X-ray diffraction line profile analysis of nanocrystalline PbSe thin film prepared at different pH value by chemical bath deposition technique

Abstract

Delicate films of nanocrystalline PbSe are made at pH values of 10.5, 11, 11.5 and 12 by using the chemical bath deposition technique at constant concentration and deposition temperature. X-ray diffraction studies confirmed that the deposited PbSe thin films on the glass substrates are polycrystalline in nature with a cubic pattern. The different structural parameters, like crystallite size, shape, lattice constant, micro-strain and dislocation density, are determined from the X-ray diffraction peaks. The calculated lattice constants deviate from the bulk values, and their corrected lattice constant values are obtained from the Nelson-Riley plots. The average particle sizes obtained by using Scherrer’s formula are found in the range of 13.6 nm - 23.4 nm, which are correlated with the crystallite sizes obtained from different modified Scherrer’s methods. Crystallite size increases with an elevation in pH value, while dislocation density decreases from 5.4 × 10¹⁵ lines/nm² to 2.1 × 10¹⁵ lines/nm². Based on the Williamson Hall technique, lattice strain is found to vary between 6.06 × 10⁻³ and 5.21 × 10⁻³. The stress determined by the uniform stress deformation model is found to be 3.8134 × 10⁸ Pa, 2.3496 × 10⁸ Pa, 2.1084 × 10⁸ Pa and 1.6411 × 10⁸ Pa for pH values 10.5, 11, 11.5 and 12 respectively. Also, the energy density decreased from 1.5229 × 10⁶ kJm⁻³ to 0.8619 × 10⁶ kJm⁻³ with increased in pH value as obtained by uniform deformation energy density model. The Scanning electron microscope photographs demonstrate that prepared films are firmly in contact with the glass substrates without any voids and consist of particles with different shapes and sizes in between 45.2 and 66.4 nm. The elemental composition analysis is carried out by Energy dispersive analysis X-ray and confirmed the presence of Pb and Se in prepared films.