Research of energy structure of crystalline compounds in Ag(Tl)-As(Р)-S(Se) systems

The paper presents the results of studying the peculiarities of formation of the valence band and the conduction band of crystalline compounds in Ag(Tl)-As(P)-S(Se) systems with sp3-type bond by using the photoelectron spectroscopy method. From the spectral distribution of photoemission by energy, the crystal photoelectron work function hν0 was determined. It was shown that the use of a limited basis (only ionization potentials of atoms and interatomic distances) for crystals with sp3-type bond within the framework of the LCAO model gives sufficiently accurate results of the position of the valence band top and the electron affinity value. Calculations show that the position of the valence band top defines the bonds of As-S(Se) and P-S(Se) atoms, while the hybridized orbitals of Ag and Tl atoms are formed in the conduction band.