Rhenium-doped MoS2 films

Hallam, Toby; Monaghan, Scott; Gity, Farzan; Ansari, Lida; Schmidt, Michael; Downing, Clive; Cullen, Conor P.; Nicolosi, Valeria; Hurley, Paul K.; Duesberg, Georg S.

doi:10.1063/1.4995220

Cited by 45 publications

(43 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…No Raman changes were observed, and in particular no sign of ReS2 formation. TEM showed Re in Mo sites, and a small increase in the in-plane lattice spacing, while scanning tunneling microscopy (STM) suggested Mo substitution within grains and intercalation at grain boundaries [177]. Another STM study also showed Mo substitution by Re [178].…”

Section: Structure Of Doped Mos2mentioning

confidence: 98%

Solid Lubrication with MoS2: A Review

et al. 2019

View full text Add to dashboard Cite

Molybdenum disulfide (MoS2) is one of the most broadly utilized solid lubricants with a wide range of applications, including but not limited to those in the aerospace/space industry. Here we present a focused review of solid lubrication with MoS2 by highlighting its structure, synthesis, applications and the fundamental mechanisms underlying its lubricative properties, together with a discussion of their environmental and temperature dependence. An effort is made to cover the main theoretical and experimental studies that constitute milestones in our scientific understanding. The review also includes an extensive overview of the structure and tribological properties of doped MoS2, followed by a discussion of potential future research directions.MoS2 belongs to the family of layered two-dimensional transitional metal dichalcogenides (TMDs). Like graphite and hexagonal boron nitride, its crystal structure consists of covalently bonded sheets, which form stacks that are held together only by weak Van der Waals interactions [16]. It occurs naturally as the mineral molybdenite, an important Mo ore. Due to the strong bonding inplane and weak bonding out-of-plane, mechanical and other properties are highly anisotropic [17], and the stacks can be easily sheared. Single-layer or few-layer (i.e. 2D) MoS2 (analogous to graphene) can be produced and studied individually [18].MoS2 has several different possible structures (polytypes), depending on the bonding within the sheets and the stacks of the sheets. While graphite has a single plane of atoms per sheet, in MoS2 each sheet consists a plane of Mo atoms sandwiched between two planes of S atoms. The single-sheet structure can feature trigonal prismatic coordination around Mo, which is the semiconducting 1H ("hexagonal") structure, or octahedral bonding, which is the metallic 1T ("trigonal") phase. 1H and the ideal 1T each have 3 atoms (MoS2) per unit cell ( Figure 1); however, theoretical calculations with density-functional theory (DFT)[19] and X-ray diffraction (XRD) experiments [20] have shown that in fact 1T is unstable with respect to distortions. The most commonly reported structure is a 3× 3 distortion that triples the unit cell, known as the 1T′ phase [21].Each single-sheet structure can be stacked into a crystal where the next sheet is exactly above the preceding one (AA stacking), producing the 1H, 1T, and 1T′ polytypes. The naturally occurring polytypes in molybdenite, however, are only based on the 1H sheet, and show more complicated stacking [9]. The more common is the 2H structure with 2 sheets per cell in AB stacking, where an S atom in one layer is above an Mo atom in the layer below [22,23]. The less common 3R ("rhombohedral") structure has 3 sheets per cell with ABC stacking [22,24]. These structures are shown in Figure 1. Mo-S bond lengths are around 2.4 Å for all polytypes [25]. DFT calculations show only very small energy differences between the 2H and 3R phases [25]. This insensitivity to stacking, and the low surface energy for 2H-MoS2 of 47 mJ/m 2 =...

show abstract

Section: Structure Of Doped Mos2mentioning

confidence: 98%

Solid Lubrication with MoS2: A Review

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Hallam et al also demonstrated the scalable synthesis of Re-doped MoS 2 films with electron concentrations in the range of 5 × 10 17 to 9 × 10 17 cm −3 as determined via Hall effect measurements and supported by DFT calculations. In their approach, the authors used "thermally-assisted conversion" (TAC), similar to the method used by Lasker et al to synthesize Nb-doped p-type MoS 2 films [405], to convert interleaved Mo-Re films into Re-doped MoS 2 via high-temperature sulfurization [411]. However, the electron mobility of their Re-doped MoS 2 films was low, ranging between 0.1 to 0.7 cm 2 /V-s, implying the presence of various carrier scattering sources (including scattering from the incorporated Re dopant atoms).…”

