Phonon-limited mobility in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-type single-layer MoS<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow/><mml:mn>2</mml:mn></mml:msub></mml:math>from first principles

Abstract

In the present work we calculate the phonon-limited mobility in intrinsic\nn-type single-layer MoS2 as a function of carrier density and temperature for T\n&gt; 100 K. Using a first-principles approach for the calculation of the\nelectron-phonon interaction, the deformation potentials and Fr\\"ohlich\ninteraction in the isolated MoS2 layer are determined. We find that the\ncalculated room-temperature mobility of ~410 cm^2 V^-1 s^-1 is dominated by\noptical phonon scattering via deformation potential couplings and the\nFr\\"ohlich interaction with the deformation potentials to the intravalley\nhomopolar and intervalley longitudinal optical phonons given by 4.1 x 10^8\neV/cm and 2.6 x 10^8 eV/cm, respectively. The mobility is weakly dependent on\nthe carrier density and follows a \\mu ~ T^-1 temperature dependence with \\gamma\n= 1.69 at room temperature. It is shown that a quenching of the characteristic\nhomopolar mode which is likely to occur in top-gated samples, boosts the\nmobility with 70 cm^2 V^-1 s^-1 and can be observed as a decrease in the\nexponent to \\gamma = 1.52. Our findings indicate that the intrinsic\nphonon-limited mobility is approached in samples where a high-kappa dielectric\nthat effectively screens charge impurities is used as gate oxide.\n

Keywords

Affiliated Institutions

• Technical University of Denmark DK

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