摘要
设计了一种将 β FeSi2 颗粒埋入非故意掺杂Si中的Sip π n二极管来确定 β FeSi2 Si异质结的能隙差 .当二极管处于正向偏置时 ,通过Sin p-结注入的电子扩散到 β FeSi2 并由于Si与 β FeSi2 之间的能隙差而受到限制 ,电荷在异质结的积累反过来阻挡了电子的继续扩散 ,将电子局域化在靠近Sin p-结的 p- Si区 .少子的局域化减少了非辐射复合的途径 ,Si和β FeSi2 的发光增强 ,淬灭速率变慢 ,在室温低电流下仍可得到Si和 β FeSi2 电致发光 .Si和 β FeSi2 发光强度的比率对温度的依存性表明同型异质结对电子限制能力的减弱符合热发射模型 ,由此确定出Si和 β FeSi2 异质结导带带阶差为 0 2eV .
A Si p-π-n diode with β-FeSi 2 particles embedded in the unintentionally doped Si (p--type) was designed for determining the band offset at β-FeSi 2-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-FeSi 2 particles due to the band offset.The storage charge at the β-FeSi 2-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-FeSi 2 quenching slowly up to room temperature.The temperature dependent ratio of EL intensity of β-FeSi 2 to Si indicates the loss of electron confinement following thermal excitation model.The conduction band offset between Si and β-FeSi 2 is determined to be about 0 2eV.
基金
福建省青年科技人才创新资助项目 (编号 :2 0 0 4J0 2 1)~~
