The effect of deposition time on the structural, morphological and optical band gap of lead selenide thin films synthesized by chemical bath deposition method

• Both sodium hydroxide and ammonia are used as complexing agent to synthesize PbSe thin film.
• The deposition time strongly influenced the preferred orientations of the crystallites.
• Average crystallite sizes are increased almost linearly with deposition time.
• Structural parameters such as microstrain and dislocation density are decreased linearly with deposition time.
• The optical band gap of the film decreased from 1.25 eV to 1.11 eV as the deposition time increased from 30 min to 60 min.

Nanocrystalline lead selenide thin films have been deposited on silica glass substrates by chemical bath deposition method at a bath temperature of 90 °C and a pH of about 12. Three samples were prepared by employing different deposition times. The deposited thin films, which were uniform, well adherent and gray in color, were characterized by powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption spectroscopy. The results showed that the deposition time had a strong influence on the morphology, preferred orientation of the crystallites as well as other structural parameters such as microstrain and dislocation density. The optical band gap also varied with increasing deposition time from 1.25 eV to 1.11 eV. The elemental compositions of the films were confirmed by energy dispersive X-ray spectroscopy.