Properties Of Cu2ZnSnS4 Thin Films Research Articles

Study some Electrical Properties of Cu2ZnSnS4 Thin Films Prepared by Pulse Laser Deposition

Study some Electrical Properties of Cu2ZnSnS4 Thin Films Prepared by Pulse Laser Deposition

Impact of solution flow-rate on the microstructure and optoelectronic properties of Cu2ZnSnS4 thin films deposited via ultrasonic spray method

Cu2ZnSnS4 (CZTS) thin films were synthesized on glass substrates via ultrasonic spray pyrolysis method to investigate the influence of solution flow-rate on their physical properties. Solution flow-rate was varied in the range of 10–30 ml/h to analyse its impact on the films. XRD analysis revealed a kesterite phase with a preferred orientation along the (112) plane, which intensified with higher flow-rates. Additionally, structural investigations identified secondary phases of CuxS, Sn2S3, and Cu2SnS3 in the films prepared at a solution flow-rate of 25 ml/h. Raman spectroscopy confirmed the XRD analysis. SEM micrographs indicated compact growth with a slightly rough surface. UV–Vis spectroscopy demonstrated a significant decrease in transmittance, leading to a corresponding reduction in the bandgap value from 2.17 to 0.84 eV as the flow rate increased from 10 to 30 ml/h. The electrical conductivity analysis indicated p-type conductivity, with maximum conductivity value of 2.73 (Ω cm)−1 observed at a flow-rate of 20 ml/h.

Investigating the effects of bismuth doping on the structural, optical, and electrical properties of Cu2ZnSnS4 thin films for photovoltaic applications

Investigating the effects of bismuth doping on the structural, optical, and electrical properties of Cu2ZnSnS4 thin films for photovoltaic applications

Tailoring the electrical properties of Cu2ZnSnS4 thin film by heterovalent Al3+ doping

Kesterite Cu2ZnSnS4 (CZTS) thin film is an attractive photovoltaic material. Harmful vacancy and anti-site defects in CZTS can be reduced by equivalent doping. However, equivalent doping leads to a reduction in the carrier concentration that is essential to the built-in electric field and built-in potential of the device. In this work, we propose heterovalent Al doping to provide hole conduction in CZTS thin film. The chemical valence of doping cation Al3+ is different from that of the substituted cation Sn4+. Al-doped CZTS thin films were fabricated by magnetron sputtering and sulfurization. The Al content was controlled by the Al sputtering time of the precursor. The experimental results revealed the successful fabrication of heterovalent Al-doped CZTS with the preferred orientation of the (112) plane. The partial substitution of Sn by Al led to a right shift of the CZTS diffraction peaks. Al doping could improve the crystalline quality of CZTS, reduce the dislocation density and microstrain of CZTS, and enhance the compactness of the thin-film surface. With the increase in Al content, the distance decreased between the Fermi level and the valence band maximum of CZTS, and the hole concentration and conductivity of CZTS increased monotonously while the non-radiative recombination of carriers was suppressed. The conductivity of CZTS reached 1.47 × 102 S/cm. Therefore, heterovalent Al doping was found to be a useful method to regulate the electrical properties of CZTS thin film.

Optimization of electrodeposition time on the properties of Cu2ZnSnS4 thin films for thin film solar cell applications

The Electrochemical deposition was used to create a quaternary CZTS (Cu2ZnSnS4) kesterite thin layer. An aqueous solution of CZTS was used to deposit a thin layer over Indium Tin Oxide. The effects of deposition time (variation) on CZTS thin films under ambient conditions were investigated in this study. Several available characterization systems were used to study the samples as they were produced. The polycrystalline description of the layer is investigated by X-ray diffraction. The SEM as well as AFM study show that the deposition time improved surface morphology and topography of CZTS thin films which increase several nm in grain size. Furthermore, depending upon the deposition duration that affect the thickness and crystallinity of the films prepared, the optical study reveals an acceptable band gap in a range of 1.71–1.42 eV. Characteristics of high-quality CZTS absorber layers for solar cell applications are determined by deposition time variation. To check the effect of this band gap variation (1.71–1.42 eV, depending upon the deposition time) on the performance of a CZTS based thin film solar cell, a simulation software SCAPS-1D is being used.

