Measurements of Carrier Confinement at β-FeSi2-Si Heterojunction by Electroluminescence

A Si p-π-n diode with β-FeSi2 particles embedded in the unintentionally doped Si (p－type) was designed for determining the band offset at β-FeSi2-Si heterojunction.When the diode is under forward bias,the electrons injected via the Si np－ junction diffuse to and are confined in the β-FeSi2 particles due to the band offset.The storage charge at theβ-FeSi2-Si heterojunction inversely hamper the further diffusion of electrons,giving rise to the localization of electrons in the p－Si near the Si junction,which prevents them from nonradiative recombination channels.This results in electroluminescence (EL) intensity from both Si and β-FeSi2 quenching slowly up to room temperature.The temperature dependent ratio of EL intensity of β-FeSi2 to Si indicates the loss of electron confinement following thermal excitation model.The conduction band offset between Si and β-FeSi2 is determined to be about 0.2eV.