| AVS 54th International Symposium | |
| Renewable Energy Science & Technology Topical Conference | Thursday Sessions |
| Session EN+SS+TF-ThM |
| Session: | Surface Science Challenges for Solar Energy Conversion |
| Presenter: | S.H. Cheung, Pacific Northwest National Laboratory |
| Authors: | S.H. Cheung, Pacific Northwest National Laboratory P. Nachimuthu, Pacific Northwest National Laboratory M.H. Engelhard, Pacific Northwest National Laboratory M.K. Bowman, The University of Alabama S.A. Chambers, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
N doping in TiO2 is of potential interest for bandgap reduction and enhanced visible light absorption for water splitting. We have previously investigated high-quality N-doped TiO2 rutile grown homoepitaxially by molecular beam epitaxy (MBE) on TiO2(110) and α-Al2O3(0001).1 To gain broader understanding of N-doped TiO2, we now report a detailed study of N incorporation and the associated electronic structure in high-quality TiO2 anastase grown by MBE on LaAlO3(001). A mixed beam of atomic N and O was prepared in an electron cyclotron resonance plasma source while Ti was supplied from an effusion cell. The much higher thermodynamic stability of Ti-O bonds compared to Ti-N bonds resulted in N incorporation being limited to less than 1 at. %. The high degree of structural quality was evidenced by the observation of finite thickness fringes in the vicinity of the (004) Bragg peak in high-resolution X-ray diffraction. A formal charge of -3 on substitutional N was deduced from high-resolution XPS. Photoconductivity measurement capability is being set up at the time of abstract preparation and experimental results elucidating the role of substitutional N in reducing the bandgap will be presented at the meeting.
1 S.H. Cheung, P. Nachimuthu, A.G. Joly, M.H. Engelhard, M.K. Bowman, S.A. Chambers, Surf. Sci. 601 (2007) 1754.