Dresden 2020 – scientific programme

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DS: Fachverband Dünne Schichten

DS 37: Focus Session: Functional Metal Oxides for Novel Applications and Devices II (joint session HL/DS)

DS 37.9: Talk

Thursday, March 19, 2020, 12:30–12:45, POT 81

Tin-assisted growth of κ-(Al_xGa_1−x)₂O₃/(In_xGa_1−x)₂O₃ superlattice heterostructures by pulsed laser deposition — •Max Kneiss, Philipp Storm, Anna Hassa, Daniel Splith, Chris Sturm, Holger von Wenckstern, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik

The orthorhombic κ-phase of Ga₂O₃ possesses a similarly high bandgap of  5 eV as the thermodynamically stable β-phase, but further is expected to exhibit a high spontaneous electrical polarization of 23 µC/cm² [1]. Polarization differences at interfaces of κ-phase heterostructures can be utilized for polarization doping to localize a 2DEG that typically features large carrier densities as well as high mobility. We present the coherent growth of κ-(Al_xGa_1−x)₂O₃/(In_xGa_1−x)₂O₃ quantum-well (QW) superlattices on c-sapphire substrates by pulsed laser deposition. Tin containing targets were necessary for the stabilization of the orthorhombic phase [2]. We found narrow superlattice oscillations up to the ninth order and up to x≈0.5 in XRD 2θ-ω scans as well as in reciprocal space maps for up to 15 layer pair superlattices confirming excellent crystal quality and abrupt interfaces. The evolution of superlattice oscillations as well as the optical properties will be evaluated in dependence on the QW and barrier width as well as on the composition of the QW and barrier layers. AFM measurements confirm smooth surface morphology for all samples. [1] Maccioni et al., Appl. Phys. Expr. 9, 041102 (2016) [2] Kneiß et al., APL Materials 7, 022516 (2019)