## 3 Results and Discussion
At 600 nm, the transparency of Sample A-E is respectively 81.8%, 82.1%, 82.4%, 81.3%, and 80.6%. It shows that the transparency of Sample A is in the middle among five groups. The transparency of Sample B and Sample C is higher than the transparency of Sample A while the transparency of Sample D and Sample E is lower than the transparency of Sample A. Sample C and Sample E achieve the highest and the lowest transparency, respectively. When the wavelength is lower than 400 nm, the transparency of all samples declines rapidly. The optical band gap (Eg) of Zr-AZTO films can be calculated by [PERSON]'s relation [20]:  
\[(alv)^{2}=K\Big{(}hv-E_{g}\Big{)}, \tag{1}\]  
\[a=\frac{\lg\Big{(}\frac{1}{T}\Big{)}}{d}, \tag{2}\]  
where \(a\) is the absorption coefficient, \(K\) is constant, \(hv\) is the photon energy, \(T\) is the normalized transmittance, and \(d\) is the thickness of films. Figure 5 is the plot of \((alv)^{0.5}\) versus \(hv\) for Zr-AZTO films of different power combinations [21]. With the reverse extension line from the linear part of curve intersecting with the horizontal axis, the value of optical band gap can be obtained at the intersection point. As shown in Figure 5, with the discharge power of AZTO increasing from 100 W to 120 W, the value of optical band gap decreases from 2.76 eV to 2.71 eV. With the discharge power of ZrO\({}_{2}\) increasing from 15 W to 45 W, the value of optical band gap is unchanged and remains at 2.86 eV. Figure 6 shows the AFM (CSPM5500, Tapping mode) images of Zr-AZTO films of different power combinations annealed at 350 \({}^{\circ}\)C. From Figure 6, it is observed that the surfaces of all samples are flat. The RMS roughness of Sample A-E is respectively 0.446 nm, 0.402 nm, 0.387 nm, 0.399 nm, and 0.490 nm. For Sample A and Sample B, with the discharge power of AZTO target decreasing, the RMS roughness decreases as well. For Sample B-E, the RMS roughness decreases to 0.387 nm first and then increases to 0.490 nm as the discharge power of ZrO\({}_{2}\) target increases. It is found that the RMS roughness of different power combinations is approximate. Figure 4: Transmission of Zr-AZTO thin films of different groups. Figure 7 shows the crystalline of Zr-AZTO films of different power combinations annealed at 350 \({}^{\circ}\)C. There is no diffraction peak in the image after the films annealed at 350 \({}^{\circ}\)C. Thus, the Zr-AZTO films are amorphous in all conditions. This means in the film interior there is no anisotropy which can restrict the film applied on active layer. Moreover, the amorphous active layer can be used on large-scale display because of its good uniformity [22]. Figure 5: Plot of (_altv_)\({}^{0.5}\) versus _lv_ for Zr-AZTO films of different power combinations. Figure 6: The AFM images of Zr-AZTO films with different Zr content annealed at 350 \({}^{\circ}\)C: (**a**) Sample A; (**b**) Sample B; (**c**) Sample C; (**d**) Sample D; (**e**) Sample E.  
Figure 8 is the XRR images of Zr-AZTO thin films. By fitting with these curves, the physical parameters (like density, roughness and thickness) can be obtained. From Figure 8, it is found that the thin films of Sample A\(-\)E have similar curves, which indicates they have similar physical parameters. The physical parameters obtained from XRR curves are summarized in Table 3.  
Table 3 shows the physical parameters of Zr-AZTO films. Table 3 provides the density, thickness, roughness of Zr-AZTO films measured by XRR and other physical parameters mentioned in a previous part of this article. From Table 3, it is found that the Zr-AZTO films' density is around 5.90 g/cm\({}^{3}\), thickness is around 1.10 nm and thickness is around 20 nm. With the discharge power of AZTO target decreasing from 120 W to 100 W, the \(\upmu\)-PCD mean peak and D value respectively increase from 114.1 mV to 139.3 mV and from 1.24 to 1.54.