Fabrication and Characterization of Highly Textured Thin Films of Undoped and Ag-Doped ZnO

Abstract

Undoped and Ag-doped ZnO thin films with different silver concentrations (0, 1, 3, and 7 wt%) were synthesized by sol-gel method and deposited onto glass substrate by dip-coating technique. Zinc acetate dehydrate and silver nitrate were used as starting materials. 2-Methoxyethanol and ethanolamine were used as solvent and stabilizer. Characterization by X-ray diffraction has revealed that the undoped and Ag-doped ZnO are polycrystalline, and have the wurtzite hexagonal structure with a preferred orientation along c-axis. The nanometric size (27-34 nm) of ZnO crystallites varies with the concentration of Ag. The surface morphology analysis, by atomic force microscopy and scanning electron microscopy, depicts a homogeneous dispersion of ZnO crystallites in the form of randomly spread wrinkles-like formation. The Raman spectroscopy confirms the Ag incorporation in the ZnO lattice. All films exhibit a transmittance greater than 75% in the visible region, and a sharp absorption band at 325 nm corresponding to the fundamental absorption edge. The room-temperature photoluminescence spectra of the prepared thin films display a strong ultraviolet band at 380 nm originated from excitons recombination, and four bands in the visible region at 430 nm (violet), 460 nm, 480 nm (blue) and 530 nm (green) from created defect levels in the band gap. These synthesized materials may be potential candidates in the manufacture of devices using short wavelengths.

Colloidal synthesis and characterization of nanostructured pure ZnO and In doped ZnO thin films

“…3 in the range from 50 to 1500cm − 1 . The frequencies of the phonon modes detected for these lms are assembled in Table 3, and are in agreement with those reported in various works [17,21].…”

“…Usually, the Raman peaks observed between 560 and 595cm − 1 are considered to be associated with intrinsic lattice defects and often arise from doping [22], such as oxygen vacancies, interstitial Zn and their combinations, or from regions where oxygen is de cient [21].…”

“…[13] and Herzi and al. [21], for ZnO thin lms prepared by colloidal and sol-gel methods, respectively.…”

Characteristics of ZnO and Al Doped ZnO Thin Films Prepared by Sol Gel Method for Solar Cell Applications

“…The highest optical band gap, 3.26 eV, was achieved in the ZnO thin lms doped with 3% Al [49]. The estimated optical band gaps are identical to those reported by several authors; this enables undoped and doped ZnO thin lms to be a transparent material and justi es their use as front windows in optoelectronic devices [49,50,55].…”

Room temperature ferromagnetism and dielectric enhancement in nanocomposites ZnO doped with iron

“…At 100 and 566 cm -1 the hexagonal ZnO basic phonon modes were found, which correspond to the E 2 low and A 1 (LO)/E 1 (LO) phonon modes, respectively. 2E 2 low is responsible for the 197 cm -1 peak, which may be according to charge carrier concentration [43][44][45]. The Raman peak at 325 cm -1 in prepared samples spectra attributed to zone boundary phonons (3E 2 high -E 2 low ) and peak at 439 cm -1 (E 2 high ), recorded the wurtzite hexagonal phase in all samples due to the C 4 6v space group.…”