Status : Verified
| Personal Name | Martinez, Melanie M. |
|---|---|
| Resource Title | Fabrication of Tin Oxide/Nitrogen-doped Titanium dioxide Heterojunction thin films |
| Date Issued | 06 July 2023 |
| Abstract | Titanium dioxide (TiO2) is an n-type semiconductor that is commonly used as an optoelectronic material due to its high stability. These applications include as photocatalysts and as photovoltaic devices. However, TiO2 has poor absorption in the visible-light region. Hence, to improve its visible light sensitivity, TiO2 can be doped with nitrogen (N). Doping TiO2 with N also exhibits p-type conductivity. Tin oxide (SnO2) is an n-type semiconductor that is also used as an optoelectronic material. Coupled together, the two can form a heterojunction. In this study, 120-nm thick SnO2 films are deposited on 250-nm thick N-doped TiO2 films grown on silicon dioxide substrates. N-doped TiO2 is produced by reactive sputter deposition of titanium nitride (TiN) films with post-deposition annealing. Grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy confirmed the formation of N-doped TiO2 when TiN is annealed at 450◦C. Interstitial doping was considered to be the major doping mechanism. UV-vis spectral analysis showed an increase in absorbance in the visible light region with a shift in the optical band gap from 3.33 eV for TiN to 2.51 eV for N-doped TiO2. Hall effect measurements revealed TiN and N-doped TiO2 film resistivities on the order of 10−4 Ω-cm. Carrier densities are on the order of 1021 cm−3. Carrier mobilities up to around 45 cm2 V−1 s−1. Sheet resistances below 6 Ω sq−1. For annealed SnO2 film, resistivity was around 0.091 Ω-cm, electron carrier density of around 1019 cm−3, carrier mobility around 2 cm2 V−1 s−1, and sheet resistance around 8000 Ω sq−1. The current-voltage characteristic of the SnO2-N-doped TiO2 heterojunction thin films exhibited a rectifying behavior under dark and light illumination. |
| Degree Course | Master of Science in Materials Science and Engineering |
| Language | English |
| Keyword | thin film deposition, plasma, magnetron sputtering, photovoltaic devices |
| Material Type | Thesis/Dissertation |
Preliminary Pages
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Category : F - Regular work, i.e., it has no patentable invention or creation, the author does not wish for personal publication, there is no confidential information.
Access Permission : Open Access