Structural, optical and electrical properties of Cu2ZnSnS4 thin film deposited by electron beam evaporation method

In this research work, the Cu2ZnSnS4 (CZTS) powder was synthesized using microwave-assisted technique. Sandwich device of Al/ CZTS /Al thin film was deposited by electron beam gun evaporation method (EBG). The optical and structural properties of CZTS have been investigated using UV–visible optical absorption, scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The XRD pattern confirmed the formation of kesterite structure for CZTS. SEM micrograph revealed the crystalline and porous surface characteristic of CZTS thin film. The CZTS particles have band gap energy 1.6 eV that was determined by UV–visible. In order to specify the dominant conduction mechanism, AC conductivity of CZTS thin film was measured at different temperatures and frequencies (290 K<T < 410 K and 102 Hz <f< 105 Hz). At the temperature range from 290 K to 410 K for 104 Hz <f< 105 Hz, hopping is the dominant conduction. The exponent s values (from 0.67 to 0.86) confirm the hopping mechanism in accordance with Jonscher law, also.

Enhancement of photoelectric properties of Cu2ZnSnS4 thin films by electronic excitations induced by swift heavy ions

The structural, optical, and current–voltage characteristics including photosensitivity of copper zinc tin sulphide (Cu2ZnSnS4) thin films were modified significantly by the electronic excitations. These excitations were induced by swift heavy ion (SHI) beams of 100 –120 MeV of O, Ag, and Au. X-ray diffraction patterns confirm that the pristine and irradiated films crystallize in kesterite structure and the crystallite size increases after O, and Ag ion irradiations compared to Au ions. The micro-Raman spectra reveal the presence of lattice defects in the Au irradiated sample. The analysis shows that the crystallinity of the Cu2ZnSnS4 thin film increases with O ion irradiation indicating that the density of defect states decreases after SHI irradiation. The maximum photosensitivity is found to be 62% for O irradiated thin films compared to other ion beams due to the reduction in the band gap.

Study on the physical properties of Cu2ZnSnS4 thin films deposited by pneumatic spray pyrolysis technique

The acquisition of new materials for the manufacturing of high efficiency and low-cost photovoltaic devices has currently become a challenge. Thin films of CuInGaSe and CdTe have been widely used in solar cell of second generation, achieving efficiencies about 20 %; however, the low abundance of In and Te as well as the toxicity of Cd is the primary obstacles to their industrial production. Compounds such as Cu2ZnSnS4, Cu2ZnSnSe4 and Cu2ZnSn(SSe)4 have emerged as an important and less costly alternative for efficient energy conversion in the future. In addition, these compounds have the required characteristics to be used as an absorber material in solar cells (band-gap close to 1.4 eV, an absorption coefficient greater than 104 cm-1 and a p-type conductivity). In this work, we present a study of the structural, compositional, morphological and optical properties of Cu2ZnSnS4 thin films deposited by spray pyrolysis technique as well as their dependence on temperature.

Effect of volume of the solution and sulfurization on properties of Cu2ZnSnS4 thin films fabricated by spray assisted chemical vapour deposition method

ABSTRACT Cu2ZnSnS4 thin films were produced by spray assisted chemical vapor deposition process (SACVD) technique using different volumes of aqueous ionic solution, followed by sulfurization in sulfur vapors at 500°C and under Argon atmosphere. These CZTS thin films were analysed by X-ray diffraction and Raman scattering analysis that have confirmed the kesterite phase structure of CZTS films before and after sulfurization. The optimum band gap of the as-deposited CZTS films are between 1.40 and 1.43 eV. The cristallinity of the layers improve after sulfurization and their band gap varies between 1.44 and 1.50 eV. The surface morphology of the samples was examined by scanning electron microscopy. The chemical composition was determined by energy dispersive X-ray spectroscopy which shows the formation of Cu poor and Zn rich sulfurized CZTS thin films. Hall Effect measurements revealed that all the films before and after sulfurization are p-type. The sulfurized films obtained in our laboratory have carrier concentrations ranging from 3.1 to 6.8 x 1018 cm-3, a resistivity between 0.199 and 0.262 Ω.cm and mobility between 3.5 and 10.1 cm2/V.s.

