Journal Article

FZJ-2022-02239

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Scaling and Confinement in Ultrathin Chalcogenide Films as Exemplified by GeTe

Kerres, P. (Corresponding author) ; Zhou, Y. ; Vaishnav, H.FZJ* ; Raghuwanshi, M.FZJ* ; Wang, J. ; Häser, M. ; Pohlmann, M. ; Cheng, Y. ; Schön, C.-F. ; Jansen, T.FZJ* ; Bellin, C. ; Bürgler, D. E.FZJ* ; Jalil, A. R.FZJ* ; Ringkamp, C.FZJ* ; Kowalczyk, H. ; Schneider, C. M.FZJ* ; Shukla, A. ; Wuttig, M. (Corresponding author)FZJ*

2022
Wiley-VCH Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/31259  doi:10.1002/smll.202201753

Abstract: Chalcogenides such as GeTe, PbTe, Sb2Te3, and Bi2Se3 are characterized by an unconventional combination of properties enabling a plethora of applications ranging from thermo-electrics to phase change materials, topological insulators, and photonic switches. Chalcogenides possess pronounced optical absorption, relatively low effective masses, reasonably high electron mobilities, soft bonds, large bond polarizabilities, and low thermal conductivities. These remarkable characteristics are linked to an unconventional bonding mechanism characterized by a competition between electron delocalization and electron localization. Confinement, that is, the reduction of the sample dimension as realized in thin films should alter this competition and modify chemical bonds and the resulting properties. Here, pronounced changes of optical and vibrational properties are demonstrated for crystalline films of GeTe, while amorphous films of GeTe show no similar thickness dependence. For crystalline films, this thickness dependence persists up to remarkably large thicknesses above 15 nm. X-ray diffraction and accompanying simulations employing density functional theory relate these changes to thickness dependent structural (Peierls) distortions, due to an increased electron localization between adjacent atoms upon reducing the film thickness. A thickness dependence and hence potential to modify film properties for all chalcogenide films with a similar bonding mechanism is expected.

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Contributing Institute(s):

1. JARA Institut Green IT (PGI-10)
2. Elektronische Eigenschaften (PGI-6)
3. Halbleiter-Nanoelektronik (PGI-9)

Research Program(s):

1. 5233 - Memristive Materials and Devices (POF4-523) (POF4-523)

Appears in the scientific report 2022

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Essential Science Indicators ; IF >= 15 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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