First-principles Study of Carrier Mobility and Strain Effect in MX (M=Sn, Pb; X=P, As) Monolayers

Abstract The pursuit of two-dimensional semiconductor materials that feature tunable electronic structures and high mobility is crucial for advancing nanoelectronic and optoelectronic devices. In this study, the MX monolayers (M = Sn, Pb; N = P, As) are investigated with first-principles calculations based on Boltzmann transport theory. The results show that SnP, SnAs, and PbAs all exhibit indirect band gaps, whereas PbP is the only semiconductor with a direct band gap. One important finding is that intravalley scattering has a significant impact on electron–phonon coupling. Interestingly, changes in carrier concentration do not affect the electron mobility within these MX monolayers, with SnP exhibiting the highest electron mobility among them. Subsequently, the SnP under a 6% biaxial strain is further explored and the results demonstrated a considerable increase in electron mobility to 2,511.9 cm 2 V − 1 s − 1 , which is attributable to decreased scattering. This suggests that MX monolayers, especially SnP, are promising options for 2D semiconductor materials in the future.