Metal Semiconductor Field-Effect Transistor with MoS₂/Conducting NiO_x van der Waals Schottky Interface for Intrinsic High Mobility and Photoswitching Speed

Abstract

Molybdenum disulfide (MoS2) nanosheet, one of two-dimensional (2D) semiconductors, has recently been regarded as a promising material to break through the limit of present semiconductors. With an apparent energy band gap, it certainly provides a high carrier mobility, superior subthreshold swing, and ON/OFF ratio in field-effect transistors (FETs). However, its potential in carrier mobility has still been depreciated since the field-effect mobilities have only been measured from metal-insulator-semiconductor (MIS) FETs, where the transport behavior of conducting carriers located at the insulator/MoS2 interface is unavoidably interfered by the interface traps and gate voltage. Moreover, thin MoS2 MISFETs have always shown large hysteresis with unpredictable negative threshold voltages. Here, we for the first time report MoS2-based metal semiconductor field-effect transistors (MESFETs) using NiOx Schottky electrode which makes van der Waals interface with MoS2. We thus expect that the maximum mobilities or carrier transport behavior of the Schottky devices may hardly be interfered by interface traps or an on-state gate field. Our MESFETs with a few and ∼10 layer MoS2 demonstrate intrinsic-like high mobilities of 500-1200 cm(2)/(V s) at a certain low threshold voltage between -1 and -2 V without much hysteresis. Moreover, they work as a high speed and highly sensitive phototransistor with 2 ms switching and ∼5000 A/W, respectively, supporting their high intrinsic mobility results.

Booming Development of Group IV–VI Semiconductors: Fresh Blood of 2D Family

“…The drain–source current is controlled by the gate voltage on the dielectric layer. High carrier mobility, high switching ratio and low subthreshold swing means high performance FET, which depends on the metal contacts,247 channel materials (thickness,248, 249 doping,192, 250, 251, 252, 253, 254 heterostructures200, 208), dielectric materials (back‐gate,86, 255 top‐gate,256 liquid gate257), and so forth. 2D GIVMCs based FETs have demonstrated exciting performance.…”

Top‐Down Integration of Molybdenum Disulfide Transistors with Wafer‐Scale Uniformity and Layer Controllability

“…High performance field effect transistors (FETs) based on exfoliated TMDCs have been fabricated and found to exhibit large On/Off current ratio (over 10 7 ), high elec tron mobility (exceeding 200 cm 2 V −1 s −1 ) and small cutoff current (less than 1 pA). [8,9] …”

“…High performance field effect transistors (FETs) based on exfoliated TMDCs have been fabricated and found to exhibit large On/Off current ratio (over 10 7 ), high elec tron mobility (exceeding 200 cm 2 V −1 s −1 ) and small cutoff current (less than 1 pA). [8,9] Nevertheless, current research on TMDCs is largely limited by the relatively small lateral size of exfoliated flakes and instable transfer techniques of large chemical vapor deposition (CVD) samples. There is an urgent need to develop a stable and efficient technique to DOI: 10.1002/smll.201603157 2 …”

Nucleic acid-functionalized transition metal nanosheets for biosensing applications

“…For example, layered MoS 2 consists of a sandwich structure of Mo atoms between two layers of S atoms, exhibiting strong in-plane covalent bonding and weak out-of-plane interaction, therefore enabling exfoliation from bulk 3D materials into 2D nanosheets (Ataca and Ciraci 2011; Brent et al 2015; Huang et al 2013b; Leonard and Talin 2011; Schwierz 2011). Single- or few-layer nanosheets present many attractive properties over their bulk counterparts and, as such, cater to wide applications in nanoelectronics (Lee et al 2015; Radisavljevic et al 2011a; Wu et al 2014; Yin et al 2012), catalysis (Chianelli et al 2006; Gao et al 2015; Huang et al 2013a), energy harvesting (Jaramillo et al 2007; Sun et al 2014a) and biomedicine (Chen et al 2015b; Cheng et al 2014). On the other hand, TMOs are composed of oxygen atoms bound to transition metals.…”