Showing 7 results for Thin Films
M. Alzamani, A. Shokuhfar, E. Eghdam, S. Mastal,
Volume 10, Issue 1 (3-2013)
Abstract
Abstract:In the present research, SiO2–TiO2 nanostructure films were successfully prepared on windshields using the sol–gel technique for photocatalytic applications. To prevent the thermal diffusion of the sodium ions from the glass to TiO2 films, the SiO2 layer was pre-coated on the glass by the sol–gel method. The substrates were dipped in the sol and withdrawn with the speed of 6cm/min-1 to make a gel coating film. The coated films were dried for 2 days at 27 °C to allow slow solvent evaporation and condensation reactions due to rapid sol–gel reaction of Titania precursor. Then, the films were annealed at 100 °C for 30min and at the final temperature (500, 700 °C) for 30 min continuously. The structure and surface morphology properties, which are as a function of annealing temperature, have been studied by SEM FE-SEM and XRD. The FE-SEM surface morphology results indicate that the particle size increases from 19 to 42 nm by increasing the annealing temperature from 500 °C to 700 °C. Likewise, XRD illustrate the crystal anatase and rutile as main phases for TiO2-SiO2 films annealed at 500 °C and 700 °C respectively. This procedure resulted in transparent, crack-free SiO2–TiO2 films.
M. Akbarzadeh, A. Shafyei, H. R. Salimijazi,
Volume 12, Issue 1 (3-2015)
Abstract
In the present study, CrN, TiN and (Ti, Cr)N coatings were deposited on D6 tool steel substrates. Physical and mechanical properties of coatings such as microstructure, thickness, phase composition, and hardness were evaluated. Phase compositions were studies by X-ray diffraction method. Mechanical properties were determined by nano-indentation technique. The friction and wear behaviour of the coatings were investigated using ball-on-disc tests under normal loads of 5, 7 and 9 N at sliding distance of 500 m, at room temperature. Scanning electron microscope equipped with energy dispersive spectroscopy, optical microscope, and 2D/3D profilometry were utilized to investigate the microstructures and wear mechanisms. Wear test results clarified that the wear resistance of (Ti, Cr)N and TiN coatings was better than that of CrN coating. The wear resistance of the (Ti, Cr)N coatings was related to the Ti content in the coatings and reduced by decreasing the Ti content. The dominant wear mechanisms were characterized to be abrasive and tribochemical wear
M. Taleblou, E. Borhani, B. Yarmand, A. Kolahi,
Volume 15, Issue 3 (9-2018)
Abstract
Thin films of SnS2 were prepared, as the absorber layer in solar cells, using an aqueous solution of SnCl4 and thiourea by spray pyrolysis technique. Effect of the Substrate temperature on the properties of these thin films was studied. Investigation via XRD showed the formation of polycrystalline SnS2 along (001) in all layers; there was no sign of other unwanted phases. With increasing of substrate temperature from 325 to 400 0C, the crystallinity of the sample was improved, after that, it deteriorated the crystallinity. Layers had granular morphology and Valley- Hills topography. UV-VIS spectra revealed that the transmittance of all layers was lower than 40% in the visible region and the band gap reduced from 2.8 to 2.55 eV with increment in temperature from 350 to 400 0C. Photoluminescence spectra of the prepared film, which was formed at 400 0C showed a dominant peak at 530 nm, caused recombination of excitons. The least electrical resistivity of the SnS2 thin film prepared at 400 0C in dark and light environment were 4.6 ×10 -3 Ωcm and 0.65×10 -3 Ωcm, respectively; which demonstrated 400 0C was the optimum temperature in point of optoelectrical properties in the SnS2 thin film.
R. Zarei Moghadam, M.h. Ehsani, H. Rezagholipour Dizaji, M.r. Sazideh,
Volume 15, Issue 3 (9-2018)
Abstract
In this work, Cadmium Telluride (CdTe) thin films were deposited on glass substrates at room temperature by vacuum evaporation technique. The deposited CdTe thin films were characterized by X-ray diffraction, UV-Visible spectroscopy and Field emission scanning electron microscope (FESEM) techniques. Structural studies revealed that the CdTe films deposited at various thicknesses are crystallized in cubic structure. The results showed the improvement of the film crystallinity upon grain size increment. Optical constants such as refractive index (n), extinction coefficient (k), real and imaginary parts of dielectric constant, volume energy loss function (VELF), and surface energy loss function (SELF) were calculated using UV-Vis spectra. In addition, band gap and Urbach energies were calculated by Tauc and ASF methods. The band gap energy of the specimens was found to decrease from 1.8 to 1.4eV with increasing the thickness of films. The absorption coefficient, computed and plotted versus the photon energy (hν) and tailing in the optical band gap, was observed which is understood based on Urbach law. Urbach energy variation from 0.125 to 0.620 eV in the samples with higher thicknesses is concluded.
