Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 79: Electronic structure II

O 79.6: Talk

Thursday, March 17, 2011, 16:15–16:30, WIL C107

Band Structure of ZrS _x Se _2−x by ARPES — •Mohamed Moustafa, Alexander Paulheim, Christoph Janowitz, and Recardo Manzke — Institut für Physik, Humboldt-Universität zu Berlin, Berlin, Germany

The valence band structure of mixed samples of ZrS_x Se_2−x single crystals, where x varies from 0 to 2, has been studied by means of high-resolution angle-resolved photoelectron spectroscopy (ARPES) using synchrotron radiation. The crystals were found to be extrinsic n-type semiconductors with indirect bandgap. The composition dependence of the band structure is presented and discussed. A characteristic splitting of the chalcogen p-derived valence bands at the symmetric point A is observed. The size of the splitting shows to increases almost linearly as progressing from ZrS₂ to ZrSe₂ reaching  320 meV. Further, the energy gap values are estimated from the valence band maximum to the observed emission close to the conduction band minimum. The gaps are found to vary from 1.78 eV to 1.16 eV for ZrS₂ to ZrSe₂, respectively, and are compared to our previously reported optical values [1].

[1] M. Moustafa, Th. Zandt, C. Janowitz, and R. Manzke, Phy. Rev. B 80, 035206 (2009).