Giant polarization charge density at lattice-matched GaN/ScN interfaces

Abstract

Rocksalt ScN is a semiconductor with a small lattice mismatch to wurtzite GaN. Within the modern theory of polarization, ScN has a nonvanishing formal polarization along the [111] direction. As a result, we demonstrate that an interface between (0001) GaN and (111) ScN exihibts a large polarization discontinuity of $-$1.358 $\mathrm{C}{\mathrm{m}}^{-2}$. Interfaces between ScN and wurtzite III-nitrides will exhibit a high-density electron gas on the (000$\bar{1}$) GaN interface or a hole gas on the (0001) GaN interface, with carrier concentrations up to $8.5\times 10^{14}$ cm${}^{-2}$. The large polarization difference and small strain makes ScN a desirable choice for polarization-enhanced tunnel junctions within the III-nitride materials system. The large sheet carrier densities may also be useful for contacts or current spreading layers.

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Applied Physics Letters {\bf 115}, 232103 (2019) and may be found at https://aip.scitation.org/doi/10.1063/1.5126717