Necessity of Epitaxial Growth of β-FeSi2 Thin Films in Formation of n-Type β-FeSi2/p-Type Si Heterojunction Photodiodes

Abstract

n-Type β-FeSi2 thin films were epitaxially and non-epitaxially grown on p-type Si(111) substrates by facing-targets direct-current sputtering (FTDCS) at a substrate temperature of 600{degree sign}C. Whereas the n-type epitaxial β-FeSi2/p-type Si heterojunctions exhibited a typical rectifying behavior with a rectification ratio of more than two orders of magnitude at bias voltages between {plus minus}1 V, the heterojunctions comprising non-epitaxial β-FeSi2 films rarely exhibited rectifying action. The epitaxial growth of β-FeSi2 is an significant factor for forming the heterojunction diodes.