Filtern
Dokumenttyp
Institut
Resonant inelastic soft x-ray scattering (RIXS) was used to study the electronic structure of solid
cysteine films. A RIXS map approach, i.e., plotting the x-ray emission intensity as a function of
excitation and emission energy, allows us to separate the contributions of the three chemically nonequivalent
carbon atoms in cysteine. In particular, we can identify orbitals localized near the photoexcited
atoms, as well as orbitals that are delocalized over the entire molecule.
Spatial variations in the chemical composition of the (Zn,Mg)O/CuIn(S,Se)2 thin-film solar cell interface were studied by photoemission electron microscopy (PEEM). Energy filtered PEEM
images indicate significant differences in the magnesium and zinc distribution. Local photoemission measurements reveal a relative difference in the derived Mg/(ZnþMg) composition of the (Zn,Mg)O material of up to (11.460.7)%, which can be expected to induce band gap
fluctuations of (60630) meV. Furthermore, local areas with significant accumulations of sodium could be observed.
The μm-scale spatial distribution of the elements of polycrystalline Cu(In1− x Ga x )Se2 absorber surfaces is examined using x-ray photoelectron emission microscopy. The chemical composition varies from grain to grain, and a direct, linear anticorrelation between the In 3d and Ga 2p photoemission line intensities is observed. The line intensities are interpreted in terms of a varying value of x= Ga/(In+ Ga); the band gaps calculated from the inferred compositions of the grains are shown to be normally distributed with a standard deviation of 40 meV.