The ordered (100) surface of layered In4Se3 single crystals is characterized by semiconducting quasi-one-dimensional indium (In) chains. A band with significant dispersion in the plane of the surface is observed near the valence band maximum. The band exhibits an anisotropic dispersion with ∼1eV band width along the In chain direction. The dispersion of this band is largely due to the hybridization of In-s and Se-p orbitals, but the hybridization between In-s and Se-p and In-p and Se-p orbitals is also critical in establishing the band gap.

Losovyj, Yaroslav B.; Makinistian, L.; Albanesi, E. A.; Pethukov, A. G.; Liu, Jing; Galiy, P.; Dveriy, O. R.; and Dowben, Peter A., "The anisotropic band structure of layered In 4 Se 3 (001)" (2008 There is discernable and significant band dispersion along both high symmetry directions for cleaved ordered surfaces of the layered In 4 Se 3 ͑001͒. The extent of dispersion of approximately 1 eV is observed along the surface chain rows, and about 0.5 eV perpendicular to the surface "furrows," consistent with theoretical expectations. A possible surface state exists at the surface Brillouin zone edge, in the direction perpendicular to the chains, in a gap of the projected bulk band structure. Excluding the possible surface state, the experimental hole mass is 5.5 times greater along the chains than perpendicular to the chains, but the dispersion is easier to discern.

The surface termination of In4Se3(001) and the interface of this layered trichalcogenide, with Au, was examined using x-ray photoemission spectroscopy. Low energy electron diffraction indicates that the surface is highly crystalline, but suggests an absence of C2v mirror plane symmetry. The surface termination of the In4Se3(001) is found, by angle-resolved x-ray photoemission spectroscopy, to be In, which is consistent with the observed Schottky barrier formation found with this n-type semiconductor. Transistor measurements confirm earlier results from photoemission, suggesting that In4Se3(001) is an n-type semiconductor, so that Schottky barrier formation with a large work function metal, such as Au, is expected. The measured low carrier mobilities could be the result of the contacts and would be consistent with Schottky barrier formation.

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