S.L. Patel

Bio: S.L. Patel is an academic researcher from Mohanlal Sukhadia University. The author has contributed to research in topics: Thin film & Annealing (metallurgy). The author has an hindex of 12, co-authored 37 publications receiving 323 citations.

Thermal annealing evolution to physical properties of ZnS thin films as buffer layer for solar cell applications

Abstract: The conventional CdS window layer in solar cells is found to be hazardous for the environment due to toxic nature of the cadmium . Therefore, in order to seek an alternative, a study on effect of post-annealing treatment on physical properties of e-beam evaporated ZnS thin films has been carried out where films of thickness 150 nm were deposited on glass and indium tin oxide (ITO) substrates. The post annealing treatment was performed in air atmosphere within the temperature range from 100 °C to 500 °C. X-ray diffraction analysis reveals that the films on glass substrate are found to be amorphous at low temperature annealing (≤300 °C) while have α -ZnS hexagonal phase (wurtzite structure) at higher annealing. The patterns also show that the possibility of oxidation is increased significantly at temperature 500 °C which leads to decrease in direct band gap from 3.28 eV to 3.18 eV except films annealed at 300 °C (i.e. 3.39 eV). The maximum transmittance is found about 95% as a result of Doppler blue shift while electrical analysis indicated almost ohmic behavior between current and voltage and surface roughness is increased with post-annealing treatment.

Pathophysiology of pulmonary complications of acute pancreatitis

Abstract: Acute pancreatitis in its severe form is complicated by multiple organ system dysfunction, most importantly by pulmonary complications which include hypoxia, acute respiratory distress syndrome, atelectasis, and pleural effusion. The pathogenesis of some of the above complications is attributed to the production of noxious cytokines. Clinically significant is the early onset of pleural effusion, which heralds a poor outcome of acute pancreatitis. The role of circulating trypsin, phospholipase A2, platelet activating factor, release of free fatty acids, chemoattractants such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6, IL-8, fMet-leu-phe (a bacterial wall product), nitric oxide, substance P, and macrophage inhibitor factor is currently studied. The hope is that future management of acute pancreatitis with a better understanding of the pathogenesis of lung injury will be directed against the production of noxious cytokines.

The effect of post annealing temperature on grain size of indium-tin-oxide for optical and electrical properties improvement

Abstract: Background (Problem) Indium tin oxide (ITO) is a transparent conductive oxide (TCO) thin film used as a transparent electrode. Given its high demand for the manufacture of transparent electrodes (high visible light transmittance, low resistance) in applications such as liquid crystal displays, touch screens, light emitting devices and solar cells, ITO thin films have attracted immense research interest. Objectives This study determines the effect of grain size on the optical and electrical properties of the ITO thin films under different annealing temperatures. Materials and methods ITO thin film was deposited at room temperature by a high frequency magnetron sputtering method using a target composed of In2O3 and SnO2. The structural, optical and electrical properties of the thin films annealed at 250 °C, 350 °C, 450 °C and 550 °C for 1 h were then analyzed. Results The research shows the grain size of indium-tin oxide thin films is strongly related to annealing conditions. The grain size was found to increase with increasing annealing temperature, although the crystal structure did not change for all the samples. It was observed that the lowest resistivity (500 × 10−4 Ω-cm) and highest optical transmittances (90–98%) of ITO films were obtained at annealing temperature of 450 °C. At low annealing temperatures, the measured resistivity is dependent on the effect of grain size, where it decreases with increasing grain size. Conclusion This work showed that the grain size of ITO thin films is strongly influenced by post annealing technique and conditions applied, thus providing a tool for enhancing the optical and electrical properties of the film.

WS2: A New Window Layer Material for Solar Cell Application.

Abstract: Radio frequency (RF) magnetron sputtering was used to deposit tungsten disulfide (WS2) thin films on top of soda lime glass substrates. The deposition power of RF magnetron sputtering varied at 50, 100, 150, 200, and 250 W to investigate the impact on film characteristics and determine the optimized conditions for suitable application in thin-film solar cells. Morphological, structural, and opto-electronic properties of as-grown films were investigated and analyzed for different deposition powers. All the WS2 films exhibited granular morphology and consisted of a rhombohedral phase with a strong preferential orientation toward the (101) crystal plane. Polycrystalline ultra-thin WS2 films with bandgap of 2.2 eV, carrier concentration of 1.01 × 1019 cm−3, and resistivity of 0.135 Ω-cm were successfully achieved at RF deposition power of 200 W. The optimized WS2 thin film was successfully incorporated as a window layer for the first time in CdTe/WS2 solar cell. Initial investigations revealed that the newly incorporated WS2 window layer in CdTe solar cell demonstrated photovoltaic conversion efficiency of 1.2% with Voc of 379 mV, Jsc of 11.5 mA/cm2, and FF of 27.1%. This study paves the way for WS2 thin film as a potential window layer to be used in thin-film solar cells.