# Fileset [2025JJAP_Ogawa_SI.pdf](https://mdr.nims.go.jp/filesets/a7240380-5de2-477a-bf43-ff840cb57798/download) ## Creator Kenta Ogawa, [Toyohiro Chikyow](https://orcid.org/0000-0003-3860-4806), Yuki Daimon, Atsushi Ogura, [Takahiro Nagata](https://orcid.org/0000-0002-8591-2943) ## Rights This is the Accepted Manuscript version of an article accepted for publication in Japanese Journal of Applied Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://dx.doi.org/10.35848/1347-4065/add0be.[Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International](https://creativecommons.org/licenses/by-nc-nd/4.0/) ## Other metadata [Effects of interface formation process on electronic properties of n-type Ti0.3Zn0.7O1.3/p-type Si stack structure](https://mdr.nims.go.jp/datasets/d167e7fc-5c26-45c9-acf1-7cf939cc8855) ## Fulltext 1 Supplemental Information Effects of interface formation process on electronic properties of n-type Ti0.3Zn0.7O1.3/ p-type Si stack structure Kenta Ogawa1,2*, Toyohiro Chikyow2, Yuki Daimon1,2, Atsushi Ogura1,3 and Takahiro Nagata2* 1Graduate School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan 2National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan 3Meiji Renewable Energy Laboratory, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan E-mail: ce241031@meiji.ac.jp, NAGATA.Takahiro@nims.go.jp 2 [Band alignment] Figure S1 shows the band alignment of Ti0.6Zn0.4O1.6 /Si shown in the inset of Fig. 4 in the main text. The energy difference between the Fermi level (Ef) and the valence band maximum (Ev) shown in the figure were evaluated using the valence band spectra, and the band gaps were calculated using literature values1,2), respectively. As shown in this figure, the TixZn1-xO1+x /Si used in this study has the type II heterostructure, but that the unintentionally formed SiO2 layer exists at the interface. Figure S1 Band alignment of Ti0.6Zn0.4O1.4 /SiO2 /p-Si 3 [The effects of Al electrode on I-V characteristics] Figure S2 shows the (a) Al 2p, (b) Zn 2p3/2, (c) valence spectra, (d) band alignment from the aluminum electrodes on Single layer sample and (e) I-V characteristics of the Al/ Ti0.3Zn0.7O1.3 junction formed on Al2O3 substrate. From the Al 2p spectra, it didn't observe only metal Al bonding sate around 73 eV, but also Al-O bonding state was observed around 76 eV. Aluminum thickness were almost 5 nm used this measurement. At the interface, there should be an unintentionally oxidized Al2O3 layer, which should not work as insulator. Because the valence band spectra shows electronic state at the Fermi level (0 eV), and the valence band maximum shift of ZnO near 5 eV. Furthermore, the Zn 2p3/2 spectra also showed broad two peaks around 1022 and 1025 eV. These valence band and Zn 2p3/2 energy shifts suggest the possibility that the interface is metallic and the formation of ZnxAlyOz, considering the Fermi position of Ti0.3Zn0.7O1.3. These results indicate that aluminum and Ti0.3Zn0.7O1.3 form an ohmic junction, and band alignment should be as Fig. S2(d). Note, the measurement method of the band alignment except aluminum electrodes was same as Fig. S1. The evaluation of the electrical characteristics of the Al/ Ti0.3Zn0.7O1.3 junction formed on Al2O3 substrate support these results, as shown in Fig. S2(e), and shows an ohmic property. The sheet resistance was 3.6×106 Ω/□ regarding the Ti0.3Zn0.7O1.3 sample with thickness of 25 nm. Based on these results, we think that the aluminum electrode forms an ohmic junction with Ti0.3Zn0.7O1.3 and that the electrode does not affect the relative changes of the current mechanism described in the main text. 4 5 Figure S2 (a) Al 2p, (b) Zn 2p3/2, (c) Valence spectra, (d) band alignment from the aluminum electrodes on Single layer sample and (e) I-V characteristics of the Al/ Ti0.3Zn0.7O1.3 junction formed on Al2O3. 6 [Variations of area intensity of O 1s spectra of Single layer] Figure S3 shows the Zn 2p3/2, Ti 2p3/2, and O 1s spectra on three measurement points in Single layer. The spectra are labeled point_1, 2, and 3, and point_1 is the result shown in the main text. The film thickness of point_1 was 5 nm, that of point_2 was 3 nm, and that of point_3 was 2 nm. For using the same sample as the I-V measurement, we chose and described the point_1 in the main text. As shown in the figure, the area intensity of only O 1s spectra changes greatly at each measurement point, which is thought to be due to the variation in oxygen vacancies caused by the non-uniformity of Ti. Figure S3 Zn 2p3/2, Ti 2p3/2, and O 1s spectra on three measurement points in Single layer. 7 [Si 2p spectrum of ZnO first obtained by Al Kα-XPS] Figure S4 shows the Si 2p spectrum in ZnO first obtained by Al Kα-XPS. This result shows that the Zn 3p peak around 90 eV and its tail on the high binding energy side affect the Si 2p background. In addition, since Si 2p is affected by orbital splitting, when the signal at the stacking interface is weak, as shown in the figure, the difference between the three states seen in Si 1s becomes small, making the fit difficult. For these reasons, we have used Si 1s in our discussion of the interface. Fig. S4 Si 2p spectrum in ZnO first obtained by Al Kα-XPS 8 Reference 1 A. Toghan, K. K. Taha, and A. Modwi, J. Mater Sci: Mater Electron, 32, 2471 (2021). 2 K. C. L. Khang, M. H. M. Hatta, S. L. Lee, and L. Yuliati, J. Teknologi (Sciences & Engineering) 80, 153 (2018).