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HL: Fachverband Halbleiterphysik

HL 22: Heterostructures, Interfaces and Surfaces

HL 22.5: Vortrag

Mittwoch, 7. September 2022, 16:00–16:15, H33

Interplay of anomalous strain relaxation and minimization of polarization changes at nitride semiconductor heterointerfaces — Yuhan Wang^1,2, •Michael Schnedler^1,2, Qianqian Lan^1,2, Fengshan Zheng^1,2, Lars Freter^1,2, Yan Lu^1,2, Uwe Breuer³, Holger Eisele⁴, Jean-François Carlin⁵, Raphaël Butté⁵, Nicolas Grandjean⁵, Rafal E. Dunin-Borkowski^1,2, and Philipp Ebert^1,2 — ¹Peter Grünberg Institut, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — ²Ernst Ruska Centrum, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — ³Zentralinstitut für Engineering, Elektronik und Analytik (ZEA-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — ⁴Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany — ⁵Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland

Polarization and electron affinity changes at Al_0.06Ga_0.94N/GaN and In_0.05Ga_0.95N/Al_0.06Ga_0.94N interfaces are quantified by combining off-axis electron holography in transmission electron microscopy, scanning tunneling microscopy, and simulations of the electrostatic potential and electron phase maps. The In_0.05Ga_0.95N/Al_0.06Ga_0.94N interface reveals, as expected, biaxial relaxation as well as polarization and electron affinity changes. However, at the Al_0.06Ga_0.94N/GaN interface anomalous lattice relaxations and vanishing polarization and electron affinity changes occur, whose underlying physical origin is anticipated to be total energy minimization by the minimization of Coulomb interactions between the polarization-induced interface charges.