Resonant effects on two-photon photoemission spectroscopy: Linewidths and intensities of occupied and unoccupied features for lead phthalocyanine films on graphite

Two-State Double-Continuum Fano Resonance at the Si(100) Surface

“…On a more general ground, we note that as long as lifetimes and dephasing times are comparable, light absorption will be modified by the coupling between discrete states and bulk continua. This situation is already found in a variety of systems [14][15][16]. All these publications show unexpected intensity variations in the 2PPE process, which our model should be able to describe.…”

“…For the Si(100) surface the two-photon photoemission (2PPE) intensity exhibits complex interference phenomena as a function of the excitation energy, which can be explained by a two-state double-continuum extension of Fano's theory. Our observations and modeling are general and clarify unexplained intensity variations in optical absorption, for example, at surfaces [14], in nanostructures [15], and organic thin films on inorganic substrates [16].…”

“…For the Si(100) surface the two-photon photoemission (2PPE) intensity exhibits complex interference phenomena as a function of the excitation energy, which can be explained by a two-state double-continuum extension of Fano's theory. Our observations and modeling are general and clarify unexplained intensity variations in optical absorption, for example, at surfaces [14], in nanostructures [15], and organic thin films on inorganic substrates [16].As the Si(100) surface is the most important template for semiconductor device fabrication, a detailed description of its electronic structure has been developed [17][18][19][20]. The formation of surface dimers results in a (2 Â 1) reconstruction at room temperature and a semiconducting surface with occupied and empty dangling-bond bands D up and D down .…”

From two-dimensional electron gas to localized charge: Dynamics of polaron formation in organic semiconductors

“…These interactions can lead to dynamic localization of the IPS, which has been studied by TR-ARPES in systems such as alkanes and polar solvents on metal surfaces [13][14][15][16], ionic liquids [17], and ionic crystals [18]. Recently, TR-ARPES has been used to study 2-D states at organic/metal interfaces [19][20][21] and organic semiconductor surfaces [22][23][24][25]. However, in most of the works on organic semiconductors, no temporal evolution of band structure has been observed.…”

Quantum confinement and anisotropy in thin-film molecular semiconductors

“…The n=2 IPS extends futher into the vacuum and has less bulk penetration at a noble metal surface. This commonly results in longer n=2 lifetimes and peak intensities that may be smaller by two orders of magnitude 33,34 . Although the lower intensity of the n=2 state is common to many systems, it is expected to be particularly true when both the n=1 and n=2 states are within the surface bandgap, as they are here due to the vacuum level shift and lowered workfunction.…”