## 3 Results  
Figure 1a,b show the GIAXRD spectra of samples A, B, and C, and the magnified picture of the (311) diffraction line in the MgIn\({}_{2}\)O\({}_{4}\) phase. Samples A and B demonstrate significant amorphous phases and inconspicuous peaks located at 20 = 32.5\({}^{\circ}\), which correspond to the spinel MgIn\({}_{2}\)O\({}_{4}\) (311) phase [16]. Clear diffraction peaks in Sample C indicate its polycrystalline structure and its signal may be attributed to the In\({}_{2}\)O\({}_{3}\) cubic structure (JCPDS Card No. 76-0152), which corresponds to \(<\)221\(>\), \(<\)222\(>\), \(<\)400\(>\), \(<\)441\(>\), \(<\)440\(>\), \(<\)611\(>\), and \(<\)622\(>\); the In\({}_{2}\)O\({}_{3}\) cubic structure (JCPDS Card No. 06-0416), which corresponds to \(<\)521\(>\); and the MgIn\({}_{2}\)O\({}_{4}\) spinel structure (JCPDS Card No 40-1402) which corresponds to \(<\)541\(>\). Transfer characteristic curves of MgInO TFTs were measured under V\({}_{\rm DS}\) = 10 V and a range of V\({}_{\rm GS}\) = -30 to 20 V, as shown in Figure 2. Table 1 presents the electric performance of three samples, including threshold voltage, field effect mobility, subthreshold swing, and on/off ratio. Carrier mobility can be calculated as follows [17]:  
\[I_{DS}=\frac{\rm W}{2L}C_{il}\mu_{sat}(V_{GS}-V_{TH})^{2} \tag{1}\]  
where W and \(L\) are the width and length of the channel, respectively; \(Ci\) is the capacitance of the dielectric layer per unit area; \(\mu_{sat}\) is the field effect mobility; and \(V_{th}\) is the threshold voltage. Mobility increased from 0.134 to 2.01 cm\({}^{2}\)/V-s when In\({}_{2}\)O\({}_{3}\) content increased. The threshold voltage shifted in the negative direction, likely due to the increase in number of oxygen vacancies as the donor in the MgInO material system. In addition, the threshold voltage is defined from the linear extrapolation of \(I_{DS}\)1/2 versus \(V_{GS}\). The intersection of the linear extrapolation and the \(x\)-axis is the V\({}_{\rm TH}\) value. S.S is the change in gate voltage needed to increase the drain current by one order of magnitude with respect to the switching speed of the device, and can be expressed as follows:  
\[\rm S.S=\frac{\partial V_{GS}}{\partial(logI_{DS})} \tag{2}\]  
S.S decreased from 2.59 to 1.81 V/decade and then increased to 2.83 V/decade, likely due to grain boundaries and other defects that act as carriers for scattering and trapping sites. Thus, gate controllability deteriorated and the gate insulator would likely be damaged because of the large sputter power of sample C. Moreover, the on/off ratio of samples was at approximately 10\({}^{5}\). However, when raising the In\({}_{2}\)O\({}_{3}\) power from 70 W, however, greater In\({}_{2}\)O\({}_{3}\) leads to high conductivity performance with no transfer characteristic. It is also worth noting that each measurement was repeated three times; the deviation value was less than 1% and there were differences between the three groups on the same variable. Figure 1: **(a)** Glancing incidence angle X-ray diffractometry (GIAXRD) spectra of three samples. **(b)** The magnified picture of the (311) diffraction line of the MgIn\({}_{2}\)O\({}_{4}\) phase. Figure 3 shows the output characteristic curves under different gate voltages from 0 to 10 V. The increasing drain current and off-current of the device as gate voltages increase demonstrate the operational modes of n-channel TFTs. The conductivity of the channel layer increased due to the increase in sputtering power of indium oxide. The high sputtering power of indium oxide increases the carrier concentration in the thin film. Figure 4 showed XPS and fitting spectra of O 1s deconvolution with Gaussian function confirms the concentration of oxygen vacancy in the thin film, the detail values were summarized in Table 2. The three peaks, M-O, Vo, and M-OH, can be attributed to O\({}_{2}\)\({}^{-}\) ions in metal oxide lattices, oxygen vacancies, and M-OH compounds on the surface, respectively [18].