U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
Sotera Defense Solutions, Inc. , Annapolis Junction, Maryland 20701-1067, United States.
ACS Nano. 2017 Mar 28;11(3):2734-2741. doi: 10.1021/acsnano.6b07732. Epub 2017 Mar 16.
Quaternary alloys are essential for the development of high-performance optoelectronic devices. However, immiscibility of the constituent elements can make these materials vulnerable to phase segregation, which degrades the optical and electrical properties of the solid. High-efficiency III-V photovoltaic cells are particularly sensitive to this degradation. InAlAsSb lattice matched to InP is a promising candidate material for high-bandgap subcells of a multijunction photovoltaic device. However, previous studies of this material have identified characteristic signatures of compositional variation, including anomalous low-energy photoluminescence. In this work, atomic-scale clustering is observed in InAlAsSb via quantitative scanning transmission electron microscopy. Image quantification of atomic column intensity ratios enables the comparison with simulated images, confirming the presence of nonrandom compositional variation in this multispecies alloy.
四元合金对于高性能光电器件的发展至关重要。然而，组成元素的不混溶性可能使这些材料容易发生相分离，从而降低固体的光学和电学性能。高效的 III-V 光伏电池对此类退化尤为敏感。晶格匹配于 InP 的 InAlAsSb 是多结光伏器件的高带隙子电池的有前途的候选材料。然而，对该材料的先前研究已经确定了组成变化的特征特征，包括异常的低能量光致发光。在这项工作中，通过定量扫描透射电子显微镜观察到 InAlAsSb 中的原子尺度聚集。原子列强度比的图像量化可与模拟图像进行比较，从而证实了这种多组分合金中存在非随机的组成变化。
