Bilayer MoS2 is a promising channel candidate for extending Moore’s law,owing to its optimal channel thickness and improved suppression of extrinsic scattering compared to monolayers.However,its intrinsic phonon-limi...Bilayer MoS2 is a promising channel candidate for extending Moore’s law,owing to its optimal channel thickness and improved suppression of extrinsic scattering compared to monolayers.However,its intrinsic phonon-limited electron mobility is severely limited by enhanced K–Q intervalley scattering arising from the multivalley conduction band feature inherent to the bilayer structure.To overcome this bottleneck,we propose a“valley separation engineering”strategy that combines a twist angle near 30°with applied stress.Our first-principles calculations demonstrate that although valley separation can be continuously increased using this strategy,the electron mobility saturates at∼200 cm^(2)⋅V^(−1)⋅s^(−1).The saturation is attributed to the competition between the reduced effective mass and enhanced intravalley scattering induced by phonon softening once the detrimental intervalley scattering is effectively suppressed by sufficient valley separation.This study establishes a theoretical upper limit for the intrinsic electron transport of bilayer MoS2 masked by severe intervalley scattering.展开更多
基金supported by the National Key R&D Program of China (Grant No.2022YFA1402503)the High Performance Computing Center of Jilin University,China。
文摘Bilayer MoS2 is a promising channel candidate for extending Moore’s law,owing to its optimal channel thickness and improved suppression of extrinsic scattering compared to monolayers.However,its intrinsic phonon-limited electron mobility is severely limited by enhanced K–Q intervalley scattering arising from the multivalley conduction band feature inherent to the bilayer structure.To overcome this bottleneck,we propose a“valley separation engineering”strategy that combines a twist angle near 30°with applied stress.Our first-principles calculations demonstrate that although valley separation can be continuously increased using this strategy,the electron mobility saturates at∼200 cm^(2)⋅V^(−1)⋅s^(−1).The saturation is attributed to the competition between the reduced effective mass and enhanced intravalley scattering induced by phonon softening once the detrimental intervalley scattering is effectively suppressed by sufficient valley separation.This study establishes a theoretical upper limit for the intrinsic electron transport of bilayer MoS2 masked by severe intervalley scattering.
