Cadmium sulphide (CdS) is the n-type, wide band gap II-VI semiconducting material by offering applications in photovoltaics. Among the range of applications offered by CdS thin films, it has found application as a window layer in second generation solar cells by creating photon traps, thereby quantum efficiency. Closed space sublimation (CSS) offers a trivial yet effective approach for the synthesis of thin films for solar cell applications at moderate temperatures. CdS thin films of controlled thicknesses were synthesized by CSS technique by varying exposure time. X-rays diffraction data of these thin films revealed polycrystalline nature with a preferred orientation along (002) direction. The scanning electron microscopy (SEM) based morphological studies showed grain size variation with an increase in thickness of deposited thin films in the range of 300-500 nm. The electrical studies revealed high resistivity of the order of 10 6 Ω-cm. Spectrophotometric studies performed for CdS thin films concluded with the calculation of the optical parameters such as refractive index, absorption coefficient employing the Swanepoel model, and energy band gap of ~2.42 eV using the Tauc relation in addition to thin film thickness confirmation. The variations in thickness affect the structure, surface, optical 1 , electrical properties.
Cds and CdTe both are effective absorber semiconductors for thin-film solar cells. It is a naturally n-type material, which has a direct bandgap value of 2.42 eV at room temperature It has great importance in light detectors in this work, CdS thin films (TF) were synthesized on glass substrates by RF Magnetron sputtering technique in an inert gas atmosphere. The electrical properties of CdS were characterized by the Van Der Pauw method. The films showed p-type conductivity, while the films deposited at different annealed times exhibited n-type conductivity. The resistivity of the CdTe films decrease as the conductivity increased. As the source rate was increased, the hole concentration in the as-grown p-type CdTe films increased. It was also reported annealing process affects the electrical properties. Al doping CdS the value of resistivity becomes minimum as the resistivity becomes maximum although mobility has maximum value after an increase in Al doping the mobility value. As a result, the CdS/CdTe thin-film showed enhanced electrical properties for solar cell applications.
Aims
Antibiotic resistance is a major problem in Salmonella enterica serovar Typhi. The objective of this study was to evaluate the prevalence of XDR Salmonella among local population of Lahore and genotyping of isolates for antibiotic‐resistant genes.
Methods and Results
A total of 200 blood samples from suspected typhoid fever patients were collected. One hundred and fifty‐seven bacterial samples were confirmed as Salmonella Typhi and 23 samples were confirmed as Salmonella Paratyphi after biochemical, serological and PCR based molecular characterization. Antibiogram analysis classified 121 (67·2%) Salmonella isolates as MDR and 62 isolates (34·4%) as XDR. The predominant resistance gene was ampC with 47·7% prevalence, followed by gyrA, catA1, tet(A), aac (3)‐la, qnrS, blaNDM‐1 and blaCTX‐M‐15 genes in 45·5, 40, 21·6, 18·3, 11·6, 2·2 and 0·5% isolates respectively. Sequence analysis showed the presence of sul1 and dfrA7 gene cassette arrays in 12 class 1 integron integrase positive isolates.
Conclusion
Large number of clinical XDR S. Typhi‐resistant against third generation cephalosporins have been reported.
Significance and Impact of the Study
The current study highlights the possible emergence of clinical XDR S. Typhi cases in Lahore, Pakistan. Potential attribution of phenotypic and genotypic XDR cases may help to contribute targeted therapy.
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