Effects of sol concentration on structural, morphological and optical waveguiding properties of sol-gel ZnO nanostructured thin films

Abstract

Nanostructured ZnO thin films with different precursor concentrations (0.5-0.8 M) have been deposited on glass substrates by sol-gel dip coating technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible spectrophotometer, and m-lines spectroscopy have been employed to investigate the effect of solution concentration on structural, morphological, optical and waveguiding properties of the ZnO thin films. XRD spectra have shown that all the films are polycrystalline and exhibit the wurtzite hexagonal structure. SEM micrographs and AFM images have revealed that morphology and surface roughness of the thin films depend on sol concentration. The UV-visible transmittance results show a high transparency in the visible range and a shift of the maximum transmittance to the higher wavelength with increasing sol concentration. Waveguiding properties such as refractive index, number of propagating modes and attenuation coefficient measured at 632.8 nm wavelength by m-lines spectroscopy indicate that our ZnO slab waveguides are single mode and demonstrate optical losses estimated around 1.5 decibel per cm (dB/cm) for the thin film prepared with a sol concentration of 0.7 M.

Enhancement of multi-photon Raman scattering and photoluminescence emission from Li-doped ZnO nanowires

“…As an II-VI compound semiconductor, ZnO has been studied over the past few years due to its direct and wide band-gap (3.37 eV at room temperature) and large exciton binding energy (60 meV) [1]. These attractive properties open up a wide range of applications for ZnO materials, such as white light-emitting devices, ultraviolet laser diodes, and so on [2][3][4]. At present, there is a rapidly growing research effort with various doping elements using different methods aimed at exploring doped-ZnO nanomaterials [5,6], paralleling the domestic and international interest in pure ZnO.…”

Structural, Optical and Luminescence Properties of ZnO Thin Films Prepared by Sol-Gel Spin-Coating Method: Effect of Precursor Concentration

“…Present Exp. 0.3 3.250 3.254 [19] 5.205 5.208 [19] 0.5 3.249 3.233 [20] 5.204 5.210 [20] 0.7 3.247 3.261 [20] 5.203 5.210 [20] 0.9 3.246 5.202 1.2 3.244 5.2006 Bulk(JCPDS 75-0576) [8] 3.242 5.194 Also, the preferential orientation was characterized using the texture coefficient TC (ℎ𝑘𝑙) estimated from…”