Antonín Šimůnek

Electronic structure of silicon nitride

Abstract The electronic structure of valence and conduction bands of silicon nitride SiNx layer deposited on a silicon substrate was studied using X-ray photoelectron spectroscopy (XPS) and X-ray bremsstrahlung isochromat spectroscopy (BIS), respectively, and compared with the density of states (DOS) taken from the literature. In the isochromat spectrum measured at photon energy 5415 eV, a strong maximum at 9.7 eV and a weak extended structure in the energy range up to 200 eV above the BIS edge were observed. A theoretical calculation of extended X-ray bremsstrahlung isochromat fine structure (EXBIFS) for silicon nitride has been performed using a multiple scattering method and partial probabilities of X-ray bremsstrahlung transitions calculated for continuum states in a dipole approximation. The results have shown that the X-ray bremsstrahlung isochromat fine structure for silicon nitride appears mainly due to electron transitions to the s states localized near Si ions.

The electronic structure of CuGaSe2 and ZnGeAs2: Experimental and calculated K emission bands

Abstract We present Cu K, Zn K, Ga K, Ge K, As K and Se K X-ray emission bands of the isostructural and isoelectronic ternary compounds CuGaSe2 and ZnGeAs2. The measured spectra are compared with ab initio calculations and good agreement between theory and experiment is found. Since the local structure of corresponding atoms in both compounds is the same, the differences in spectra delineate the different behaviour of constituent atoms in the chemical bond.