Section: Electron Doping By Cation Substitutionmentioning

confidence: 99%

Progress in Contact, Doping and Mobility Engineering of MoS2: An Atomically Thin 2D Semiconductor

et al. 2018

View full text Add to dashboard Cite

Atomically thin molybdenum disulfide (MoS2), a member of the transition metal dichalcogenide (TMDC) family, has emerged as the prototypical two-dimensional (2D) semiconductor with a multitude of interesting properties and promising device applications spanning all realms of electronics and optoelectronics. While possessing inherent advantages over conventional bulk semiconducting materials (such as Si, Ge and III-Vs) in terms of enabling ultra-short channel and, thus, energy efficient field-effect transistors (FETs), the mechanically flexible and transparent nature of MoS2 makes it even more attractive for use in ubiquitous flexible and transparent electronic systems. However, before the fascinating properties of MoS2 can be effectively harnessed and put to good use in practical and commercial applications, several important technological roadblocks pertaining to its contact, doping and mobility (µ) engineering must be overcome. This paper reviews the important technologically relevant properties of semiconducting 2D TMDCs followed by a discussion of the performance projections of, and the major engineering challenges that confront, 2D MoS2-based devices. Finally, this review provides a comprehensive overview of the various engineering solutions employed, thus far, to address the all-important issues of contact resistance (RC), controllable and area-selective doping, and charge carrier mobility enhancement in these devices. Several key experimental and theoretical results are cited to supplement the discussions and provide further insight.

show abstract

“… 27 , 36 In most cases, substitutionally doped MoS 2 is synthesized by high-temperature sulfurization (900 °C is not uncommon) of an alloy or a nanolaminate of metallic Mo and the pure dopant. 37 Substitutional doping of TMDs with, for example, Nb, 27 Er, 38 C, 28 Ti, 39 Zn, 15 and Cl, 36 has already been reported using this strategy, resulting in mainly n -type doping, in a few instances,in p -type doping, and inmost cases this approach exhibited limited control over the dopant level.…”

Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition of Al-Doped MoS₂: Synthesizing a p-type 2D Semiconductor with Tunable Carrier Density

Vandalon

Verheijen

Kessels

et al. 2020

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

Extrinsically doped two-dimensional (2D) semiconductors are essential for the fabrication of high-performance nanoelectronics among many other applications. Herein, we present a facile synthesis method for Al-doped MoS 2 via plasma-enhanced atomic layer deposition (ALD), resulting in a particularly sought-after p -type 2D material. Precise and accurate control over the carrier concentration was achieved over a wide range (10 17 up to 10 21 cm –3 ) while retaining good crystallinity, mobility, and stoichiometry. This ALD-based approach also affords excellent control over the doping profile, as demonstrated by a combined transmission electron microscopy and energy-dispersive X-ray spectroscopy study. Sharp transitions in the Al concentration were realized and both doped and undoped materials had the characteristic 2D-layered nature. The fine control over the doping concentration, combined with the conformality and uniformity, and subnanometer thickness control inherent to ALD should ensure compatibility with large-scale fabrication. This makes Al:MoS 2 ALD of interest not only for nanoelectronics but also for photovoltaics and transition-metal dichalcogenide-based catalysts.

show abstract

Rhenium-doped MoS2 films

Cited by 45 publications

References 35 publications

Solid Lubrication with MoS2: A Review

Solid Lubrication with MoS2: A Review

Progress in Contact, Doping and Mobility Engineering of MoS2: An Atomically Thin 2D Semiconductor

Atomic Layer Deposition of Al-Doped MoS₂: Synthesizing a p-type 2D Semiconductor with Tunable Carrier Density

Contact Info

Product

Resources

About

Rhenium-doped MoS2 films

Cited by 45 publications

References 35 publications

Solid Lubrication with MoS2: A Review

Solid Lubrication with MoS2: A Review

Progress in Contact, Doping and Mobility Engineering of MoS2: An Atomically Thin 2D Semiconductor

Atomic Layer Deposition of Al-Doped MoS2: Synthesizing a p-type 2D Semiconductor with Tunable Carrier Density

Contact Info

Product

Resources

About

Atomic Layer Deposition of Al-Doped MoS₂: Synthesizing a p-type 2D Semiconductor with Tunable Carrier Density