Effect of deposition time on structural and optical properties of ZnSe thin films grown by CBD method

Abstract

Undoped ZnSe thin films were prepared using Chemical bath deposition method (CBD). All samples were deposited on glass substrates in acidic solution at 80 °C for 60, 120, 180 and 240 min. The effect of deposition time on the structural and optical properties of ZnSe thin layers were investigated by X-Ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, atomic force microscopy (AFM), UV–Vis and photoluminescence (PL) spectroscopies. XRD patterns of the deposited thin films exhibited cubic structure with a preferred (111) orientation. The crystal quality and the average crystallite size were found to increase at higher durations of deposition. FTIR spectrum confirmed the presence of ZnSe vibration band. AFM analysis revealed that both of morphology and surface roughness were affected by time of deposition. According to UV–Vis results, all samples were transparent with average visible transmission values ranging from 55% to 72%. The optical band gap was found to decrease with increasing deposition time. The room temperature PL spectra indicated the presence of three emissions at 460, 575 and 630 nm.