Properties of GaN nanowires with Sc_xGa_1−xN insertion

Abstract

We report the first GaN nanowire structure incorporating a GaN/ScxGa1–xN axial heterostructure. A 20 nm ScxGa1−xN layer was inserted into GaN nanowires grown by a catalyst‐free self‐assembled method using plasma‐assisted molecular beam epitaxy (PA‐MBE). The insertion was characterised by energy dispersive X‐ray spectroscopy in the scanning transmission electron microscope (STEM‐EDX). High resolution electron microscopy revealed the ScxGa1−xN to have a wurtzite crystal structure as expected at this composition. Cathodoluminescence (CL) imaging in the scanning electron microscope (SEM) at 77 K revealed an emission peak at 377 nm which is not present in samples without the ScxGa1−xN insertion. A correlative study using STEM‐EDX and low temperature SEM‐CL indicates a direct link between the 377 nm emission and the ScxGa1−xN insertion. This is tentatively attributed to a type‐II band offset between the GaN and the ScxGa1−xN insertion.