Penning Ionization Electron Spectroscopy
Penning ionization electron spectroscopy (PIES) is based on the Penning ionization (PI) phenomenon caused by the interaction between excited metastable atoms and semiconducting or insulating surfaces (Fig. 71.1) . When the excited metastable atoms, typically excited helium atoms in the triplet state [He*(23S; 19.82 eV)], approach the material surface, the valence band electron of the materials (ΦA, ΦB, …) transfers to the 1s level of the metastable atom (χa) via tunneling. According to the energy conservation law, the energy loss of the transferred valence electron is subsequently used for the electron emission from the 2s level (χb) in the He* atoms, providing the information of spatial distribution and binding energy of the targeted atomic orbitals (AOs) or molecular orbitals (MOs).
KeywordsElectronic structure Molecular orbital distribution Molecular orientation Particle–particle interaction
- 2.Hosokai, T., Mitsuo, N., Noro, S., Nakamura, T., Kera, S., Sakamoto, K., Ueno, N.: Thickness-dependent electronic properties and molecular orientation of diradical metal complex thin films grown on SiO2. Chem. Phys. Lett. 487, 67–70 (2010)Google Scholar
- 3.Hosokai, T., Machida, H., Gerlach, A., Kera, S., Schreiber, F., Ueno, N.: Impact of structural imperfections on the energy-level alignment in organic films. Phys. Rev. B. 83, 198310(1–7) (2011)Google Scholar