Soda-lime Glass Substrates Research Articles

Optical and electrical properties of NiO and Cu-doped NiO thin films synthesized by spray pyrolysis

Spray pyrolysis technique was employed to synthesize NiO and NiO:Cu thin films (0.1–25% Cu) on soda-lime glass substrate. Optical properties, as well as electrical resistivity of these films, were investigated. UV–Visible spectrophotometer was employed to measure the optical properties. The absorption edge of the films was located within the UV range i.e. λ = 280–380 nm. The average reflectance of the films was 16.9% in the range λ = 280–900 nm. On increasing the Cu/Ni ratio, the optical band gap decreased whereas the refractive index and Urbach energy increased. Quantitatively, the measured average value of the refractive index and the value calculated from the Reddy-Ahammed empirical formula, which connects refractive index with optical band gap, were in good agreement. Optical conductivity was found to be in the range 10 14 –10 15 s −1 while the dielectric loss was rather very low; it points to the good optical response of the films. The average oscillator energy as well as dispersion energy evaluated from Wemple–DiDomenico model decreased rapidly to begin with as Cu/Ni ratio was increased up to 5% but later on decreased rather slowly. Optical band gap values calculated by the Wemple-DiDomenico model and by Tauc relation agreed very well. The PL spectra of all the films displayed an intense peak at 403 nm and two secondary peaks at 426 nm and 365 nm. The PL intensity of each peak decreased monotonically with an increase in Cu content in NiO:Cu thin film from 0 to 3%. However, it remained almost independent of Cu content in the range of 4–25%. With an increase in Cu/Ni ratio, electrical resistivity and carrier mobility decreased whereas carrier concentration increased. • Optical band gap of NiO:Cu thin films (0–25% Cu) was in the range 3.57–3.21 eV. • Refractive index (2.15–2.42) increased on doping and average reflectance was 16.9%. • Optical band gap calculated by Tauc relation and Wemple-DiDomenico model agree well. • PL spectra of all the films displayed three peaks at 403, 426, and 365 nm. • Intensity of each PL peak decreased up to 3% Cu and then remained nearly constant.

Effect of Cu-In-Ga Target Composition on Hybrid-Sputtered Cu(In,Ga)Se2Solar Cells

High-efficiency Cu(In,Ga)Se <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (CIGSe) thin-film solar cells are typically fabricated by a multistage coevaporation process. The Cu-rich composition achieved during the second stage is known to favor the grain growth of the polycrystalline CIGSe film and has a beneficial effect on the solar cell performance. In this article, we analyze the effect of copper stoichiometry on the grain size of sputtered CIGSe absorbers and the efficiency of respective solar cells. CIGSe absorber layers were deposited on Mo-coated soda-lime glass substrates by pulsed hybrid reactive magnetron sputtering from Cu-poor and Cu-rich Cu-In-Ga targets and simultaneous Se evaporation. CIGSe films sputtered with the Cu-rich target show larger grain size and lead to better solar cell performance. Furthermore, we also introduce a two-stage process, which further increases the solar cell performance, consisting of an initial CIGSe layer deposited from the Cu-rich target followed by an indium-selenide postdeposition step. This two-stage process effectively eliminates the unwanted Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-</sub> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Se impurity phase and renders the otherwise required and toxic KCN etching unnecessary.

Effect of cesium fluoride treatment in bifacial Cu(In1-x,Gax)Se2 solar cell

Bifacial Cu(In1-x,Gax)Se2 (CIGS) thin film solar cells were fabricated on titanium-doped indium oxide (ITiO) coated soda-lime glass substrate, and the effect of cesium fluoride (CsF) treatment on solar cell performance was investigated. CsF treatment improved the photovoltaic properties of CIGS/ITiO-based solar cells not only under front-side illumination but also under rear-side illumination. The quantum efficiency for rear-side illumination improved significantly in CsF-treated CIGS solar cells. As a result, the bifaciality improved in the CsF-treated CIGS solar cell. ITiO exhibited good contact with the CIGS thin film, regardless of Cs incorporation. In addition, the effect of heat-light soaking treatment was also investigated in CIGS/ITiO-based solar cells.

