Structure of Si(111)-In Nanowires Determined from the Midinfrared Optical Response

Abstract

The anisotropic optical response of Si(111)-(4×1)/(8×2)-In in the midinfrared, where ab initio studies predict significant changes in the band structure between competing models of this important quasi-1D system, has been measured using infrared spectroscopic ellipsometry (IRSE) and reflection anisotropy spectroscopy (RAS). Both IRSE and RAS of the (8×2) phase show that the anisotropic Drude tail of the (4×1) phase is replaced by two peaks at 0.50 and 0.72 eV, which appear in ab initio optical response calculations for the hexagon model of the (8×2) structure, but not the trimer model.