Study of the semiconducting properties of Cu2ZnSnS4 thin films grown by ultrasonic spray pyrolysis of water-dissolved precursors

Cu2ZnSnS4 (CZTS) thin films were deposited on glass-slide substrates by ultrasonic spray pyrolysis at the substrate temperatures in the 330–420 °C range, using water–ethanol solutions containing CuCl2–H2O, ZnCl2, SnCl2, and (NH2)2CS (thiourea). After being deposited, CZTS films were annealed under vacuum and then characterized in regarding their structural and optical properties. The X-ray diffraction and Raman spectroscopy studies indicated that CZTS thin films with kesterite as predominant phase could be obtained. The X-ray diffraction patterns of all deposited samples displayed diffraction peaks corresponding to the planes (112), (220), and (312) of kesterite CZTS and diffraction peaks belonging to phases other than CZTS were apparently undetectable for the X-ray technique. Furthermore, their Raman spectra were featured for a widely structured Raman band in the 200–400 cm−1 wavenumber area. After being deconvoluted, Raman peaks belonging only to kesterite CZTS were revealed. However, a further analysis of the UV–Vis absorbance spectra indicated all our films strongly absorbs in this spectral region. In the low photon energy region (< 1.5 eV), Tauc plots revealed electron transitions with characteristic energy values in the 1.15–1.34 eV range, which could be attributed at the presence of tetragonal Cu2SnS3 and point defects (VS and VZn) into CZTS. All prepared CZTS films display the p-type conductivity as verified by Hall measurements.

Correlation of thermoelectric properties of Cu2ZnSnS4 thin films grown by the chemical solution method with sulfur concentration

The current study focused on the improvement of thermoelectric properties of Cu2ZnSnS4 (CZTS) thin films grown by the chemical solution method by our engineering other secondary phases. The density of copper mono-sulfides (CuS) related secondary phases was controlled by our varying the molar concentration of sulfur during the growth process. Data from thermoelectric studies suggested that the Seebeck coefficient, electrical conductivity, and power factor were increased from 148 to 393 μV/°C, from 18.51 to 76 S/cm, and from 4.05 × 10−5 to 1.17 × 10−3 W/m K2, respectively, as the concentration of sulfur atoms increased from 2 to 8 mM. This huge improvement in thermoelectric properties was linked to the development of CuS-based secondary phases due to extra sulfur atoms in the CZTS crystal. For verification of secondary phases, we used a number of characterization techniques, such as X-ray diffraction (XRD), conductivity measurements, Raman spectroscopy, photoluminescence spectroscopy, UV/vis spectroscopy, and scanning electron microscopy measurements. The XRD data verified the tetragonal structure of the CZTS thin films, and the crystalline size was found to decrease as the sulfur content increased. It is also demonstrated by the XRD data that CuS-based secondary phases started to develop for the samples with higher molar concentration of sulfur along with intensity reduction of the CZTS peaks. The vibrational modes of CZTS thin films were also confirmed by Raman spectroscopy with 288 and 334 cm−1 A1g, 350 cm−1 B (TO), and 367 cm−1 B (LO) lattice vibrational modes. However, the Raman peak intensity of sulfur-based secondary phases such as CuS, Cu2S CuxS, and Cu2-xS was found to increase with increasing concentration of sulfur. Scanning electron microscopy images of CZTS thin films showed that the sample prepared with a sulfur concentration of 8 mM has a rough surface as compared with samples prepared with a lower concentration of sulfur The UV/vis spectroscopy data suggest that the band gap of CZTS thin films decreased from 2.19 to 1.91 eV as the concentration of sulfur atoms increased from 2 to 8 mM. Photoluminescence measurements also supported our argument.