Revathi Baskaran, Perumal Perumal, Deivamani Deivanayagam,
Volume 20, Issue 2 (6-2023)
Abstract
In this research, praseodymium (Pr) doped titanium oxide was deposited onto a glass substrate by nebulizer spray pyrolysis technique. The rare earth-doped thin film was subjected to studies on structural, morphological, optical, and gas sensing properties. The structural properties of the deposited thin films exhibit varied texture along with (101) direction. The grain size of the thin film varies with various mole percentages of doped TiO2 thin films. As various doping concentrations increase, the prepared thin films show different optical properties like band gap, extension coefficient, refractive index, and dielectric constant. Fourier transform infrared (FTIR) results revealed that the reflectance spectra conformed to the existence of functional groups and chemical bonding. Gas sensing studies were carried out for undoped and Pr-doped TiO2 films. The sensor was exposed to ethanol gas. The response of a TiO2 thin film at different ethanol concentrations and different operation temperatures was studied. The gas sensitivity of ethanol gas was measured when the fast response of the film with 0.004M Pr-doped TiO2 thin film showed a response time of 99 s and recovery time of 41 s, as well as the resistance falling to 0.6x106Ω. The sensor operated at maximum effectiveness at an optimum temperature of 200°C.
Sandesh Jirage, Kishor Gaikwad, Prakash Chavan, Sadashiv Kamble,
Volume 21, Issue 1 (3-2024)
Abstract
The Cu2ZnSnS4 (CZTS) thin film is newly emerging semiconductor material in thin film solar cell industry. The CZTS composed of economical, common earth abundant elements. It has advantageous properties like high absorption coefficient and best band gap. Here we have applied low cost chemical bath deposition technique for synthesis of CZTS at low temperature, acidic medium and it’s characterization. The films were characterized by different techaniques like X-Ray diffraction, Raman, SEM, Optical absorbance, electrical conductivity and PEC study. The X-Ray diffraction, Raman scattering techniques utilized for structural study. The XRD revels kasterite phase and nanocrystalline nature of CZTS thin films. These results and its purity confirmed further by advanced Raman spectroscopy with 335 cm-1 major peak. The crystallite size which was found to be 50.19 nm. The optical absorbance study carried by use of UV-Visible spectroscopy analyses its band gap near about 1.5 eV and its direct type of absorption. The electrical conductivity technique gives p-type of conductivity. The scanning electron microscopy (SEM) study finds it’s rock like unique morphology. The EDS technique confirms its elemental composition and it’s fair stoichiometry. The analysis of PEC data revealed power conversion efficiency-PCE to 0.90%.
The Cu2ZnSnS4 (CZTS) thin film is newly emerging semiconductor material in thin film solar cell industry. The CZTS composed of economical, common earth abundant elements. It has advantageous properties like high absorption coefficient and best band gap. Here we have applied low cost chemical bath deposition technique for synthesis of CZTS at low temperature, acidic medium and it’s characterization. The films were characterized by different techaniques like X-Ray diffraction, Raman, SEM, Optical absorbance, electrical conductivity and PEC study. The X-Ray diffraction, Raman scattering techniques utilized for structural study. The XRD revels kasterite phase and nanocrystalline nature of CZTS thin films. These results and its purity confirmed further by advanced Raman spectroscopy with 335 cm-1 major peak. The crystallite size which was found to be 50.19 nm. The optical absorbance study carried by use of UV-Visible spectroscopy analyses its band gap near about 1.5 eV and its direct type of absorption. The electrical conductivity technique gives p-type of conductivity. The scanning electron microscopy (SEM) study finds it’s rock like unique morphology. The EDS technique confirms its elemental composition and it’s fair stoichiometry. The analysis of PEC data revealed power conversion efficiency-PCE to 0.90%.
Rakhesh V, Sreedev P, Ananthakrishnan A,
Volume 21, Issue 2 (6-2024)
Abstract
Organic and Perovskite solar cells have attracted a lot of attention recently since they can be used with flexible substrates and have lower manufacturing costs. The configuration and materials employed in their construction, including the Electron Transport Layer (ETL), active layer, electrode contact, and hole transport layer greatly influence the stability and performance of these solar cells. This research focuses on the simulation of solar cells, specifically utilizing zinc oxide (ZnO) as the electron transport layer. A 0.1 molar ZnO thin film was prepared from Zinc acetate salt and was deposited on a glass substrate using the cost effective Successive Ionic Layer Adsorption and Reaction (SILAR) method. In-depth investigations were carried out on several factors, including structural, surface, optical and numerical analysis. The obtained parameters were utilized in the General-Purpose Photovoltaic Device Model (GPVDM) software to perform numerical simulations of the organic solar cell and Perovskite solar cell. Both Organic solar cells and Perovskite solar cells were designed numerically and through careful observations, electrical parameters like Open circuit Voltage (Voc), Short circuit current (Jsc), Fill Factor (FF), and Power Conversion Efficiency (PCE) were identified. The studies indicate the promising performance of simulated solar cells with SILAR-synthesized ZnO thin film as the ETL.
