Angle-resolved photoelectron emission from three-dimensionally aligned Si{111} facet-line structure: Modeling and observation of geometrical effects

Angle-resolved photoelectron spectroscopy (ARPES) has been widely applied to planar surfaces; however, its extension to three-dimensional (3D) structured materials remains limited due to complex geometrical effects. In this study, we investigate photoelectron emission from a well-defined 3D-Si{111} facet-line structure by combining high-resolution ARPES measurements with a geometrical model. The model explicitly incorporates photon irradiation and photoelectron emission processes, enabling quantitative prediction of shadowing and hindrance effects arising from the 3D geometry. Experimentally, atomically well-ordered Si(111)7× 7 surfaces were formed on the facet-line structures and confirmed by low-energy electron diffraction. ARPES measurements reveal characteristic angular intensity modulations, particularly in the S 3 surface state, including asymmetric suppression and reduced intensity in specific angular regions. These observations show reasonable agreement with the model predictions, supporting the interpretation that geometry-induced shadowing effects contribute to the measured photoelectron intensity distribution. The proposed framework establishes a practical approach for interpreting ARPES data from 3D structured materials and offers a guideline for designing experimental configurations to extract intrinsic electronic properties.