Interface Analysis of MOCVD Grown GeTe/Sb2Te3 and Ge-Rich Ge-Sb-Te/Sb2Te3 Core-Shell Nanowires

Controlling material thickness and element interdiffusion at the interface is crucial formany applications of core-shell nanowires. Herein, we report the thickness-controlled and conformalgrowth of a Sb2Te3 shell over GeTe and Ge-rich Ge-Sb-Te core nanowires synthesized via metalorganicchemical vapor deposition (MOCVD), catalyzed by the Vapor-Liquid-Solid (VLS) mechanism.The thickness of the Sb2Te3 shell could be adjusted by controlling the growth time without altering thenanowire morphology. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniqueswere employed to examine the surface morphology and the structure of the nanowires. The studyaims to investigate the interdiffusion, intactness, as well as the oxidation state of the core-shellnanowires. Angle-resolved X-ray photoelectron spectroscopy (XPS) was applied to investigate thesurface chemistry of the nanowires. No elemental interdiffusion between the GeTe, Ge-rich Ge-Sb-Tecores, and Sb2Te3 shell of the nanowires was revealed. Chemical bonding between the core and theshell was observed.