## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Device**} & \multirow{2}{*}{
\begin{tabular}{c} **Stress** \\ **Time (s)** \\ \end{tabular} } & \multicolumn{6}{c}{**Negative Bias Stress (NBS)**} & \multicolumn{6}{c}{**Positive Bias Stress (PBS)**} \\ \cline{3-10}  & & \(\mathbf{H_{\text{sat}}}\) **(cm\({}^{2}\)** & \(\mathbf{I_{\text{on}}}\)/\(\mathbf{I_{\text{off}}}\) & **SS (V/dec)** & \(\mathbf{V_{\text{th}}}\) **(V)** & \(\mathbf{I_{\text{on}}}\)/\(\mathbf{I_{\text{off}}}\) **(\(\mathbf{\times}\) 10\({}^{5}\))** & **SS (V/dec)** & \(\mathbf{V_{\text{th}}}\) **(V)** \\ \hline \multirow{6}{*}{Device A} & 0 & 12.7 \(\pm\) 0.34 & 7.6 \(\pm\) 0.51 & 0.34 \(\pm\) 0.06 & 3.34 \(\pm\) 0.05 & 11.9 \(\pm\) 0.32 & 5.6 \(\pm\) 0.42 & 0.37 \(\pm\) 0.05 & 3.81 \(\pm\) 0.07 \\  & 900 & 12.4 \(\pm\) 0.35 & 7.6 \(\pm\) 0.55 & 0.35 \(\pm\) 0.07 & 3.55 \(\pm\) 0.08 & 8.5 \(\pm\) 0.21 & 2.6 \(\pm\) 0.22 & 0.45 \(\pm\) 0.05 & 4.28 \(\pm\) 0.06 \\ \cline{1-1}  & 1800 & 12.3 \(\pm\) 0.30 & 7.5 \(\pm\) 0.55 & 0.34 \(\pm\) 0.04 & 3.63 \(\pm\) 0.06 & 7.7 \(\pm\) 0.20 & 2.2 \(\pm\) 0.19 & 0.46 \(\pm\) 0.04 & 4.40 \(\pm\) 0.04 \\ \cline{1-1}  & 2700 & 12.2 \(\pm\) 0.31 & 7.0 \(\pm\) 0.52 & 0.35 \(\pm\) 0.05 & 3.70 \(\pm\) 0.04 & 7.5 \(\pm\) 0.20 & 2.2 \(\pm\) 0.19 & 0.47 \(\pm\) 0.02 & 4.40 \(\pm\) 0.02 \\ \cline{1-1}  & 3600 & 12.1 \(\pm\) 0.31 & 6.8 \(\pm\) 0.50 & 0.35 \(\pm\) 0.06 & 3.67 \(\pm\) 0.05 & 7.4 \(\pm\) 0.20 & 2.1 \(\pm\) 0.18 & 0.48 \(\pm\) 0.02 & 4.43 \(\pm\) 0.02 \\ \hline \multirow{6}{*}{Device B} & 0 & 9.8 \(\pm\) 0.10 & 0.92 \(\pm\) 0.058 & 0.55 \(\pm\) 0.06 & 3.49 \(\pm\) 0.16 & 9.5 \(\pm\) 0.28 & 0.090 \(\pm\) 0.0062 & 0.70 \(\pm\) 0.05 & 3.62 \(\pm\) 0.03 \\ \cline{1-1}  & 900 & 9.7 \(\pm\) 0.02 & 1.5 \(\pm\) 0.098 & 0.49 \(\pm\) 0.03 & 3.52 \(\pm\) 0.06 & 8.6 \(\pm\) 0.42 & 0.067 \(\pm\) 0.0051 & 0.74 \(\pm\) 0.02 & 5.10 \(\pm\) 0.06 \\ \cline{1-1}  & 1800 & 9.9 \(\pm\) 0.02 & 1.3 \(\pm\) 0.084 & 0.51 \(\pm\) 0.04 & 3.42 \(\pm\) 0.03 & 8.5 \(\pm\) 0.37 & 0.13 \(\pm\) 0.0098 & 0.70 \(\pm\) 0.03 & 4.96 \(\pm\) 0.01 \\ \cline{1-1}  & 2700 & 9.9 \(\pm\) 0.96 & 1.8 \(\pm\) 0.15 & 0.44 \(\pm\) 0.14 & 3.27 \(\pm\) 0.04 & 7.8 \(\pm\) 0.41 & 0.12 \(\pm\) 0.0098 & 0.69 \(\pm\) 0.03 & 5.11 \(\pm\) 0.03 \\ \cline{1-1}  & 3600 & 9.5 \(\pm\) 0.48 & 0.58 \(\pm\) 0.056 & 0.58 \(\pm\) 0.04 & 3.17 \(\pm\) 0.05 & 7.1 \(\pm\) 0.04 & 0.13 \(\pm\) 0.011 & 0.69 \(\pm\) 0.03 & 5.18 \(\pm\) 0.03 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Electrical characteristics of the devices. Device A: The TFTs with the ZrO\({}_{2}\) films obtained by spin-coating with 0.3 M precursor for 6 times. Device B: The TFTs with the ZrO\({}_{2}\) films obtained by spin-coating with 0.6 M precursor for 3 times. Figure 6: Bias stability of the TFT with ZrO\({}_{2}\) film fabricated by 0.6 M precursor spin-coating 3 times. **(a)** Output curves and gate capacitance as a function of voltage. **(b)** Transfer curves with gate-leakage current curves of positive bias stress. **(c)** Plots of sqrt Id\({}_{\text{ds}}\) (drain/source current) versus gate overdrive of positive bias stress. **(d)** Output curves and gate capacitance as a function of voltage. **(e)** Transfer curves with gate-leakage current curves of negative bias stress. **(f)** Plots of sqrt Id\({}_{\text{ds}}\) (drain/source current) versus gate overdrive of negative bias stress. Figure 8: The trend of electrical characteristics of the TFT with ZrO\({}_{2}\) film fabricated by 0.6 M precursor spin-coating 3 times. (**a**) Positive bias stress. (**b**) Negative bias stress. Figure 7: The trend of electrical characteristics of the TFT with ZrO\({}_{2}\) film fabricated by 0.3 M precursor spin-coating 6 times. (**a**) Positive bias stress. (**b**) Negative bias stress. The leakage current densities (shown in Figure 3) of ZrO\({}_{2}\) films obtained by spin-coating with 0.6 M and 0.3 M precursor for three and six times, respectively, were quite similar. However, the bias stability of the TFTs based on them were greatly different.