Soft X‐Ray Absorption and Emission Spectroscopy in the Studies of Nanomaterials

Ionically Conducting Two‐Dimensional Heterostructures

“…In the following discussion, the parallel conductivities of BaF 2 thin films were investigated by such electrodes. [42] The parallel conductivity can also be accessed by dc measurement using four-point electrodes as shown in Figure 3. Here a dc current is applied by the two outer electrodes and the resulting voltage drop measured by a voltmeter with a high input impedance between the two inner electrodes (as the above geometry guarantees parallel current lines between the outer electrodes).…”

“…In these heterostructures, BaF 2 is always the first layer deposited, which ensures exclusive [111] orientation. In [40,42], effective measured parallel conductivities (s values increase continuously with decreasing thickness, indicating an accumulation layer due to substrate effects. That it is not the surface rather the solid-solid interface causing the accumulation is shown by substrate variation.…”

“…This anomalous increase of conductivity cannot be explained by a normal space charge effect, but suggests strain effects (elastic and/or plastic effects) what is supported by analysis of lattice constants of the films as a function of layer thickness. [42] In this case, variations of both carrier concentration and mobility are to be considered at the same time.…”

Nanocharacterization

“…The difference between the absorption and emission spectrum was used to determine the intrinsic band gap of 3.2 eV (TiO 2 ), w3.21 eV (1%), 3.35 eV (3%), and 3.47 eV (5%) allowing the size dependence of the nanomaterials and its electronic structure to be probed, using anatase titania [175]. Upon increased iron insertion into anatase Li x Ti 1Àx O 2 , charge transfer excitations with the unoccupied p-orbital of oxygen were derived covalently to the Ti d conduction band.…”

Electronic structure of room-temperature ferromagnetic Mg1−xFexOy thin films

“…XAS is a powerful technique to characterize unoccupied electronic states as a result of excitation of core electrons into the conduction band. 22 fluorescence yield (TFY) with a resolution of 0.2 eV. XES spectra have been acquired using a grating spectrometer at excitation energy of 585 eV.…”