Behavior of the thermal expansion coefficient of α-MoO3 as a function of the concentration of the Nd3+ ion

Alfonso, J. E.; Garzón, Rafael López; Moreno, Luis

doi:10.1016/j.physb.2012.06.034

Cited by 13 publications

(9 citation statements)

References 11 publications

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“…The determined parameters α a and α b are within three standard deviations of literature values (Table 1). α c , which was stated before to be insignificant, [21] is found to be negative (Table 1). Literature values for the thermal expansion of the unit cell volume V differ between 4.2 ⋅ 10 −5 K −1 and 7.5 ⋅ 10 −5 K −1 [22] .…”

Section: Resultsmentioning

confidence: 59%

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In situstudies on the industrial production process for molybdenum dioxide, MoO₂

Keilholz

Uhlenhut

Gabke

et al. 2023

Zeitschrift anorg allge chemie

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In the industrial production of molybdenum the reduction of molybdenum trioxide with hydrogen is a two‐step process. In order to get a deeper understanding of the chemistry involved, in situ studies were performed on the thermal behavior of molybdenum trioxide and the first reduction step to molybdenum dioxide. MoO3 shows a very strong anisotropy for thermal expansion (linear expansion coefficients α in 10−4 K−1: 1.32(4) for a, 5.5(1) for b, −0.246(5) for c). Upon heating in air, preferred orientation in XRPD patterns decreases and the color changes from grey to yellow, probably caused by decreasing oxygen vacancy concentration. The reduction of MoO3 by hydrogen was investigated via in situ X‐ray powder diffraction for varying heating rate, hydrogen flow and potassium content. The formation of the intermediate γ‐Mo4O11 shows a higher rate for increasing potassium content; it does not play a role whether potassium is present in the starting material MoO3 or in MoO2 formed in the reaction. The high‐temperature modification of K2MoO4 was found to crystallize in the α‐K2SO4 type (P63/mmc, a=6.3463(2) Å, c= 8.1331(2) Å). Heating up MoO3 in vacuum (1 Pa) with the same T,t protocol as above yields MoO2 even without the presence of hydrogen.

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Section: Resultsmentioning

confidence: 59%

“…Change in lattice parameters a, b and c and unit cell volume V of MoO 3 with temperature, expansion coefficients α and literature values α Lit . [21] x a b c V…”

Section: Tablementioning

confidence: 99%

In situstudies on the industrial production process for molybdenum dioxide, MoO₂

Keilholz

Uhlenhut

Gabke

et al. 2023

Zeitschrift anorg allge chemie

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“…Such crack is possible due to the difference of thermal expansion coefficient between PDMS and doping medium layer. [35][36][37][38][39] Then, the stamp doping is carried out by mechanical pressing as seen in the second step, where MoTe 2 FET is ready and the mechanical pressure on PDMS is as small as that for MoTe 2 vdW channel formation on the dielectric substrate (after exfoliation). Here, we expect a damage-free interface between doping media and channel as depicted in the third step figure.…”

Section: Resultsmentioning

confidence: 99%

Damage‐Free Charge Transfer Doping of 2D Transition Metal Dichalcogenide Channels by van der Waals Stamping of MoO₃ and LiF

et al. 2022

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To dope 2D semiconductor channels, charge‐transfer doping has generally been done by thermal deposition of inorganic or organic thin‐film layers on top of the 2D channel in bottom‐gate field‐effect transistors (FETs). The doping effects are reproducible in most cases. However, such thermal deposition will damage the surface of 2D channels due to the kinetic energy of depositing atoms, causing hysteresis or certain degradation. Here, a more desirable charge‐transfer doping process is suggested. A damage‐free charge‐transfer doping is conducted for 2D MoTe2 (or MoS2) channels using a polydimethylsiloxane stamp. MoO3 or LiF is initially deposited on the stamp as a doping medium. Hysteresis‐minimized transfer characteristics are achieved from stamp‐doped FETs, while other devices with direct thermal deposition‐doped channels show large hysteresis. The stamping method seems to induce a van der Waals‐like damage‐free interface between the channel and doping media. The stamp‐induced doping is also well applied for a MoTe2‐based complementary inverter because MoO3‐ and LiF‐doping by separate stamps effectively modifies two ambipolar MoTe2 channels to p‐ and n‐type, respectively.

