Preheating-temperature effect on structural and photoluminescent properties of sol–gel derived ZnO thin films

We investigated the evolution of structural and low-temperature photoluminescence properties of sol–gel derived ZnO thin films, as a function of pre-heating temperature between 300 °C and 600 °C. The pre-heating crystallization plays an important role in the lineshape of PL spectra. The increase in pre-heating temperature enables rearrangement of atoms at the pre-heating stage, leading to c-axis oriented growth of films, modification in lineshape of impurity-defect emission, and reduction of deep-level emission intensity.