Crystal size determination by comparative methods by X-ray Diffraction in nanocrystalline thin film of Clausthalite and its effect on its photovoltaic properties for applications in solar cells

In the deposition chemical bath synthesis method, the preparation parameters have an important role that determines the final nature of the product formed. There are several factors that affect the structural properties.The variation of the temperature was between 40-60ºC and the range of the time used was between 60 to 240 minutes.The crystal size was estimated by X-ray diffraction. It has been observed that the temperature during the chemical bath deposition is decisive in the optimal morphology properties of the thin film.The crystal size increases as a function of the temperature within an range size of 20 to 30 nm. The band gap does not change significantly with values of 1.06 to 1.1 eV as temperature function.The I-V measurement under dark and bright conditions indicate very low resistance for nanofilms with the optimum temperature (60ºC), optimum time (180-195 min) and thickness values (210-225 nm). The exceptional behavior in the conductivity of (7–11) x10^-3W^-1cm^-1 , makes this material an ideal material for the constructions of a solar cells devices.

Different methods widely used in X-ray diffraction crystal size estimation are compared and these are based on the method of Scherrer, Monshi-Scherrer, Halder-Wagner, Williamson-Hall and Whole Powder Pattern Fitting of PDXL Software Rigaku. FE-SEM (Field Emission Scanning Electron Microscopy) analysis was used as a method of comparison of the results obtained by the different methods applied from the accuracy parameter.The Monchi-Scherrer method is easy to use and the error decreases by applying the linear adjustment by least squares. The trend line intercept provides a more accurate crystal size value. The Halder-Wagner Method is constructed assuming a broadening of the diffraction peak is Voight's symmetric function and the adjustment of the trend line by least squares generates high dispersion in the points and the slope of the line provides a value of less accurate as size crystal. The Williamson-Hall Method considers peak broadering as a function of the diffraction angle that is expected to be the result of the combination of broadening and strain broadening and the adjustment of the line by least squares gives a value of crystal size from the slope quite far from FE-SEM. In conclusion, it is obtained that it is the Monshi-Scherrer method is the most accurate method.