Effect of hydrazine hydrate as complexing agent in the synthesis of zinc selenide thin films by chemical bath deposition

ZnSe thin films were deposited using hydrazine hydrate (HH) as the only complexing agent. The deposition was carried out on glass substrates in an alkaline medium at low temperature using the chemical bath deposition method. The films were annealed at 300 °C for 2 h. The effects of varying the HH volumes on the structural and optical properties of the films were investigated. The investigations were based on glancing incidence X-ray diffraction, Raman spectroscopy, Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS), UV-Visible spectrophotometry, and photoluminescence (PL) spectroscopy. The results revealed that the ZnSe films were of the wurzite structure. Raman spectra showed longitudinal optical vibrational peaks with intense peak at around 251 cm⁻¹. There were fluctuations in the Raman peaks intensities. However, the intensity of the 20 mL HH sample emerged the highest. The morphology of the thin films changed from spherical grains to nanoflakes as the HH volume was increased from 5 to 35 mL, respectively. EDS of the films confirmed the presence of Zn and Se. The bandgaps of the films decreased with an increase in the HH volume. PL measurements indicated two emission peaks at 530 and 678 nm when excited at 325 nm. These emission peaks are attributed to the intrinsic intra-bandgap defects. The intensities of the peaks increased with an increase in the HH volume. The commission Internationale de l'Elcairage color coordinates confirmed that the deposited ZnSe films exhibited green-red emission and the emission color was influenced by varying the HH volumes.