Local Fermi Level Engineering in 2D-MoS2 Realized via Microcontact Printing of Self-Assembled Monolayers for Next-Generation Electronics

Silicon-based technology is approaching scalability limits due to severe short-channel effects arising from its intrinsic bulk properties. In contrast, two-dimensional (2D) transition metal dichalcogenides (TMDCs) exhibit remarkable resilience to these effects because of their atomic-scale thickness, positioning them as promising candidates for next-generation optical and electronic devices. However, realizing 2D material-based technology still requires the development of local p- and n-type doping methods essential for complementary circuits. Self-assembled monolayers (SAMs) have shown the ability to locally engineer electronic energy levels in 2D TMDCs to address this challenge. In this study, we demonstrate local engineering of electronic energy levels on micrometer scale in semiconducting single-layer (1L) MoS2 by patterning the supporting substrate with functional SAMs via microcontact printing (µCP). Three SAMs were selected: two with large opposing dipole moments and one non-dipolar reference. Their impact on surface properties particularly the work function and on optoelectronic properties of 1L-MoS2 was investigated via Kelvin probe microscopy and photoluminescence (PL) mapping. Significant shifts in work function and PL were observed. FETs fabricated on locally patterned substrates enabled direct comparison, confirming that threshold voltage shifts up to 80 V and ON-current increases by two orders of magnitude arise solely from SAM polarity. This work demonstrates that µCP and the electrostatic doping capabilities of dipolar SAMs offer a straight forward and scalable approach to locally engineering 1L-MoS2 energy levels.