Role of film thickness on the properties of ZnO thin films grown by sol-gel method

This paper reports the effect of thickness on the structural, morphological and optical properties of zinc oxide (ZnO) films. Thickness of ZnO films varied from 98 to 366 nm with an increase in the number of deposition cycles. Surface morphological studies showed that the increase in the film thickness causes an increase in the grain size. Roughness of the films has increased from 5.8 to 47 nm with an increase in the film thickness from 98 to 366 nm. The band gap is observed to vary from 3.33 to 3.24 eV with change in the film thickness from 98 to 366 nm. Thickness of the film affected the overall properties of the ZnO films significantly. The large surface roughness makes ZnO films to be potentially used as electrode in solar cells and gas sensing applications.