论文标题
氦结合稳定直接硅质硅
Helium Incorporation Stabilized Direct-gap Silicides
论文作者
论文摘要
由于在许多技术相关的领域中的潜在应用，对基于直接SI的直接SI半导体的搜索引起了人们的极大兴趣。这项工作研究了将HE的合并为在SI中形成直接带隙的可能途径。结构预测和第一原理的计算表明他在高压下与Si反应，形成稳定的化合物Si2He和Si3He。这两种化合物都有主机 - 乐器结构，该结构包括一个频道式的SI主机框架，里面装有He Atoms。去除HE后，可以将两种化合物中的SI框架持续到环境压力，形成两个纯Si同素异形。 Si-He化合物和Si同素异形体均表现出0.84-1.34 eV的直接或准直接导条间隙，接近太阳能电池应用的最佳值（〜1.3 eV）。分析表明，具有电偶极转换的SI2HE允许带隙比Diamond Cubic Si具有更高的吸收能力，这使其成为薄膜太阳能电池的有前途的候选材料。
The search of direct-gap Si-based semiconductors is of great interest due to the potential application in many technologically relevant fields. This work examines the incorporation of He as a possible route to form a direct band gap in Si. Structure predictions and first-principles calculations have shown that He reacts with Si at high pressure, to form the stable compounds Si2He and Si3He. Both compounds have host-guest structures consisting of a channel-like Si host framework filled with He guest atoms. The Si frameworks in two compounds could be persisted to ambient pressure after removal of He, forming two pure Si allotropes. Both Si-He compounds and both Si allotropes exhibit direct or quasi-direct band gaps of 0.84-1.34 eV, close to the optimal value (~1.3 eV) for solar cell applications. Analysis shows that Si2He with an electric-dipole-transition allowed band gap possesses higher absorption capacity than diamond cubic Si, which makes it to be a promising candidate material for thin-film solar cell.
