Highly conductive group VI transition metal dichalcogenide films by solution-processed deposition

A new soluble synthetic route was developed to fabricate thin films of layered structure transition metal dichalcogendies, MoS2 and WS2. High-quality thin films of the dichalcogenides were prepared using new soluble precursors, (CH3NH3)2MS4 (M = Mo, W). The precursors were dissolved in organic solvents and spun onto substrates via both single- and multistep spin coating procedures. The thin films were formed by the thermal decomposition of the coatings under inert atmosphere. Structural, electrical, optical absorption, thermal, and transport properties of the thin films were characterized. Surface morphology of the films was analyzed by atomic force microscopy and scanning electron microscopy. Highly conductive and textured n-type MoS2 films were obtained. The measured room temperature conductivity ∼50 Ω−1 cm−1 is substantially higher than the previously reported values. The n-type WS2 films were prepared for the first time using solution-processed deposition. WS2 displays a conductivity of ∼6.7 Ω−1 cm−1 at room temperature.

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Structure and Conductivity of Iodine-Doped C60 Thin Films

MRS Proceedings ◽

10.1557/proc-359-443 ◽

1994 ◽

Vol 359 ◽

Cited By ~ 1

Author(s):

Jun Chen ◽

Haiyan Zhang ◽

Baoqiong Chen ◽

Shaoqi Peng ◽

Ning Ke ◽

...

Keyword(s):

Thin Films ◽

Electrical Conductivity ◽

Room Temperature ◽

Conductivity Measurements ◽

X Ray Diffraction ◽

Temperature Conductivity ◽

Room Temperature Conductivity ◽

X Ray ◽

Thermally Activated ◽

Order Of Magnitude

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.

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Organic Based Magnetic Thin Films by Low Temperature CVD

MRS Proceedings ◽

10.1557/proc-871-i7.3 ◽

2005 ◽

Vol 871 ◽

Cited By ~ 1

Author(s):

Ruth Shima Edelstein ◽

Jung-Woo Yoo ◽

N. P. Raju ◽

Jeremy D. Bergeson ◽

Konstantin I. Pokhodnya ◽

...

Keyword(s):

Thin Films ◽

Room Temperature ◽

Spin Valve ◽

Chemical Vapor ◽

Magnetic Ordering ◽

Magnetic Thin Films ◽

Temperature Conductivity ◽

Room Temperature Conductivity ◽

Paramagnetic Material ◽

Vanadium Tetracyanoethylene

AbstractWe describe how the composition of an organic - based magnet can be controlled by varying the Chemical Vapor Deposition (CVD) conditions. A study was conducted for the Co2(CO)8/ TCNE system to form cobalt tetracyanoethylene [Co(TCNE)x, x∼2, a paramagnetic material], and for the V(CO)6/ TCNEx system to form vanadium tetracyanoethylene [V(TCNE)x, x∼2, a ferrimagnetic material]. Thin V(TCNE)x, x∼2 films (∼0.05-0.5 μm) with room temperature conductivity of 10-4<σRT<10-3S/cm and magnetic ordering temperature Tc of up to ∼400K were deposited. The V(TCNE)x, x∼2 thin films have the potential for incorporation in a spin-valve device as one of the magnetic contacts, and are promising candidates to form optically controlled magnetic-based structures.

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a-Si:N:H prepared by reactive evaporation in ammonia vapour

Canadian Journal of Physics ◽

10.1139/p87-165 ◽

1987 ◽

Vol 65 (8) ◽

pp. 1020-1022

Author(s):

R. D. Audas ◽

D. E. Brodie

Keyword(s):

Thin Films ◽

Room Temperature ◽

Activation Energies ◽

High Activation ◽

Temperature Conductivity ◽

Room Temperature Conductivity ◽

Reactive Evaporation ◽

Ammonia Vapour ◽

Optical Bandgaps ◽

P Type

The reactive evaporation of Si in an ammonia ambient has been used to produce a-Si:N:H thin films. These films are "intrinsic-like" with low room-temperature conductivities (<10−12 S∙cm−1), high activation energies (0.9 eV), and high optical bandgaps (1.9 eV). Films prepared in this manner have been doped using co-evaporation of antimony (n type) and indium (p type). The addition of 2 at.% indium or antimony results in an increase in the room-temperature conductivity by eight and six orders of magnitude respectively. The undoped and doped samples are photoconductive when illuminated with a quartz-halogen source.

