Regensburg 2016 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 90: Poster III
HL 90.15: Poster
Thursday, March 10, 2016, 16:00–19:00, Poster A
Electronic structure of lead halide perovskite — •Daniel Niesner1,2, Tyler J. S. Evans1, Bryan J. Kudisch1, Prakriti P. Joshi1, Kiyoshi Miyata1, Xiaoxi Wu1, M. Tuan Trinh1, Haiming Zhu1, Manuel Marks1, and X.-Y. Zhu1 — 1Department of Chemistry, Columbia University, New York, NY 10027, USA — 2Festkörperphysik, FAU Erlangen-Nürnberg, D-91058 Erlangen, Germany
Angle-resolved photoelectron spectroscopy (ARPES) and two-photon photoelectron spectroscopy give insight into the valence and conduction band electronic structure of semiconductors. Doping levels can directly be extracted. Experiments require samples with well-defined surfaces. We report the preparation of high-quality polycrystalline thin films of (CH3NH3)PbI3 on native silicon oxide on Si(111), sapphire, and PbSe(001). The (110) crystalline axis is orientated along the surface normal. Surface roughness is 1 nm. ARPES data are in semiquantitative agreement with band structure calculations. The valence band is located 1.5± 0.1 eV below the Fermi level EF. The films on oxide surfaces are highly to degenerately n-doped, with the conduction band minimum up to 0.08 eV below EF. Photoemission techniques are combined with optical spectroscopy taking into account the Burstein shift resulting from the high doping level. The band gap is 1.535± 0.030 eV, in good agreement with the reported value for single-crystalline (CH3NH3)PbI3.