Year: 2026
Type: preprint
Abstract: Two-dimensional III-nitride alloys provide a composition-tunable platform for exploring thermoelectric transport and intrinsic electric-field tolerance. We combine first-principles electronic-structure calculations with semiclassical transport for ordered monolayer B$_{x}$Al$_{1-x}$N and B$_{x}$Ga$_{1-x}$N. State-dependent momentum relaxation times computed with AMSET include acoustic deformation-potential and piezoelectric scattering. Using a common, temperature-independent lattice thermal conductivity of 550 W/mK, we predict maximum thermoelectric figure of merit ZT>2.5 for selected p- and n-type monolayers and ZT>2 at 300~K for n-type B$_{0.25}$Ga$_{0.75}$N. Composition-dependent band curvature, screening, and scattering help interpret the different p- and n-type responses. Vacuum-referenced band alignments identify candidate modulation-doping partners for both carrier types; explicit hGaN/V$_2$O$_5$ calculations yield a hole surface density of approximately 1.6$\times10^{14}$ cm$^{-2}$. A separate phenomenological model using the band gap and maximum phonon frequency predicts intrinsic breakdown fields of 20.06 and 20.74 MVcm for the Al- and Ga-containing x=0.75 alloys, respectively. These results motivate further investigation for thermoelectric and high-field power-electronic applications. The ZT values apply to the specified scattering and lattice-conductivity models, while the breakdown estimates require validation for monolayers and do not resolve field direction.
Source: arXiv (Cornell University)
Author: Barr, Ariel R.
Institution: Massachusetts Institute of Technology
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223679863