Influence of Sulfurization Time on the Properties of Cu2ZnSnS4 Thin Films Deposited on Mo-coated Soda Lime Glass Substrates by Co-sputtering Technique

In this work, Cu2ZnSnS4 (CZTS) absorber films were prepared by sulfurization of co-sputtered precursor films at different time periods. The influence of sulfurization time on physical characteristics of the grown films was investigated in detail. The sulfurized CZTS films exhibited the characteristic diffraction peak of the kesterite phase corresponding to the (112) crystal plane, the main Raman mode of kesterite phase at around 337 cm−1 and Cu-deficient and Zn-rich composition. From the atomic force microscopy surface and cross-sectional scanning electron microscopy images, it was revealed out that the films were uniform, compact without any cracks and consisted of micron-sized and closely packed grains. In addition, the films showed tail-to-tail, band-to-tail and band-to-band transitions at around 1.41 eV (E1), 1.45 eV (E2) and 1.51 eV (E3), respectively. Secondary ion mass spectroscopy analysis showed that the sodium ions deeply diffused through the molybdenum layer into the CZTS film from the soda lime glass substrate for all samples. All of the films exhibited an optical band gap of around 1.4 eV, an absorption coefficient over 104 cm−1, p-type conductivity with a high concentration of free holes in the order of 1017-1018 cm−3 and low mobility in the range from 0.63 cm²/V.s to 8.11 cm²/V.s.

Fabrication of Ag and Mn Co-Doped Cu2ZnSnS4 Thin Film.

Ag and Mn dopants were incorporated into Cu2ZnSnS4 thin film to reduce defects in thin film and improve thin film properties. Sol–gel and spin-coating techniques were employed to deposit Ag and Mn co-doped Cu2ZnSnS4 thin films. The structures, compositions, morphologies, and optical properties of the co-doped thin films were characterized. The experimental results indicate the formation of kesterite structure without Ag and Mn secondary phases. The amount of Ag in the thin films is close to that in the sols. The co-doped Cu2ZnSnS4 thin films have an absorption coefficient of larger than 1.3 × 104 cm−1, a direct optical band gap of 1.54–2.14 eV, and enhanced photoluminescence. The nonradiative recombination in Cu2ZnSnS4 thin film is reduced by Ag and Mn co-doping. The experimental results show that Ag and Mn incorporation can improve the properties of Cu2ZnSnS4 thin film.

EFFECT OF POTASSIUM CYANIDE ETCHING ON STRUCTURAL, OPTICAL AND ELECTRICAL PROPERTIES OF Cu2ZnSnS4 THIN FILMS DEPOSITED BY A MODIFIED SPRAY PROCESS

We report the effect of potassium cyanide etching treatment on structural, optical and electrical properties of Cu2ZnSnS4 thin films prepared by a spray-assisted chemical vapor deposition process. Raman spectroscopy and X-ray diffraction measurements before and after potassium cyanide etching have confirmed the kesterite structure of Cu2ZnSnS4 films. Potassium cyanide treatment led to the elimination of [Formula: see text]S secondary phase. Optical measurements showed that the band gap value was about 1.52[Formula: see text]eV. The best electrical resistivity and Hall mobility values were reached for a deposition temperature of 450∘C in both cases without and with potassium cyanide treatment.

Correction to: Effect of film thickness on structural, morphological, and optical properties of Cu2ZnSnS4 thin films prepared by sol–gel spin coating

The author found a spelling mistake in reference no. 46.

Structural and Optical Properties of Cu2ZnSnS4 Films Prepared by Sol-Gel method

Chest x-ray medical images are widely used for diagnostic purposes for Cu2ZnSnS4 thin films are prepared by sol gel and spin coating methods. In this study, some physical properties such as structural and optical properties of Cu2ZnSnS4 thin films are investigated. Prepared thin films are annealed at 400°C for 1 h under N2 atmosphere. XRD pattern for the peaks 28.31°, 47.26°, and 56.12° which have indexed plans (112), (220) and (312) confirmed that all Cu2ZnSnS4 thin films prepared have kesterite structure. The results of XRD patterns and UV– Visible spectra demonstrated kesterite phase and a great optical absorption coefficient more than 105­ cm-1 in visible region. The estimation of the band gap which equal Eg ≈ 1.5 eV by dependent at the optical characteristics.

