Non-thermal deposition of films and structures

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Synthesis of Switchable Thin Films / Layered Structures by Pulsed Laser Deposition

Scheme of the PLD setup enabling epitaxial growth of Ge-Sb-Te thin films at deposition rates up to 250 nm/min (SM: sample manipulator, TM: target manipulator, TMP: turbomolecular pump).
Overview of epitaxial formation of Ge2Sb2Te5 thin films with heterogeneous and homogeneous vacancy structures.
Influence of structural order of Ge2Sb2Te5 thin films on optical reflectivity contrast.

Rapidly growing data volumes require the continuous development and optimization of storage technologies. A promising storage technology that could overcome current limitations is based on phase-change memories (PCMs). PCMs employ electrically or optically operated memory cells, in which information is stored in a non-volatile manner by local switching of a phase-change material between an amorphous and a crystalline phase. By identifying the optical reflectivity or the electrical conductivity of the phase-change material (which differs between the amorphous and the crystalline phase), the stored information can be read out. The object of this group is the epitaxial growth of phase-change material thin films by nanosecond pulsed laser deposition (PLD) in order to fundamentally study material properties and associated experimental switching results with the grown structure. PLD growth of such kind of films comprises advantages like stoichiometric transfer, comparably high growth rates, as well as the positive influence of energetic (hyperthermal) species, being present within the laser ablation plasma plume, on the epitaxial film growth. By inducing phase transitions in epitaxial thin films it is aimed to obtain deeper insights into atomistic mechanisms playing a key role during switching. LINK


Selected publications

  • M. Behrens, A. Lotnyk, U. Roß, J. Griebel, P. Schumacher, J.W. Gerlach, B. Rauschenbach
    Impact of disorder on optical reflectivity contrast of epitaxial Ge2Sb2Te5 thin films

    Cryst. Eng. Comm. 20 (2018) 3688-3695

    doi: 10.1039/C8CE00534F

  • A. Lotnyk, I. Hilmi, U. Ross, B. Rauschenbach
    Van der Waals interfacial bonding and intermixing in GeTe-Sb2Te3-based superlattices

    Nano Res. 11 (2018) 1676-1686

  • I. Hilmi, A. Lotnyk, J.W. Gerlach, P. Schumacher, B. Rauschenbach
    Epitaxial formation of cubic and trigonal Ge-Sb-Te thin films with heterogeneous vacancy structures

    Mater. Design 115 (2017) 138-146

    doi: 10.1016/j.matdes.2016.11.003

  • I. Hilmi, A. Lotnyk, J.W. Gerlach, P. Schumacher, B. Rauschenbach
    Van-der-Waals epitaxy of layered chalcogenide Sb2Te3 thin films grown by pulsed laser deposition

    APL Mater. 5 (2017) 050701