Facet-dependent optical and electrical properties of SrTiO3 wafers

Abstract

Transparent {100} and {111} SrTiO₃ wafers display a visually detectable color difference. They give considerably different absorption spectra, and have band gaps of 3.04 and 3.06 eV for the {100} and {111} wafers, respectively. Hence, wafer-scale crystals also possess facet-related optical behavior. Cuts over these wafers expose the {110} side faces for electrical conductivity measurements. The {111} face is much more conductive than the {110} face, while the {100} face has the lowest conductivity. Electrical connection for the {110}/{100} and {111}/{110} face combinations gives current-rectifying I–V curves, so potentially the wafers can be used to fabricate transistors utilizing the electrical facet effect.