report the study of properties of the novel wurtzite CZTS material prepared by sol–gel sulfurization as a function of annealing time. The effect of annealing time on structural and optical properties of the films was investigated. The X-ray diffraction analysis confirmed the formation of the wurtzite CZTS phase. The crystallinity of the films increases with an increasing sulfurization time. The values of the optical absorption coefficients for the film were found to be 104 cm−1. The optical band-gap values were estimated to be between 1.58 and 1.79 eV depending on the sulfurization time.

Pulsed electrodeposition of Cu2ZnSnS4 absorber layer precursor for photovoltaic application

Cu2ZnSnS4 (CZTS), comprising of earth abundant and non-toxic elements, is an ecofriendly and cost effective thin film absorber layer for solar cell applications. The present work describes the fabrication of p-type absorber material Cu2ZnSnS4 (CZTS) from alkaline pyrophosphate solution through pulsed electrodeposition (PED) at room temperature. CZTS thin film is prepared from one step co-electrodeposited Cu–Sn–Zn (CZT) precursor film obtained from pyrophosphate bath under potentiostatic condition (−1.4V) onto a Ni substrate followed by annealing in sulfur atmosphere at 500°C for 1h and 30min. To achieve the desired CZTS stoichiometry in the deposited material, applied potential for the co-deposition has been calculated from the Tafel plots. The crystallographic phases, morphology and composition of the electrodeposited Cu–Sn–Zn precursor and the sulfurized films are assessed through X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. Formation of CZTS phase is confirmed from X-ray diffraction and Raman spectroscopy of the sulfurized sample. Optical band gap measurement is investigated by using UV–Vis absorption spectroscopy. The CZTS thin film of kesterite structure is obtained with a band gap of 1.5eV, which is suitable for solar cell fabrication.

Investigation of the role of sodium in Cu2ZnSnS4films and the resulting phase evolution during sulfurization

Kesterite Cu2ZnSnS4 (CZTS) is one of the most attractive materials in future photovoltaics. However, copper could accumulate at the surface of CZTS films causing the combination of carriers and short circuiting of solar cells. One possible solution is sodium doping. In this paper, in order to investigate the role of sodium in CZTS phase distribution and segregation, a series of experimental works were carried out with Na-containing and Na-free samples. From the analyses of X-ray photoelectron spectra (XPS) and Raman spectra, sodium was found to accumulate near the surface and interface, where Zn-rich regions were also detected. To explain this phenomenon, we deduced that sodium plays an important role in Zn accumulation and contributes to the surface and interface modifications. Based on this deduction, we conducted a detailed phase reaction process on samples containing a 40 nm NaF layer annealed at various temperatures. The phase evolution route was confirmed and the results gave us a better understanding of the role of sodium in CZTS evolution.

Effect of initial bath condition and post-annealing on co-electrodeposition of Cu2ZnSnS4

Polycrystalline Cu2ZnSnS4 thin films were electrodeposited on Mo and F:SnO2/Glass substrates at room temperature by single step method from an aqueous solution containing tri-sodium citrate and tartaric acid as complexing and pH controlling agents, respectively. The thermostatic bath deposition was carried out at room temperature (25 °C) with lower and higher initial concentrations of Cu, Zn, Sn and S- precursors in order to investigate the effect of stoichiometric deviations on their phase compositions and optoelectronic properties. As-prepared samples were photoactive as revealed by photo electrochemical (PEC) measurement, however, it showed the films were mixture of p- and n-type semiconducting phases. The post-annealing treatment was carried out in the temperature range 400–600 °C in an Ar-atmosphere to improve the CZTS phase composition and crystallinity of the film. The kesterite Cu2ZnSnS4 phase with preferred orientation along the (112) crystal direction grew to greater extent upon Ar-annealing at 500 °C associated with an improvement in the optical band gap. The PEC cells made from the annealed film showed an enhanced photocurrent response with p-type conductivity.