Fabrication and characterization of Cd1-xZnxTe thin films for photovoltaic applications

High-quality polycrystalline Cd1-xZnxTe (0 ≤ x ≤ 1) thin films were deposited on soda-lime glass substrates by the thermal evaporation technique using a single source. The Structural, optical, and electrical properties of CZT thin films were investigated by XRD, SEM, EDX, UV/VIS/NIR spectrophotometer, Keithly source meter 2410-C and multimeter 2010. The X-ray diffraction reveals that CZT thin films are polycrystalline with predominant diffraction along the (111) plane. The Swanepoel method is used to calculate the optical constant of thin films. It was found that the refractive index increases and transmittance decreased with an increase in Zn content. The CZT thin films have a direct band-gap and ranging from 1.62 to 2.06 eV with varying Zn content. Current-Voltage measurements showed that the photocurrent of these thin films is increasing as the Zn content is increased.

Investigation of antifungal response of NiO and copper-doped NiO thin films against Aspergillus niger and Macrophomina phaseolina fungi.

Pure NiO and NiO thin films doped with 0.1 to 25% Cu were grown on pre-heated soda-lime glass substrates via spray pyrolysis technique. The surface roughness of the NiO:Cu thin films decreased as Cu/Ni ratio was increased. Antifungal activity of these thin films against Aspergillus niger (A. niger) which affects some of the fruits, and Macrophomina phaseolina (M. phaseolina) which is a soil borne fungus responsible for the infection of root and lower stem of several plants, was then investigated by bioassay and broth dilution methods. The antifungal response of pure NiO thin film was weak but it improved considerably on doping with copper. The higher the copper content in NiO:Cu thin film, the better was its antifungal response. Moreover, for the given Cu/Ni ratio range of 0-25%, the optical density (OD) of Potato Dextrose (PD) broth inoculated with A. niger and containing NiO:Cu material was reduced or antifungal ability was enhanced by 8.3, 9.9, 11.7, and 13.4 times for the exposure time of 6, 8, 10, and 12 days, respectively. Similarly, the OD of PD broth inoculated with M. phaseolina and containing NiO:Cu material was reduced or antifungal ability was enhanced by 16-37 times in the exposure temperature range of 20-40 °C. A linear relationship of OD with crystallite size and lattice strain of the thin films showed that NiO:Cu material possessed memory of the structural modifications induced by the dopant atoms though its phase changed from crystalline to non-crystalline state. These results can be utilized in agricultural sector. Graphical abstract.

Thin Films Growth of SnO_2:F/CdS/CdTe, and Studies of Their Physical and Optical Properties using Spray Pyrolysis Techniques

Fluorine doped tin oxide, Cadmium Sulphide and Cadmium Telluride thin films have been deposted on Soda Lime glass substrate at respectively by spray pyrolysis (SP) technique and are important semiconductor materials in optoelectronic devices such as optical sensors, light-emitting diodes, transistors and photovoltaic cells. thin films were characterized by various techniques such as X-ray diffraction, SEM and optical studies. X-ray diffraction measurements show that the deposited was found to be of cassiterite type with tetragonal rutile structure, observation of peaks of different planes on an X-ray diffraction graph of thin film showed that film obtained were cubic structure. The main peak value of thin film is seen at , which is the characteristic peak of the compound and the film structure was obtained at the major peak indicating the preferred orientation of films along direction. This confirms the formation of thin film, with (111) as the strongest preferred plane of orientation. The surface morphology of the thin films was analysed by scanning electron microscopy (SEM). The optical energy band gap of thin films are determine The results showed that the prepared FTO, CdS and CdTe films can be used in solar energy applications.

Elaboration of high-transparency ZnO thin films by ultrasonic spray pyrolysis with fast growth rate

In this work, ZnO films are deposited by the ultrasonic spray pyrolysis technique on soda lime glass substrates by following a specific design of experiment. The ZnO films are spray deposited using different elaboration parameters. Optical, morphological, structural and electrical properties of the ZnO films are systematically investigated. Fourier-transform infrared and transmittance spectra are measured to examine their optical properties. They are correlated to their structural properties determined by X-ray diffraction and Raman spectroscopy. The surface morphology is analyzed using atomic force microscopy while the electrical conductivity is measured using the four probe technique. This comprehensive analysis shows that ZnO thin films elaborated using ultrasonic spray pyrolysis with fast growth rate have a high transparency in a wide thickness range, making them suitable for use in applications such as all-oxide solar cells.

