Photoemission spectroscopy

About: Photoemission spectroscopy is a research topic. Over the lifetime, 10821 publications have been published within this topic receiving 250888 citations. The topic is also known as: photoelectron spectroscopy & PES.

Determination of the branch-point energy of InN: Chemical trends in common-cation and common-anion semiconductors

Abstract: Bulk and surface electronic properties of Si-doped InN are investigated using high-resolution x-ray photoemission spectroscopy, optical absorption spectroscopy, and quasiparticle corrected density functional theory calculations. The branch point energy in InN is experimentally determined to lie $1.83\ifmmode\pm\else\textpm\fi{}0.10\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ above the valence-band maximum. This high position relative to the band edges is used to explain the extreme fundamental electronic properties of the material. Far from being anomalous, these properties are reconciled within chemical trends of common-cation and common-anion semiconductors.

X-ray photoemission determination of the Schottky barrier height of metal contacts to n-GaN and p-GaN

Abstract: Synchrotron radiation-based x-ray photoemission spectroscopy was used to study the surface Fermi level position within the band gap for thin metal overlayers of Au, Al, Ni, Ti, Pt, and Pd on n–GaN and p–GaN. Nonequilibrium effects were taken into account by measuring the Fermi edge of the metal overlayer. There are two different behaviors observed for the six metals studied. For Au, Ti, and Pt, the surface Fermi level lies about 0.5-eV higher in the gap for n-type than for p-type GaN. For Ni, Al, and Pd, the surface Fermi level position is independent of doping, but varies from one metal to the other. Results for Ni, Pd, and Al fit a modified Schottky–Mott theory, while Au, Ti, and Pt demonstrate a more complex behavior. Atomic force microscopy was used along with photoemission to investigate the growth mode of each metal on the GaN surface.

Vibronic coupling in the ground cationic state of naphthalene: A laser threshold photoelectron [zero kinetic energy (ZEKE)‐photoelectron] spectroscopic study

Abstract: The two‐color (1+1’) threshold photoelectron spectra of naphthalene in a supersonic free jet have been recorded via nine vibronic levels of the S1 electronic state up to about 1420 cm−1 above the S1 band origin. The threshold photoelectron spectra recorded via the S1 band origin and via totally symmetric ag vibronic levels show significant intensity in Δν=+1 transitions in nontotally symmetric vibrations having b1g symmetry indicating that the ionization transition gains significant intensity through a vibronic coupling mechanism between the two lowest doublet cationic states. The strongest departure from the expected Δν=0 propensity in the threshold photoelectron spectra occurs through excitation of the totally symmetric 8 mode having ag symmetry indicating that a considerable displacement occurs along the normal coordinate of this 8 mode upon ionization from the S1 state. The superior resolution of the threshold photoelectron technique over conventional photoelectron methods has allowed accurate values ...

Energy position of 4f levels in rare-earth metals

Abstract: The energy position of the occupied and unoccupied 4f levels relative to the Fermi energy is studied for the rare-earth metals. This is done by treating the excited state as an impurity in an otherwise perfect crystal. This picture is first considered in the complete screening approximation. In this approximation thermochemical data can be used directly to give energy values for the unoccupied f levels which are accurate to +- 0.05 eV; for the occupied f levels the uncertainty is somewhat larger. The obtained values are then compared with recent x-ray photoemission spectroscopy (XPS) and Bremsstrahlung isochromal spectroscopy data. The deviations found are discussed in terms of impurity effects left out in the complete screening approximation. When these effects are included a general good agreement with experiment is obtained. The consistency found in the XPS results is utilized for an improved estimation of the fourth ionization energy of the rare earths.