Nanoparticle-Seeding Approach to Buried (Semi) Metal Film Growth

摘要

We explored an entirely new growth mode for epitaxially-integrating (semi)metallic films with high-quality III-V semiconductors, which could be particularly important to the future of multi-modal sensors, specifically vertically-integrating a diversity of sensing modes onto a single pixel. ErAs and many of the other rare-earth monopnictides (generally denoted as RE-V) are rocksalt semimetals that can be grown epitaxially on zinc-blende III-V substrates, with thermodynamically stable interfaces. However, the rotational symmetry mismatch between the III-V and ErAs results in a high density of planar defects in III-V layers grown on ErAs, akin to the challenges associated with GaAs growth on silicon. To circumvent this limit, we employed a seed layer of buried ErAs nanostructures. ErAs layer growth then proceeds sub-surface, with a GaAs capping layer floating above. The advantage of this technique is that the GaAs capping layer remains registered to the underlying substrate, preventing planar defect formation during subsequent III-V growth.