UC Santa Barbara

Abstract: Two-dimensional (2D) semiconducting materials, in particular transition-metal dichalcogenides, have emerged as the preferred channel materials for sub-5 nm field-effect transistors (FETs). However, the lack of practical doping techniques for these materials poses a significant challenge to designing complementary logic gates containing both n- and p-type FETs. Although electrical tuning of the polarity of 2D-FETs can potentially circumvent this problem, such devices suffer from the lack of balanced n- and p-mode transistor performance, forming one of the most enigmatic challenges of the reconfigurable 2D-FET technology. Here we provide a solution to this dilemma by judicious use of van der Waals (vdW) materials consisting of conductors, dielectrics and semiconductors forming a 50 nm thin quantum engineered strata that can guarantee a purely vdW-type interlayer interaction, which faithfully preserves the mid-gap contact design and thereby achieves an intrinsically mode-balanced and fully reconfigurable all-2D logic gate. The intrinsically mode-balanced gate eliminates the need for transistor sizing and allows post-fabrication reconfigurability to the transistor operation mode, simultaneously allowing an ultra-compact footprint and increased circuit functionality, which can be potentially exploited to build more area-efficient and low-cost integrated electronics for the internet of things (IoT) paradigm.