We use first-principles electronic-structure theory to determine the intra- and inter-valley electron-alloy scattering parameters in n-type GeSn alloys. These parameters are used to determine the alloy scattering contributions to the n-type electron mobility of GeSn at 300K and 15K using a first iteration of the Boltzmann transport equation in the relaxation time approximation. For unstrained GeSn, we find that a Sn concentration of at least 13.5% is needed to achieve an electron mobility greater than that of Ge. Our results show that the mobility of GeSn can be over 25 times higher than the mobility of Ge, or 105 cm2/(Vs). At 15K, less than 6% Sn incorporation into Ge quadruples its mobility, which suggests GeSn has potential applications as a high mobility 2D electron gas. Applying biaxial tensile strain to GeSn further increases the mobility and at a lower Sn content than in unstrained GeSn.
@article{arxiv.2410.14478,
title = {First-Principles Calculation of Alloy Scattering and n-type Mobility in Strained GeSn},
author = {Kevin Sewell and Felipe Murphy-Armando},
journal= {arXiv preprint arXiv:2410.14478},
year = {2025}
}