Continuous Enhancement of Carrier Mobility in Strained Two-Dimensional Semiconductor Transistors

Two-dimensional (2D) semiconductors with atomic thickness hold promise as next-generation channel materials for transistors in the post-Moore era. However, the experimental mobility of most 2D semiconductors remains one order of magnitude lower than that of silicon. Strain engineering is widely recognized as an established strategy for modulating charge transport properties, particularly carrier mobility, in 2D semiconductors. Nevertheless, constrained by the multiscale challenge spanning from atomic-scale strain to micrometer-scale devices, achieving continuous modulation and enhancement of carrier mobility in 2D semiconductor transistors still poses a significant challenge. Here, we systematically investigated the influence of engineered strain on the electronic properties of atomically-thin molybdenum disulfide (MoS2). We transferred trilayer MoS2 onto SiNx/Si substrates with controlled roughness to induce precise and tunable lattice distortion. Such lattice distortion can effectively suppress electron–phonon scattering within the MoS2 channel, thereby modulating the band structure and electronic properties. We further fabricated back-gated MoS2 field-effect transistors (FETs) on the crested rough SiNx/Si substrates, which exhibited a continuously enhanced carrier mobility. Specifically, as the strain increased to 0.8%, the room-temperature mobility of the strained MoS2 FET was significantly enhanced to 326.9 cm2 V–1 s–1, representing a nearly 10-fold improvement over that of the non-strained MoS2 FET (30.6 cm2 V–1 s–1). Correspondingly, the maximum on-state current density of the strained MoS2 transistor increased by approximately 36 times compared to that of the non-strained device. Our work demonstrates that strain engineering can dramatically enhance the carrier mobility of 2D semiconductors, while being highly compatible with Si-based technology.