Influence of various sol concentrations on stress/strain and properties of ZnO thin films synthesised by sol–gel technique

• Published in: Thin solid films 2013-01, Vol.527, p.102-109
• Main Authors: Malek, Mohd Firdaus, Mamat, Mohamad Hafiz, Sahdan, Mohd Zainizan, Zahidi, Musa Mohamed, Khusaimi, Zuraida, Mahmood, Mohamad Rusop
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition; Dip-coating; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Field emission; Field emission, ionization, evaporation, and desorption; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Mechanical and acoustical properties; Methods of deposition of films and coatings; film growth and epitaxy; Physical properties of thin films, nonelectronic; Physics; Sol gel process; Sol–gel; Strain; Stress; Stress concentration; Stresses; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Zinc oxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2012.11.095

ZnO thin films are deposited on glass substrates by using a sol–gel dip-coating technique with varying precursor concentrations. X-ray diffraction and field emission scanning electron microscopy analyses were used to investigate the effect of sol concentrations on the crystallinity and surface morphology of the films. The results show that with an increase in sol concentration, the value of the full-width at half-maximum of the (0 0 2) peak decreases while the strain initially decreases and then increases. Thin films deposited at high concentrations result in an increase in grain size. Studies of the optical properties of these films show that the band gap value varies between 3.266 and 3.281eV when the sol concentration changes from 0.2 to 1.0M, respectively. The 0.4M ZnO thin films exhibited lower stress/strain than other films. It was determined that the properties of ZnO thin films are influenced by the stress and strain within the films. ► The ZnO crystal orientation was influenced by strain/stress of the film. ► Highly c-axis oriented ZnO were grown at minimum strain/stress. ► Minimum stress/strain of ZnO film leads to lower defects. ► Bandgap and defects were closely intertwined with strain/stress. ► We report additional electrical and optical properties based on sol concentration.