Tuning Transport and Chemical Sensitivity via Niobium Doping of Synthetic MoS 2

Beyond the intrinsic properties of 2D materials, another advantage is the tunability that follows from their low dimensionality. Here, large‐area Nb‐doped MoS 2 monolayer films deposited by metal organic chemical vapor deposition that can function as electrical contacts or chemical sensors are demonstrated. Compared to pristine MoS 2 , Nb‐doped MoS 2 exhibits a relatively faster growth rate and quenched PL due to formation of mid‐gap energy bands. When the Nb concentration reaches 5 at%, doped MoS 2 shows clear p‐type characteristics, evident by a 1.7 eV shift of the Fermi level toward the valence band maximum. Doping also impacts transport at the metal/MoS 2 interface, demonstrated by Pt–Ir metallization that is Schottky‐limited when in contact with undoped MoS 2 but Ohmic on Nb‐MoS 2 . Moreover, a 50 × improved signal‐to‐noise ratio is demonstrated in sensing triethylamine compared to undoped MoS 2 , with < 15 parts‐per‐billion detection limit.