Optical and Electrical Analyses of Thallium Sulphide Thin Films

Abstract: In this paper, suitability of thallium sulphide films were investigated as an alternative to conventional silicon and germanium that were used as window layers in solar cells. Thin films were deposited on soda lime glass (SLG) substrates in a chemical bath containing Thallium Chloride (TlCl2) and Thiourea (NH2)2CS which was conditioned at 80 ºC for about 5 hours to deposit the films. Effects of annealing on the film samples at 300 ºC and 350 ºC were studied respectively by use of UV-VIS Avantes electrophotometer and Four-Point-Probe (FPP) machine in the light region with wavelength range from 200 nm to 1000 nm. The results obtained suggest that the thin films obtained are good materials for optoelectronics. The absorption spectra exhibited a relatively high energy band-gap. Materials of this nature are good for window layers which serve as passage to the absorber layer where needed charge carriers are produced. Keywords: Thin film, Thallium Sulphide, Window layer, Optoelectronics, Solar cells.

Multi-layer MgF2/ITO coatings for electromagnetic interference shielding

Indium tin oxide (ITO) coatings have been found useful for diverse applications including electromagnetic interference (EMI) shielding for defense and aerospace purposes, solar cells, gas sensors, etc. However, the reliability, adhesion, transmittance and control of conductivity are some issues that need to be discussed for EMI shielding. Composite multi-layer coating of magnesium di-fluoride (MgF2) and ITO have been deposited on soda lime glass substrate using electron beam (e-beam) deposition technique at a substrate temperature of 350 °C and annealed in the temperature range of 200–500 °C for 1 h under vacuum. The deposited coatings have been characterized for structural, optical and electrical properties. The deposited coatings were crystalline with a crystallite size in the range of 20–30 nm for ITO and 15–20 nm for MgF2 coatings. The coating thickness of ITO and MgF2 determined by Rutherford backscattering technique were found to be 95 nm and 12 nm, respectively. The maximum transmittance in the visible range is ~92% for as-deposited and annealed multi-layer coatings. The band gap has been found in the range of 3.95–4.02 eV, which is suitable for EMI shielding effectiveness. Raman spectroscopy confirms quantum confinement in MgF2/ITO coatings. The electrical conductivity of as-deposited MgF2/ITO coating has been found to be 200 (Ω-cm)−1 which increased to a value of 1.002 x 103 (Ω-cm)−1 for the sample annealed at 500 °C under vacuum. The multi-layer coating annealed at 500 °C show good EMI shielding effectiveness of 50.4 dB without scarifying the transmittance.

Structural analysis of sputtered amorphous silica thin films: A Raman spectroscopy investigation

In this work, a structural characterization of sputtered silica films was carried out using Raman spectroscopy. Due to the low cross-section and the thinness of the silica layer, its Raman signature is dwarfed by that of the glass substrate and is therefore difficult to extract. Overcoming these limitations represents an experimental challenge and requires the development of specific analysis strategies. For this purpose, an integrated approach for extracting and interpreting the Raman signature of amorphous silica films deposited on a soda-lime glass substrate was developed, based on three distinct methods: delamination of the sputtered silica film, addition of a reflective mask layer inserted at the silica layer-glass substrate interface, and applying a numerical signal analysis (Non-negative matrix factorization) to the multidimensional dataset acquired through depth profile acquisitions on silica films directly deposited on a glass substrate. The reliability of each proposed method is demonstrated for the extraction of the silica thin film Raman spectra. These various methods can be easily extended to other materials, either crystalline or amorphous. Furthermore, we discuss the advantages and the limits of each approach.Applying this methodology allowed us to highlight the structural differences between sputtered silica thin film and bulk vitreous silica glass (v-SiO2). Magnetron sputtering film deposition is shown to form dense silica glass layers, with an estimated densification ratio, measured by x-ray reflectivity, equal to 7%. At the medium distance range, the network connectivity change in v-SiO2 is expressed by an unusually high population of three-membered rings leading to a more compact structure. The short-range order transformation was also studied by deriving the intertetrahedral angle decrease. The present results could be a step towards advanced investigation to gain insights into the structure of films at the atomic level.

