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

► 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.