Tunable optoelectronic and ferroelectric properties in Sc-based III-nitrides

Abstract

Sc-based III-nitride alloys were studied using Density Functional Theory with special quasi-random structures and were found to retain wide band gaps which stay direct up to x = 0.125 (ScxAl1-xN) and x = 0.375 (ScxGa1-xN). Epitaxial strain stabilization prevents spinodal decomposition up to x = 0.3 (ScxAl1-xN on GaN) and x = 0.24 (ScxGa1-xN on GaN), with critical thicknesses for strain relaxation ranging from 3 nm to near-infinity. The increase in Sc content introduces compressive in-plane stress with respect to AlN and GaN, and leads to composition- and stress-tunable band gaps and polarization, and ultimately introduces ferroelectric functionality in ScxGa1-xN at x = 0.625.

7 figures, submitted

References in corpus (2)

• Origin of the anomalous piezoelectric response in wurtzite Sc${}_x$Al${}_{1-x}$N alloys
• ScGaN Alloy Growth by Molecular Beam Epitaxy: Evidence for a Metastable Layered Hexagonal Phase

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