Study of Colorimetric properties of Ethidium bromide dye-doped PVP/DNA film

The effects of deoxyribonucleic acid (biological polymer DNA) on full brightness, and color matching functions of Ethidium bromide dye doped PVP/DNA films were studied. Ethidium bromide dye doped PVP/DNA films were deposited on soda-lime glass substrates by the deep casting method. The variation of CIE chromaticity coordinates for PVP/DNA films with increasing Ethidium bromide dye concentration values are determined. The CIE 1931 color space move to the magenta region. The results indicate that Ethidium bromide dye doped PVP/DNA films have potential promising material for optical device applications and candidates used for LEDs pumped by UV chips and applied in many advanced technologies.

RF-sputtered V2O5 thin films on two different glass substrates

Thin V2O5 films were deposited on two different commercial soda-lime glass substrates (A and B) by O2 reactive radio frequency magnetron sputtering using a vanadium target. The influences of the surface energy and roughness of the substrates on the structure and atomic bonding of the films were examined. The film on substrate A was polycrystalline, with eight crystal orientations, whereas the film on substrate B yielded an intense (001) diffraction peak of α-V2O5 and a weak (200) peak of β-V2O5, indicating preferred orientation along these planes. Structural analyses indicated that substrate B with lower surface energy and higher roughness enhanced the formation of a layered α-V2O5 structure.

Impact of Ar Flow Rates on Micro-Structural Properties of WS2 Thin Film by RF Magnetron Sputtering.

Tungsten disulfide (WS2) thin films were deposited on soda-lime glass (SLG) substrates using radio frequency (RF) magnetron sputtering at different Ar flow rates (3 to 7 sccm). The effect of Ar flow rates on the structural, morphology, and electrical properties of the WS2 thin films was investigated thoroughly. Structural analysis exhibited that all the as-grown films showed the highest peak at (101) plane corresponds to rhombohedral phase. The crystalline size of the film ranged from 11.2 to 35.6 nm, while dislocation density ranged from 7.8 × 1014 to 26.29 × 1015 lines/m2. All these findings indicate that as-grown WS2 films are induced with various degrees of defects, which were visible in the FESEM images. FESEM images also identified the distorted crystallographic structure for all the films except the film deposited at 5 sccm of Ar gas flow rate. EDX analysis found that all the films were having a sulfur deficit and suggested that WS2 thin film bears edge defects in its structure. Further, electrical analysis confirms that tailoring of structural defects in WS2 thin film can be possible by the varying Ar gas flow rates. All these findings articulate that Ar gas flow rate is one of the important process parameters in RF magnetron sputtering that could affect the morphology, electrical properties, and structural properties of WS2 thin film. Finally, the simulation study validates the experimental results and encourages the use of WS2 as a buffer layer of CdTe-based solar cells.

Electrical and optical properties of W-doped V2O5/FTO composite films fabricated by sol–gel method

V2O5/FTO composite films with different tungsten doping molar ratios were fabricated on soda-lime glass substrates by sol–gel spin coating method followed with annealing process. The analysis on crystallinity and surface morphology shows that W doping would induce V2O5 lattice distortion and make the film surface rougher. The resistance and transmittance during the phase transition process were measured to explore the electrical and optical properties of W-doped V2O5/FTO films. The results show that 3% W doping molar ratio is the most effective in improving the properties of V2O5/FTO films. The resistance of the prepared films is reduced by about three orders of magnitude from room temperature to 320℃. Compared to the undoped films, the 1%, 3% and 5% W-doped V2O5/FTO films possess higher conductivity and the width of the thermal hysteresis loop is narrowed from 14℃ to 13℃, 10℃ and 8℃, respectively. For undoped, 1%, 3% and 5% W-doped V2O5/FTO films, the phase transition temperature is 245℃, 238℃, 222℃ and 223℃, and the average transmittance decreased 7.7%, 7.8%, 11.7% and 5.7% in the range of 900–1400 nm before and after the phase transition, respectively.