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Room-temperature synthesized copper iodide thin film as degenerate p-type transparent conductor with a boosted figure of merit

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1613643113 ◽

2016 ◽

Vol 113 (46) ◽

pp. 12929-12933 ◽

Cited By ~ 86

Author(s):

Chang Yang ◽

Max Kneiβ ◽

Michael Lorenz ◽

Marius Grundmann

Keyword(s):

Thin Films ◽

Figure Of Merit ◽

Room Temperature ◽

Visible Spectral Range ◽

Transparent Conductors ◽

Transparent Conductor ◽

Temperature Dependent ◽

Temperature Conductivity ◽

Room Temperature Conductivity ◽

P Type

A degenerate p-type conduction of cuprous iodide (CuI) thin films is achieved at the iodine-rich growth condition, allowing for the record high room-temperature conductivity of ∼156 S/cm for as-deposited CuI and ∼283 S/cm for I-doped CuI. At the same time, the films appear clear and exhibit a high transmission of 60–85% in the visible spectral range. The realization of such simultaneously high conductivity and transparency boosts the figure of merit of a p-type TC: its value jumps from ∼200 to ∼17,000 MΩ−1. Polycrystalline CuI thin films were deposited at room temperature by reactive sputtering. Their electrical and optical properties are examined relative to other p-type transparent conductors. The transport properties of CuI thin films were investigated by temperature-dependent conductivity measurements, which reveal a semiconductor–metal transition depending on the iodine/argon ratio in the sputtering gas.

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Old Donors for New Molecular Conductors: Combining TMTSF and BEDT-TTF with Anionic (TaF6)1−x/(PF6)x Alloys

Crystals ◽

10.3390/cryst11040386 ◽

2021 ◽

Vol 11 (4) ◽

pp. 386

Author(s):

Magali Allain ◽

Cécile Mézière ◽

Pascale Auban-Senzier ◽

Narcis Avarvari

Keyword(s):

Single Crystal ◽

Room Temperature ◽

Density Wave ◽

Spin Density Wave ◽

Orthorhombic Phase ◽

Molecular Conductors ◽

Bechgaard Salts ◽

Temperature Conductivity ◽

Room Temperature Conductivity ◽

Resistivity Measurements

Tetramethyl-tetraselenafulvalene (TMTSF) and bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) are flagship precursors in the field of molecular (super)conductors. The electrocrystallization of these donors in the presence of (n-Bu4N)TaF6 or mixtures of (n-Bu4N)TaF6 and (n-Bu4N)PF6 provided Bechgaard salts formulated as (TMTSF)2(TaF6)0.84(PF6)0.16, (TMTSF)2(TaF6)0.56(PF6)0.44, (TMTSF)2(TaF6)0.44(PF6)0.56 and (TMTSF)2(TaF6)0.12(PF6)0.88, together with the monoclinic and orthorhombic phases δm-(BEDT-TTF)2(TaF6)0.94(PF6)0.06 and δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57, respectively. The use of BEDT-TTF and a mixture of (n-Bu4N)TaF6/TaF5 afforded the 1:1 phase (BEDT-TTF)2(TaF6)2·CH2Cl2. The precise Ta/P ratio in the alloys has been determined by an accurate single crystal X-ray data analysis and was corroborated with solution 19F NMR measurements. In the previously unknown crystalline phase (BEDT-TTF)2(TaF6)2·CH2Cl2 the donors organize in dimers interacting laterally yet no organic-inorganic segregation is observed. Single crystal resistivity measurements on the TMTSF based materials show typical behavior of the Bechgaard phases with room temperature conductivity σ ≈ 100 S/cm and localization below 12 K indicative of a spin density wave transition. The orthorhombic phase δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57 is semiconducting with the room temperature conductivity estimated to be σ ≈ 0.16–0.5 S/cm while the compound (BEDT-TTF)2(TaF6)2·CH2Cl2 is also a semiconductor, yet with a much lower room temperature conductivity value of 0.001 to 0.0025 S/cm, in agreement with the +1 oxidation state and strong dimerization of the donors.

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Synthesis and Characterization of Lithium-Ion Conductive LATP-LaPO4 Composites Using La2O3 Nano-Powder

Materials ◽

10.3390/ma14133502 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3502

Author(s):

Fangzhou Song ◽

Masayoshi Uematsu ◽

Takeshi Yabutsuka ◽

Takeshi Yao ◽

Shigeomi Takai

Keyword(s):

Room Temperature ◽

Conduction Mechanism ◽

Lithium Ion ◽

X Ray Diffraction ◽

Temperature Conductivity ◽

Room Temperature Conductivity ◽

X Ray ◽

Nano Powder ◽

Powder Addition

LATP-based composite electrolytes were prepared by sintering the mixtures of LATP precursor and La2O3 nano-powder. Powder X-ray diffraction and scanning electron microscopy suggest that La2O3 can react with LATP during sintering to form fine LaPO4 particles that are dispersed in the LATP matrix. The room temperature conductivity initially increases with La2O3 nano-powder addition showing the maximum of 0.69 mS∙cm−1 at 6 wt.%, above which, conductivity decreases with the introduction of La2O3. The activation energy of conductivity is not largely varied with the La2O3 content, suggesting that the conduction mechanism is essentially preserved despite LaPO4 dispersion. In comparison with the previously reported LATP-LLTO system, although some unidentified impurity slightly reduces the conductivity maximum, the fine dispersion of LaPO4 particles can be achieved in the LATP–La2O3 system.

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