A Facile and Effective Method for Patching Sulfur Vacancies of WS₂ via Nitrogen Plasma Treatment

Abstract

Although transition metal dichalcogenides (TMDs) are attractive for the next‐generation nanoelectronic era due to their unique optoelectronic and electronic properties, carrier scattering during the transmission of electronic devices, and the distinct contact barrier between the metal and the semiconductors, which is caused by inevitable defects in TMDs, remain formidable challenges. To address these issues, a facile, effective, and universal patching defect approach that uses a nitrogen plasma doping protocol is developed, via which the intrinsic vacancies are repaired effectively. To reveal sulfur vacancies and the nature of the nitrogen doping effects, a high‐resolution spherical aberration corrected scanning transmission electron microscopy is used, which confirms the N atoms doping in sulfur vacancies. In this study, a typical TMD material, namely tungsten disulfide, is employed to fabricate field‐effect transistors (FETs) as a preliminary paradigm to demonstrate the patching defects method. This doping method endows FETs with high electrical performance and excellent contact interface properties. As a result, an electron mobility of up to 184.2 cm2 V−1 s−1 and a threshold voltage of as low as 3.8 V are realized. This study provides a valuable approach to improve the performance of electronic devices that are based on TMDs in practical electronic applications.

Defect Engineering in 2D Materials: Precise Manipulation and Improved Functionalities

“…As a result, the mobility of electrons in MoS 2 is increased by about 48 times. Similarly, the sulfur vacancies of WS 2 can be filled by nitrogen atoms after N 2 plasma treatment, which is confirmed by STEM [75]. The density of SVs is reduced, leading to an improved mobility to 184.2 cm 2 V −1 s −1 (Figure 4(c)).…”

“…(c) Transfer characteristic of WS 2 with/without N 2 plasma treatment (1) and the schematic diagram of P substitutions in WS 2 (2). Reproduced from [75].…”

Giant‐Enhanced SnS2 Photodetectors with Broadband Response through Oxygen Plasma Treatment

“…During the O 2 plasma treatment, the surface of the SnS 2 flake is etched, and oxygen atoms are simultaneously implanted. [ 33,34 ] As a result, the constructed O 2 ‐plasma‐treated SnS 2 ‐based device demonstrates a significant improvement in broadband photosensing from ultraviolet to cover the entire visible light span (300–750 nm). Particularly under 350 nm illumination, the O 2 ‐plasma‐treated SnS 2 photodetector exhibits an enhanced photoresponsivity from 385 to 860 A W −1 , external quantum efficiency from 1.3 × 10 5 % to 3.1 × 10 5 %, specific detectivity from 4.5 × 10 9 to 1.1 × 10 10 Jones, as well as improved photo‐switching response from 12 and 17 s to 0.7 and 0.6 s for rising (τ r ) and decay (τ d ) time, respectively.…”

Plasma Treatment: a Novel Approach to Improve the Photoelectroactivity of Sb2S3 Thin Films to Water Splitting

“…It is very likelihood that the bombardment of these reactive species such as nitrogen ions onto the Sb 2 S 3 film resulted in their incorporation as S−N bonds on the film's surface. The introduction of nitrogen specie upon materials’ surface by nitrogen plasma treatment was also reported for other chalcogenides as well as polymers . Albeit the mechanism behind the S−N bond formation by the nitrogen plasma interaction is still not well understood, we believe that the steps involved are the cleavage of the sulfur bonds by the nitrogen ion collisions and the subsequent S−N bond formation as similarly reported for other systems .…”