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HL: Fachverband Halbleiterphysik

HL 44: Nitrides: Preparation and characterization II

HL 44.5: Vortrag

Donnerstag, 21. März 2024, 15:00–15:15, EW 015

Molecular beam epitaxy of (Al,Sc)N nanowires — •Philipp John, Oliver Brandt, Achim Trampert, Lutz Geelhaar, and Thomas Auzelle — Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany

To extend the functionalities of classical III-nitride devices, combinations with transition metal nitrides are sought. Alloying AlN with ScN, for instance, can enhance its piezoelectric coefficient by up to a factor of 5, provided that the hexagonal wurtzite phase is maintained. Wurtzite (Al,Sc)N is thus a promising material for new types of surface/bulk acoustic devices, piezoelectric energy harvesters and high electron mobility transistors.

In this contribution, we demonstrate (Al,Sc)N growth on self-assembled AlN and GaN nanowire stems by molecular beam epitaxy for a wide range of concentrations. Wurtzite (Al,Sc)N is stabilized at low to moderate Sc concentrations, while a phase transition to the cubic rocksalt structure is found for high Sc concentrations. We will discuss the possibility of growing either axial or core/shell nanowire structures, depending on the (Al,Sc)N growth conditions. Axial nanowire structures offer the preferred geometry for piezoelectric devices, while core/shell nanowires are promising for realizing heterostructures combining group III-nitrides and transition metal nitrides.

Keywords: AlScN; self-assembly; nanowires; molecular beam epitaxy