Structural, morphological and optical studies of zinc selenide (ZnSe) thin films synthesized at different deposition time intervals using photo-assisted chemical bath deposition technique

ZnSe thin films were synthesized using a photo-assisted chemical bath deposition technique for different deposition time (DT) intervals from 30 to 210 min. The effects on the structure, morphology and optical properties of the films were also investigated. The thermogravimetric analysis showed that the material was thermally stable between 300 and 400 degrees C. The X-ray diffraction measurements revealed that the prepared thin films consisted of the hexagonal-wurtzite ZnSe and the crystallite sizes increased with an increase in DT. The scanning electron microscopy revealed uniform grain nanoparticles, which gradually turned to flakes as the DT was increased. The presence of the anticipated elementary compositions was detected by energy dispersive X-ray spectroscopy. UV-Visible spectrophotometry showed a red shift and both the energy band gap and transmittance were observed to decrease with an increase in DT. The photoluminescence measurements showed emission peaks at 525, 678 and 715 nm, which were all attributed to the intrinsic defects of ZnSe. Cathodoluminescence results showed emission peaks at 424, 517 and 623 nm, which are related to the near band, defect and impurity emissions in ZnSe, respectively. The luminescent analyses showed a decrease in emission intensities of the deposited samples with an increase in the DT even though there was a fluctuation in the photoluminescence.