Growth of Cu2ZnSnS4 thin films by hybrid chemical approach

Thin films of Cu2ZnSnS4 (CZTS), an emerging solar cell absorber layer, were prepared by a hybrid chemical process followed by annealing. In this process, two binary layers, SnS and ZnS were grown sequentially using chemical bath deposition method (CBD) onto soda-lime glass substrates. Subsequently the ZnS layer was partly converted into CuxS layer through an ion-exchange process by immersing the stack glass/SnS/ZnS in CuCl2 solution. The resulting stack, namely glass/SnS/ZnS/CuS, was annealed in sulphur atmosphere at 450 °C for an hour to promote inter-diffusion of the layers leading to the formation of CZTS film through the solid-state reaction path. The stack with a ZnS layer of 470 nm thick and 270 nm thick SnS led finally to the desired CZTS phase formation. XRD analysis of these films showed CZTS peaks which are close to the Cu2SnS3 (CTS) phase. Raman spectra recorded to distinguish CTS and CZTS phases showed modes at 291, 338 cm−1 corresponding to CZTS phase confirming its formation. The band gap of CZTS films is found to be 1.42 eV. The films were found to be p-type in nature. An attempt is made to fabricate heterojunction solar cell.

Improving the Cu2ZnSn(S,Se)4-Based Photovoltaic Conversion Efficiency by Back-Contact Modification

Back-contact modification using a 10-nm ZnS layer in CZTSSe-based solar cell can play a crucial role in improving photovoltaic conversion efficiency. An ultrathin layer of ZnS is deposited over Mo-coated soda lime glass substrate before depositing CZTSSe using sputtering. The crystal structure of deposited CZTSSe thin films over ZnS is recognized as (112)-oriented, polycrystalline in nature, and free from the presence of any secondary phases such as Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (S,Se) or Zn(S,Se). The bandgap of CZTSSe thin films deposited over ultrathin ZnS is observed to increase from 1.49 (deposited over Mo directly) to 1.58 eV at room temperature, as determined by spectroscopic ellipsometry. In addition, numerical simulation has been performed using SCAPS software. The impact of ZnS layer has been simulated by using the defects in the absorber and at the interface of ZnS/CZTSSe. The simulated results have been validated with experimentally fabricated CZTSSe device. Simulated device with ZnS intermediate layer is observed to give rise to a photovoltaic conversion efficiency of 15.2%.

Effect of substrate temperature on the growth of CuSbS2 thin films by chemical spray pyrolysis

CuSbS2 is an emerging potential compound semiconductor for absorber layer in thin film heterojunction solar cell. Spray pyrolysis technique has been successfully employed to deposit CuSbS2 thin films onto soda-lime glass substrates held at different substrate temperatures in the range of 220 °C–280 °C. The structural and optical analysis revealed that films deposited at 260 °C are CuSbS2 with chalcostibite structure. The films deposited at other substrate temperatures contained binary/ternary phases like Cu2-xS, Cu3SbS4 and Cu12Sb4S13. The lattice parameters of CuSbS2 films are found to be a = 0.599 nm, b = 0.379 nm and c = 1.449 nm respectively. The band gap of CuSbS2 films is close to the optimum band gap (1.5eV) required for highest theoretical photovoltaic conversion efficiency. The optical absorption coefficient value lies in the range of 104 cm−1. The nature of these films is found to be p-type.

A systematic study of how annealing conditions lead to the application-based microstructural, crystallographic, morphological, and optical features of spin-coated CdS thin-films

