Two-dimensional transition metal nitrides offer intriguing
possibilities
for achieving novel electronic and mechanical functionality owing
to their distinctive and tunable bonding characteristics compared
to other 2D materials. We demonstrate here the enabling effects of
strong bonding on the morphology and functionality of 2D tungsten
nitrides. The employed bottom-up synthesis experienced a unique substrate
stabilization effect beyond van-der-Waals epitaxy that favored W5N6 over lower metal nitrides. Comprehensive structural
and electronic characterization reveals that monolayer W5N6 can be synthesized at large scale and shows semimetallic
behavior with an intriguing indirect band structure. Moreover, the
material exhibits exceptional resilience against mechanical damage
and chemical reactions. Leveraging these electronic properties and
robustness, we demonstrate the application of W5N6 as atomic-scale dry etch stops that allow the integration of high-performance
2D materials contacts. These findings highlight the potential of 2D
transition metal nitrides for realizing advanced electronic devices
and functional interfaces.