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O: Fachverband Oberflächenphysik
O 82: Focus Session: Unoccupied States by Inverse Photoemission III
O 82.3: Vortrag
Donnerstag, 12. März 2026, 11:30–11:45, WILL/A317
Development of angle resolved low energy inverse photoelectron spectroscopy for conduction band structure measurements of functional materials — •yuki kashimoto1, satoshi ideta1, haruki sato1, keita kawamura1, hibiki orio1, and hiroyuki yoshida1,2 — 1chiba university, chiba, japan — 2chiba university MCRC, chiba, japan
Understanding the energy band structure is essential for clarifying charge-transport behavior in solids. Although angle-resolved inverse photoelectron spectroscopy (ARIPES) can measure conduction bands, it is unsuitable for emerging materials such as organic semiconductors due to their narrow bandwidths and electron irradiation damage. Low-energy inverse photoelectron spectroscopy (LEIPS)[1] overcame these issues by reducing the electron kinetic energy. In this study, we advanced LEIPS and enabled band-structure measurements by introducing angle-resolved detection. Stray electric and magnetic fields were suppressed, and a dedicated low angular spread, energy-scannable electron source was implemented. This enabled angle-resolved LEIPS (AR-LEIPS) with 0.23 eV energy resolution and 0.94 nm−1 momentum resolution[2]. Using AR-LEIPS, we determined the conduction band structure of pentacene, the first such measurement for an organic semiconductor[3] and revealed the conduction-band dispersion of the photovoltaic perovskite CH3NH3PbI3. [1] H.Yoshida, Chem. Phys. Lett. 539-540, 180 (2012). [2]Y.Kashimoto, H.Yoshida et al, Rev. Sci. Instrum. 94, 063903 (2023) [3] H. Sato, H. Yoshida et al, Nature Mat. 21,910 (2022).
Keywords: low-energy inverse photoelectron spectroscopy; organic semiconductor; conduction band structure