Substrate Temperature Effect On Structural Properties Of Bi2Te3 Thin Films

Structural properties of Bi2Te3 thin films, thermally evaporated on well-cleaned glass substrate at different substrate temperature, are reported here. X-ray diffraction was carried out for the structural characterization. XRD pattern of the films exhibits preferential orientation along the [0 1 5] direction for the films of all the substrate temperature together with other supported planes [2 0 5] & [1 1 0]. All deposition conditions like thickness, deposition rate and pressure were maintained throughout the experiment. X-ray diffraction lines confirm that, the grown films are polycrystalline in nature with the hexagonal crystal structure. The effect of substrate temperature on these parameters have been investigated and reported in this paper. Various structural parameters such as lattice constants, grain size, micro strain, number of crystallites, stacking fault and dislocation density were calculated using X-ray diffraction analysis. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/939

The optimization of optical thin films deposition using in-situ reflectivity measurements and simulation

We have optimized and automated the experimental in-situ reflectivity measurement system for the laser diode (LD) facet coating. We have also developed a reflectivitysimulator program that gives the reflectivity data as a function of the thickness of the film (single or multi-layer) for a given wavelength, which aids in optimizing the above parameters while monitoring the coating of the films in-situ. We report the results for the in-situ reflectivity of a single layer MgF2 and a quarter-wave optical thick three bi-layer pairs of MgF2 and silicon on GaAs as a substrate for both the cases. We have achieved up to 83 % experimental reflectivity for the latter case. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2207

Cu2Znsns4 Thin-Films Grown By Dip-Coating: Effects Of Annealing

Recently Cu2ZnSnS4, i.e. Copper Zinc Tin Sulphide (CZTS), has emerged as a potential candidate for low-cost solar photovoltaics (PV) material because of it is relatively non-toxic and ingredient elements are earth abundant. However, achieving phase controlled, stoichiometric film of CZTS using low-cost technique is the key issue in development of CZTS based solar cell. Here, we report a study on structural and optical properties of CZTS films grown by dip-coating in view of its application as an absorber in thin film solar cells. The films were deposited by dipping glass substrates into the solution prepared by dissolving cation metal salts and thiourea in methanol. It is followed by drying the films in air at fixed temperature. The dip coated films were then annealed at 623 K, 723 K and 823 K. The influence of annealing on various structural and optical properties of the films were investigated by means of X-ray diffraction (XRD), Raman scattering spectroscopy, Scanning electron microscopy (SEM) and Diffused reflection spectroscopy. It was observed that the film annealed at 823 K shows good quality Kesterite structure of CZTS with preferred orientation of (112), (220) and (312) planes as revealed by the XRD pattern. The diffuse reflection spectra confirm the direct band-gap of 1.42 eV, which is very close to the optimum value for the semiconductor material as an absorber in solar-cells. Raman scattering with two different excitation wavelengths showed that other binary phases including the parasitic phases such as ZnS were not present. It also confirmed the characteristics signature of dominant CZTS phase in the film

Automated measurements of junction characteristics to evaluate parameters for semiconductor diodes

517-522Using National Instrument’s LabVIEW (Laboratory Virtual Instrument Engineering Workbench), a graphical programming language, we have measured the junction characteristics of different diodes in the temperature range 273-373 K. The PCI-6024E Data Acquisition Board and BNC-2120 for the acquisition of the data have been used. LabVIEW’s Controls and Functions enable one to control the experiment, measure the parameters, analyze and process the data. Ideality factor , reverse saturation current I0, and material constant B have been evaluated using I-V characteristics. The barrier height B and the band-gap energy EG, have been measured and compared using both I-V and C-V characteristics. For Schottky diode, the series resistance RS, and B can be calculated using the Norde method. The band-gap energy has been measured using constant current source. Here, we have characterized p-n junction diodes viz. 1N5402, 1N5408, 1N4148, and 6A4. In addition, LabVIEW may be used to characterize other junction diodes like zener diode, LED, varactor diode, Schottky diode, etc

Cu2ZnSnS4 thin-films grown by dip-coating: Effects of annealing

Recently Cu2ZnSnS4, i.e. Copper Zinc Tin Sulphide (CZTS), has emerged as a potential candidate for low-cost solar photovoltaics (PV) material because of it is relatively non-toxic and ingredient elements are earth abundant. However, achieving phase controlled, stoichiometric film of CZTS using low-cost technique is the key issue in development of CZTS based solar cell. Here, we report a study on structural and optical properties of CZTS films grown by dip-coating in view of its application as an absorber in thin film solar cells. The films were deposited by dipping glass substrates into the solution prepared by dissolving cation metal salts and thiourea in methanol. It is followed by drying the films in air at fixed temperature. The dip coated films were then annealed at 623 K, 723 K and 823 K. The influence of annealing on various structural and optical properties of the films were investigated by means of X-ray diffraction (XRD), Raman scattering spectroscopy, Scanning electron microscopy (SEM) and Diffused reflection spectroscopy. It was observed that the film annealed at 823 K shows good quality Kesterite structure of CZTS with preferred orientation of (112), (220) and (312) planes as revealed by the XRD pattern. The diffuse reflection spectra confirm the direct band-gap of 1.42 eV, which is very close to the optimum value for the semiconductor material as an absorber in solar-cells. Raman scattering with two different excitation wavelengths showed that other binary phases including the parasitic phases such as ZnS were not present. It also confirmed the characteristics signature of dominant CZTS phase in the film

Use of antibiotic prophylaxis in elective inguinal hernia repair in adults in London and south-east England: a cross-sectional survey.

PURPOSE: Evidence regarding whether or not antibiotic prophylaxis is beneficial in preventing post-operative surgical site infection in adult inguinal hernia repair is conflicting. A recent Cochrane review based on 17 randomised trials did not reach a conclusion on this subject. This study aimed to describe the current practice and determine whether clinical equipoise is prevalent. METHODS: Surgeons in training were recruited to administer the Survey of Hernia Antibiotic Prophylaxis usE survey to consultant-level general surgeons in London and the south-east of England on their practices and beliefs regarding antibiotic prophylaxis in adult elective inguinal hernia repair. Local prophylaxis guidelines for the participating hospital sites were also determined. RESULTS: The study was conducted at 34 different sites and received completed surveys from 229 out of a possible 245 surgeons, a 93 % response rate. Overall, a large majority of hospital guidelines (22/28) and surgeons' personal beliefs (192/229, 84 %) supported the use of single-dose pre-operative intravenous antibiotic prophylaxis in inguinal hernia repair, although there was considerable variation in the regimens in use. The most widely used regimen was intravenous co-amoxiclav (1.2 g). Less than half of surgeons were adherent to their own hospital antibiotic guidelines for this procedure, although many incorrectly believed that they were following these. CONCLUSION: In the south-east of England, there is a strong majority of surgical opinion in favour of the use of antibiotic prophylaxis in this procedure. It is therefore likely to be extremely difficult to conduct further randomised studies in the UK to support or refute the effectiveness of prophylaxis in this commonly performed procedure