Heating rate of post-annealing on microstructure/electrical/optical properties of gallium and aluminum co-doped zinc oxide films

To investigate whether heating rate of post-annealing can affect the microstructure, electrical and optical properties of gallium and aluminum co-doped zinc oxide (GAZO) films or not, GAZO films were post-annealed with 9°C/min and 30°C/min heating rate. The GAZO films post-annealed with 9°C/min heating rate appears smaller full width at half maxima of (002) diffraction peak, more uniform and bigger grain size, higher mobility, lower resistivity, higher average optical transmittance and higher figure of merit than those with 30°C/min heating rate. Low heating rate like 9°C/min in post-annealing can provide more time in thermal reaction for GAZO films at a certain heating temperature. This scenario may explain the above phenomena.