title: Imaging Atomic-Scale Clustering in III-V Semiconductor Alloys.
abstract: 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.
authors.affiliation: U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
authors.forename: Louise C
authors.identifier: 0000-0003-0073-6344
authors.initials: LC
authors.lastname: Hirst
authors.affiliation: U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
authors.forename: Nicole A
authors.identifier: 0000-0002-8753-5117
authors.initials: NA
authors.lastname: Kotulak
authors.affiliation: U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Tomasulo
authors.affiliation: U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
authors.forename: Josh
authors.initials: J
authors.lastname: Abell
authors.affiliation: Sotera Defense Solutions, Inc. , Annapolis Junction, Maryland 20701-1067, United States.
authors.forename: María
authors.initials: M
authors.lastname: González
authors.affiliation: U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Yakes
authors.affiliation: U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
authors.forename: Jerry R
authors.initials: JR
authors.lastname: Meyer
authors.affiliation: U.S. Naval Research Laboratory , 4555 Overlook Ave. SW, Washington, DC 20375, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Walters
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Cheng Yu
authors.initials: CY
authors.lastname: Song
authors.affiliation: University of California , Berkeley, California 94720, United States.
authors.forename: Petra
authors.initials: P
authors.lastname: Specht
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Peter
authors.initials: P
authors.lastname: Ercius
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Christian
authors.initials: C
authors.lastname: Kisielowski
keywords: HAADF; III−V alloys; InAlAsSb; STEM; clustering; image quantification; photovoltaics