Angle-resolved photoemission studies of the valence bands of ZrS Se2−

Abstract The electronic structure of the ternary layered transition metal dichalcogenide compounds of ZrS x Se 2− x , where 0 ≤ x ≤ 2, has been studied by means of high resolution angle-resolved photoemission spectroscopy (ARPES) used in conjunction with synchrotron radiation facilities. The crystals were grown by the chemical vapor transport technique using iodine as a transport agent. They are found to be degenerate extrinsic n -type semiconductors with an indirect bandgap character. The experimental valence band structure of the complete series of ZrS x Se 2− x is reported along the major symmetry azimuthal directions in the Brillouin zone parallel to the layers. The results show that the binding energies of the topmost valence band shift almost linearly with the composition parameter x . Further, an emission from the conduction band minimum observed just below the Fermi edge enabled us to estimate the energy gap values. The electronic structure deduced from the photoemission measurements are discussed and compared to band structure calculations.