Structural, optical and Schottky diode properties of Cu2ZnSnS4 thin films grown by two-stage method

CZTS thin film was prepared by a two-stage process comprising sputter deposition of metallic Cu, Zn, and Sn layers followed annealing treatment of the metallic precursors in a sulfur atmosphere at 560 °C for 3 min. The CZTS thin film was investigated in the way of structural, optical and electrical properties. The XRD pattern of Cu-poor and Zn-rich CZTS thin film was dominated by characteristic peaks of kesterite CZTS planes. Raman spectra of the film ensured formation of kesterite CZTS phase and displayed formation of CTS and ZnS phases. Dense and polycrystalline surface features were observed in SEM images of CZTS thin film. Band–band transitions was not observed due to the probable concentration of deep acceptor levels in this material. The diode parameters of Mo/CZTS/Al structure such as ideality factor, barrier height and serial resistance were calculated employing temperature dependent I–V characteristics of Mo/CZTS/Al diode structure.

Effect of film thickness on structural, morphological, and optical properties of Cu2ZnSnS4 thin films prepared by sol–gel spin coating

Effect of film thickness on structural, morphological, and optical properties of Cu2ZnSnS4 thin films prepared by sol–gel spin coating

Influence of pre-sulfurization temperature on properties of Cu2ZnSnS4 thin film in two-step sulfurization process

In this study, Cu2ZnSnS4 (CZTS) thin films were prepared by magnetron sputtering deposition of the Cu-Zn-Sn metallic precursor (CZT) on flexible molybdenum foils and a two-step sulfurization process. Low-temperature pre-sulfurization was performed before the final high-temperature sulfurization during the two-step sulfurization process to enhance the properties of CZTS. This paper presents a method to improve the properties of CZTS thin films, making them conducive to solar cell applications. The compositions and morphologies of CZTS were confirmed using energy dispersive spectroscopy and scanning electron microscopy, respectively. X-ray diffraction was conducted to investigate the structural properties of the CZTS thin films, and the results revealed that the CZTS phase in all the samples had a preferential plane along (112). Moreover, Raman spectroscopy helped distinguish the ZnS and Cu2SnS3 phases that are close to kesterite CZTS. Compared to the thin film prepared without pre-sulfurization treatment, a suitable increase in pre-sulfurization temperature could reduce the loss of Sn and enhance the crystallinity of CZTS. However, a higher pre-sulfurization temperature could result in the formation of secondary phases. The CZTS thin films exhibited good properties when the CZT precursor was pre-sulfurized at 150 °C. In addition, the CZTS thin films had a single phase and flat and dense surfaces with large grains. The optical parameters were calculated based on the reflectance and transmittance data obtained by UV–Vis spectroscopy. The absorption coefficient was larger than 1 × 104 cm−1, and the optical bandgap was about 1.55 eV; these are suitable properties for CZTS absorption layers in CZTS thin-film solar cells.

Tailoring the thermoelectric properties of sol-gel grown CZTS/ITO thin films by controlling the secondary phases

In this work, we have demonstrated the effect of secondary phases on the thermoelectric properties of Cu2ZnSnS4 thin films (TF). The samples were grown on ITO substrate by chemical solution method and sulfurized in tube furnace having constant annealing temperature (500 °C) for different time duration (20, 40, 60 and 80 min). The temperature dependent (25–100 °C) thermoelectric properties (Seebeck coefficient, electrical conductivity and power factor) were measured using Seebeck effect and Hall effect. It was found that the value of Seebeck coefficient was increased from 70 to 753 μV/°C as the sulpurization time decreased from 80 to 20 min. The enhancement in Seebeck coefficient with decreasing sulpurized time duration is related with emergence of secondary phases which cause the filtering of slow carriers at the interface of secondary phases. The presence of secondary phases in the grown samples was confirmed by various characterization techniques. Raman spectroscopy data suggested CZTS/ITO sample sulpurized for 80 min has less secondary phase but as the sulpurized time duration decreased to 20 min, secondary phases such as Cu2S, SnS, SnS2 and ZnS were emerged and enhanced the thermoelectric properties. The XRD measurements were also verified that CZTS/ITO sample sulpurized for 20 min has poor crystal quality as compared to other samples due to the presence of secondary phases. SEM and UV/Visible spectroscopy measurements were also performed to support our argument.