Two-Dimensional Cold Electron Transport for Steep-Slope Transistors
Maomao Liu, Hemendra Nath Jaiswal, Simran Shahi, Sichen Wei, Yu Fu, Chaoran Chang, Anindita Chakravarty, Xiaochi Liu, Cheng Yang, Yanpeng Liu, Young Hee Lee, Vasili Perebeinos, Fei Yao, Huamin Li
Abstract
Room-temperature Fermi–Dirac electron thermal excitation in conventional three-dimensional (3D) or two-dimensional (2D) semiconductors generates hot electrons with a relatively long thermal tail in energy distribution. These hot electrons set a fundamental obstacle known as the “Boltzmann tyranny” that limits the subthreshold swing (SS) and therefore the minimum power consumption of 3D and 2D field-effect transistors (FETs). Here, we investigated a graphene (Gr)-enabled cold electron injection where the Gr acts as the Dirac source to provide the cold electrons with a localized electron density distribution and a short thermal tail at room temperature. These cold electrons correspond to an electronic refrigeration effect with an effective electron temperature of ∼145 K in the monolayer MoS2, which enables the transport factor lowering and thus the steep-slope switching (across for three decades with a minimum SS of 29 mV/decade at room temperature) for a monolayer MoS2 FET. Especially, a record-high sub-60-mV/decade current density (over 1 μA/μm) can be achieved compared to conventional steep-slope technologies such as tunneling FETs or negative capacitance FETs using 2D or 3D channel materials. Our work demonstrates the potential of a 2D Dirac-source cold electron transistor as a steep-slope transistor concept for future energy-efficient nanoelectronics.