3.3.2. Heating Rate

The process of determining the heating rate is crucial in order to acquire the optimal recombination and sensitivity [71]. Figure 9 depicts the glow curve with a different heating rate of the optimum sample. For this study, each data value identified an average of three dosimeters samples to estimate the average TL intensity and a standard deviation. The prepared samples were automatically heated at 50 ◦C by the TLD reader before recording the glow curve, and the temperature was gradually incremented at the heating rate of 1 ◦C/s up to 10 ◦C/s. Ideally, the optimum heating rate should achieve the highest TL intensity with the lowest standard deviation [72]. As shown in Figure 10, the optimum heating rate corresponding with the highest TL intensity is set at 5 ◦C/s. It was observed that the intensity of the glow curve with the different heating rates of the Ag-doped ZnO film decreased when increasing the heating rate. The glow curve is connected to trap levels in the bandgap between the conduction bands and the valence bands of material at varying depths. These trap levels are distinguished by kinetic parameters such as activation energy, live time, and frequency factor. Besides, the reduction in intensity with an increase in heating rate can be attributed to the association between the time taken to de-trap the electrons trapped and the number of electrons de-trapped due to thermal stimulation [73].

**Figure 9.** Glow curve of Ag-doped ZnO thin films as a function of heating rate.

**Figure 10.** TL response of Ag-doped ZnO thin films as a function of heating rate.
