2012/01/25 by Kristen Kaasbjerg, Kristian S. Thygesen, Karsten W. Jacobsen · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.85.115317
published as Phys. Rev. B 85, 115317 (2012) · Submitted to Phys. Rev. B
arxiv created 2012/01/25 · arxiv updated 2013/11/22
In the present work we calculate the phonon-limited mobility in intrinsic n-type single-layer MoS2 as a function of carrier density and temperature for T > 100 K. Using a first-principles approach for the calculation of the electron-phonon interaction, the deformation potentials and Fröhlich interaction in the isolated MoS2 layer are determined. We find that the calculated room-temperature mobility of ~410 cm2 V-1 s-1 is dominated by optical phonon scattering via deformation potential couplings and the Fröhlich interaction with the deformation potentials to the intravalley homopolar and intervalley longitudinal optical phonons given by 4.1 x 108 eV/cm and 2.6 x 108 eV/cm, respectively. The mobility is weakly dependent on the carrier density and follows a μ~ T-1 temperature dependence with γ= 1.69 at room temperature. It is shown that a quenching of the characteristic homopolar mode which is likely to occur in top-gated samples, boosts the mobility with 70 cm2 V-1 s-1 and can be observed as a decrease in the exponent to γ= 1.52. Our findings indicate that the intrinsic phonon-limited mobility is approached in samples where a high-kappa dielectric that effectively screens charge impurities is used as gate oxide.