Tuning Transport and Chemical Sensitivity via Niobium Doping of Synthetic MoS2. Issue 18 (5th August 2020)

• Record Type: Journal Article
• Authors: Zhang, Kehao; Deng, Donna D.; Zheng, Boyang; Wang, Yuanxi; Perkins, F. Keith; Briggs, Natalie C.; Crespi, Vincent H.; Robinson, Joshua A.
• Is Part Of: Advanced materials interfaces. Volume 7:Issue 18(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-05
• Subjects: 2D materials -- MoS 2 -- niobium doping -- sensing; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202000856
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Beyond the intrinsic properties of 2D materials, another advantage is the tunability that follows from their low dimensionality. Here, large‐area Nb‐doped MoS2 monolayer films deposited by metal organic chemical vapor deposition that can function as electrical contacts or chemical sensors are demonstrated. Compared to pristine MoS2, Nb‐doped MoS2 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 MoS2 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/MoS2 interface, demonstrated by Pt–Ir metallization that is Schottky‐limited when in contact with undoped MoS2 but Ohmic on Nb‐MoS2 . Moreover, a 50 × improved signal‐to‐noise ratio is demonstrated in sensing triethylamine compared to undoped MoS2, with < 15 parts‐per‐billion detection limit. Abstract : This article demonstrates the uniform in situ Nb doping on MoS2 in centimeter scale. Nb‐MoS2 is p‐type with ≈5.6% Nb concentration (Nb/Mo). This doping system activates the lower detection limits (15 ppb) to triethylamine. Meanwhile, p‐type MoS2 benefits the metal contact performance, evident by Ohmic like I – V curve when contacting Pt/Ir alloy.