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“…First, our demonstrated structures exhibit that 2D van der Waals polar crystal materials can be employed as thermal emitters. Specifically, the melting point of hBN and α-MoO 3 are reported to be 3000 K and 1653 K, [56,57] respectively, facilitating their use in higher temperature environment (e.g., thermophotovoltaic). Second, the emitters present ultrahigh quality-factor to thickness ratio (Qλ/t ≈ 3829/1608), which exceed (compared to film or metasurface emitters) or match (compared to gratings) the state-of-the-art thin narrowband thermal emitters (see Supporting Information Table S1 for detailed comparison).…”

Section: Discussionmentioning

confidence: 99%

Ultrathin High Quality‐Factor Planar Absorbers/Emitters Based on Uniaxial/Biaxial Anisotropic van der Waals Polar Crystals

Zhu

Cai

et al. 2021

Advanced Optical Materials

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Tailoring the absorption/emission through nanostructures from broadband to narrowband has attracted increasing attention due to the merits of high efficiency and compactness. However, most of the reported narrowband emitters require either complex fabrication process or thick coating of the suitable materials (~mm). In this paper, by exciting Berreman mode through a combination of Au mirrors and ultra‐thin layers of low‐loss uniaxial/biaxial anisotropic 2D van der Waals polar crystal hBN/α‐MoO3, a narrowband absorption/emission peak is realized in the mid‐infrared region. The measured quality‐factor of Berreman mode for hBN/Au and α‐MoO3/Au structure can reach up to 134 and 164, respectively. The deep subwavelength thickness (~nm) and bilayer architecture simplify the fabrication process. Furthermore, taking advantage of the in‐plane birefringence originating from α‐MoO3, the polarization of the absorbed/emitted radiation can be controlled through this planar configuration. Such ultrathin narrowband absorbers/emitters provide new opportunities for the advancements in thermal sources, infrared sensors, and thermophotovoltaic power generation systems.

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Behavior of the thermal expansion coefficient of α-MoO3 as a function of the concentration of the Nd3+ ion

Cited by 13 publications

References 11 publications

In situstudies on the industrial production process for molybdenum dioxide, MoO₂

In situstudies on the industrial production process for molybdenum dioxide, MoO₂

Damage‐Free Charge Transfer Doping of 2D Transition Metal Dichalcogenide Channels by van der Waals Stamping of MoO₃ and LiF

Ultrathin High Quality‐Factor Planar Absorbers/Emitters Based on Uniaxial/Biaxial Anisotropic van der Waals Polar Crystals

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Behavior of the thermal expansion coefficient of α-MoO3 as a function of the concentration of the Nd3+ ion

Cited by 13 publications

References 11 publications

In situstudies on the industrial production process for molybdenum dioxide, MoO2

In situstudies on the industrial production process for molybdenum dioxide, MoO2

Damage‐Free Charge Transfer Doping of 2D Transition Metal Dichalcogenide Channels by van der Waals Stamping of MoO3 and LiF

Ultrathin High Quality‐Factor Planar Absorbers/Emitters Based on Uniaxial/Biaxial Anisotropic van der Waals Polar Crystals

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Product

Resources

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In situstudies on the industrial production process for molybdenum dioxide, MoO₂

In situstudies on the industrial production process for molybdenum dioxide, MoO₂

Damage‐Free Charge Transfer Doping of 2D Transition Metal Dichalcogenide Channels by van der Waals Stamping of MoO₃ and LiF