1303.3745 (Siyuan Zhang et al.)

Tunable optoelectronic and ferroelectric properties in Sc-based
III-nitrides    [PDF]

Siyuan Zhang, David Holec, Wai Y. Fu, Colin J. Humphreys, Michelle A. Moram

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.

View original: http://arxiv.org/abs/1303.3745