Abstract The thiol-amine cosolvent-assisted Triton X-100 surfactant-induced cadmium sulfide (CdS) thin-films have been spin-coated on soda-lime glass substrates at room temperature and have undergone different annealing conditions. The films obtained are annealed in open-air (OA) at a temperature of 100–300 °C and under glass-protected air (GPA) and low-vacuum at 300 °C for 5 min. Their microstructural, crystallographic, morphological, and optical properties are investigated by the XRD study, SEM study, and UV–vis spectrophotometer, respectively, whereas the dispersion parameters are obtained using the Wemple-DiDomenico model. The XRD patterns reveal that the OA- and GPA-annealed films show the coexistence of cubic and hexagonal phases, while the vacuum-annealed film only shows the hexagonal phase, indicating the phase transition of CdS film, and the GPA-annealed film has the largest crystal size. It is found that other microstructural parameters, such as dislocation density, lattice strain, and the number of crystallites per unit area depend on the annealing environment. The SEM study reveals that the surface morphology of CdS film is closely related to the annealing environment. The optical bandgap is found to be variable in the range of 2.12–2.75 eV depending on the annealing conditions. Results also show that the annealing environment extremely influences several linear and non-linear optical properties of CdS film. The experimental results indicate that changing the annealing environment can be a useful tool to obtain application-specific properties of CdS film.

Role of the Cu -Deficient Interface in Cu(In,Ga)Se2 Thin-Film Photovoltaics with Alkali-Metal Doping

$\mathrm{Cu}$-deficient phases of chalcopyrite $\mathrm{Cu}(\mathrm{In},\mathrm{Ga}){\mathrm{Se}}_{2}$ (CIGS), such as $\mathrm{Cu}(\mathrm{In},\mathrm{Ga}{)}_{3}{\mathrm{Se}}_{5}$ and $\mathrm{Cu}(\mathrm{In},\mathrm{Ga}{)}_{5}{\mathrm{Se}}_{8}$, which are occasionally referred to as ordered vacancy compounds and often unintentionally form on CIGS film surfaces and at grain boundaries, are among the most important subjects in developing chalcopyrite thin-film energy-conversion materials and devices. Here, we revisit the role of the $\mathrm{Cu}$-deficient surface layer (CDL) present at the p-CIGS/n-$\mathrm{Cd}\mathrm{S}$ interface in photovoltaic devices with the effects of alkali-metal doping. The device structure used is alkali-containing soda-lime glass or alkali-free zirconia substrate/$\mathrm{Mo}$/CIGS/${\mathrm{Cu}\mathrm{In}\mathrm{Se}}_{2}$-based CDL/$\mathrm{Cd}\mathrm{S}$/intrinsic and $\mathrm{Al}$-doped $\mathrm{Zn}\mathrm{O}$. The photovoltaic device performance deteriorates with increasing CDL thickness when no alkali metal is added. However, the CDL thickness significantly affects the results of alkali-halide $\mathrm{Rb}\mathrm{F}$ postdeposition treatment (PDT) and the use of a thick CDL enhances the beneficial effects of $\mathrm{Rb}\mathrm{F}$ PDT, resulting in photovoltaic performance enhancements manifested by improvements in the open-circuit voltage and fill-factor values. On the other hand, $\mathrm{Rb}\mathrm{F}$ PDT leads to degradation of the device performance when the CDL is thin. High $\mathrm{Rb}$ concentration and significant $\mathrm{Ga}$ diffusion from the CIGS layer to the surface CDL with $\mathrm{Rb}\mathrm{F}$ PDT are observed when the CDL is thick. The formation of metastable acceptors, namely, an increase in the nominal carrier density in CIGS, is observed with light-soaking (LS) treatments, regardless of the thickness of CDL. Nevertheless, improvements in photovoltaic efficiency with LS treatments are observed only from devices grown with a thick CDL.

Effect of magnesium content and growth temperature on structural and optical properties of USCVD-grown MgZnO films

Magnesium zinc oxide (MgxZn1-xO) films (x < 0.4) have been grown by ultrasonic spray chemical vapor deposition on soda-lime glass substrates for different growth temperature and different Mg mole fractions (x). Effects of Mg content in the liquid solution and the effect of growth temperature on optical and structural properties of MgZnO films have been investigated with X-ray diffraction, atomic force microscope, and UV–visible spectrophotometry measurements. The growth temperature has a significant effect on determining the Mg mole fractions of MgZnO films. There is a linear correlation between the measured Mg mole fraction in the resulted grown structures and Mg content in the solution. The peak of (0002) diffraction for the grown samples has been shifted to the higher diffraction angles with increase in Mg content in the liquid solution and has also become stronger. The growth temperature and Mg content in a liquid solution are crucial parameters in the controlling Mg mole fraction of samples.