Humidity‐Dependent Characteristics of Few‐Layer MoS₂ Field Effect Transistors

Abstract

reasons: i) few-layer MoS 2 has a smaller bandgap thus it can boost the current drive of FETs; ii) few-layer MoS 2 is less sensitive to ambience due to the smaller specific surface area; iii) few-layer MoS 2 is more immune to noise in air; iv) few-layer MoS 2 is more suitable for practical fabrication process to form large-area films. [19,20] Despite the above mentioned stability and feasibility, few-layer MoS 2 is highly sensitive to temperature and environmental gas, which seems to be limitations but actually offers new direction for the applications of few-layer MoS 2. [19,21-24] The effects of environmental gas on few-layer MoS 2 FET have been extensively studied in bottom gate configuration, paving the way for chemical sensors where changes of resistance and drain current are responsible for a successful detection. [23,24] Unfortunately, for these few-layer MoS 2 FETs, the humidity effects have not been systematically studied so far. Even though a few reports have discussed humidity-dependent transfer characteristics of MoS 2 FETs, these papers mainly focused on the single-or multilayer MoS 2 FETs. [25-28] Further, most of these works just demonstrated humidity sensing as proof-of-concept and failed to point out the subtleties of humidity-sensing performance and its relation to layered structures. To explore the intrinsic properties and improve the performance of few-layer MoS 2 FETs, thorough investigation of such humidity effects is required. Herein, tri-and six-layer MoS 2 films were prepared to fabricate FET-based humidity sensors and their characteristics, including on-state current, mobility, subthreshold slop, and hysteresis, were measured and discussed. Specially, the transfer characteristics in the linear regime (at low drain voltage, V DS) as a function of relative humidity (RH) in darkness were investigated to reveal the effect of humidity on the FETs. These results show that humidity significantly affects the electrical properties of few-layer MoS 2 FETs.

Recent progress on Schottky sensors based on two-dimensional transition metal dichalcogenides

“…2D TMDs are applied in gas detection extensively due to their excellent physicochemical and electrical properties. 112…”

“…2D TMDs are applied in gas detection extensively due to their excellent physicochemical and electrical properties. 112 Most of the gas sensors consisting of Schottky junctions between 2D TMDs and other materials can be regarded as a type of chemiresistive or chemical eld-effect transistors (chem-FETs), which operate according to the charge transfer process upon interaction with gas molecules or vapors by withdrawing electrons or accepting electrons. A high-performance gas sensor based on a Schottky junction between monolayer MoS 2 and Ti/ Au, which can work at room temperature, was developed (Fig.…”

A High‐Speed Photodetector Fabricated with Tungsten‐Doped MoS2 by Ion Implantation

“…Transition metal dichalcogenides (TMDs) have been studied in many fields due to their excellent properties, including tunable bandgap and broadband optical sensitivity. [1][2][3][4] As one of the most popular and widely researched 2D materials, MoS 2 has unique properties such as a high On-Off ratio, [5,6] suitable and tunable bandgap, [7][8][9] excellent stability, [10,11] etc., which makes it a strong competitor for next-generation nanoelectronic devices. [6,[12][13][14][15][16][17][18][19][20][21][22] MoS 2 photodetector.…”

Locally Thinned, Core–Shell Nanowire-Integrated Multi-gate MoS2 Transistors for Active Control of Extendable Logic

“…Therefore, new gate configurations, such as dual gates that combine bottom and top gates, , tri-gate structures, and the gate-all-around structures, , are designed to enhance the gate modulation ability. These FETs are supposed to be developed into many advanced electronic devices, such as logic units, , memory applications, , photodetectors, − sensors, , and so forth. Nevertheless, in most gate configurations mentioned above, insulators for gates are oxidized substrates, , deposited dielectric layers, or transferred layers, , and only one gate will ultimately appear on one side of the channel.…”