First-Principles Calculation of Alloy Scattering and n-type Mobility in Strained GeSn

Abstract

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 $10^5$ cm${}^2$/(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.

References in corpus (2)

• Monolithic Infrared Silicon Photonics: The Rise of (Si)GeSn Semiconductors
• Ultra-high mobility two-dimensional electron gas in a SiGe/Si/SiGe quantum well

Cited by in corpus (1)

• Epitaxial SiGeSn alloys for CMOS-compatible thermoelectric devices