MoO3 films grown on polycrystalline Cu: Morphological, structural, and electronic properties

Macis, Salvatore; Aramo, C.; Bonavolontà, C.; Cibin, Giannantonio; D׳Elia, A.; Davoli, I.; Lucia, Mario de; Lucci, M.; Lupi, S.; Miliucci, M.; Notargiacomo, A.; Ottaviani, Carlo; Scarselli, Manuela; Scifo, J.; Valentino, M.; Padova, Paola De; Marcelli, A.

doi:10.1116/1.5078794

Cited by 16 publications

(19 citation statements)

References 32 publications

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“…Actually, these films are complex nanophase systems where molybdenum may exist in several oxidation states: Mo 4+ , Mo 5+ , and Mo 6+ , and whose valence and structure also change with the temperature and the annealing treatments. To enhance the order of the existing phases, different thermal treatments could be performed [25].…”

Section: Resultsmentioning

confidence: 99%

“…MoO3 coated on copper by physical vapor deposition in vacuum without thermal annealing mainly grows as a disordered film [25,26]. To characterize the quality of these films deposed by PLD [27][28][29], we also performed X-ray fluorescence (XRF) experiments at the XlabF RXR facility of LNF, based on a confocal set that was characterized by probing a spherical object of ~80 µm diameter [21].…”

Section: Evaluation Of Moo3 Films Thicknessesmentioning

confidence: 99%

“…As an example, MoO 3 films are multiphase metallic systems with a non-negligible contribution of disordered oxide phases: transparent and insulating phases such as MoO 3 or metallic phases such as MoO 2 , both of high-interest also for technological applications. Different chemical and structural factors may affect the properties of MoO 3 films and, in particular, the work function [1,25]. We have already studied thin films of MoO 3 growth by physical vapor deposition in vacuum [25,26], here we will describe the molybdenum oxide (MoO 3 ) films deposited by pulsed-laser deposition (PLD) and their preliminary mechanical characterization.…”

Section: Introductionmentioning

confidence: 99%

“…Different chemical and structural factors may affect the properties of MoO 3 films and, in particular, the work function [1,25]. We have already studied thin films of MoO 3 growth by physical vapor deposition in vacuum [25,26], here we will describe the molybdenum oxide (MoO 3 ) films deposited by pulsed-laser deposition (PLD) and their preliminary mechanical characterization.…”

Section: Introductionmentioning

confidence: 99%

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Molybdenum Oxides Coatings for High Demanding Accelerator Components

et al. 2019

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Large electric gradients are required for a variety of new applications, notably including the extreme high brightness electron sources for X-ray free electron lasers (FELs), radio-frequency (RF) photo-injectors, industrial and medical accelerators, and linear accelerators for particle physics colliders. In the framework of the INFN-LNF, SLAC (USA), KEK (Japan), UCLA (Los Angeles) collaboration, the Frascati National Laboratories (LNF) are involved in the modelling, development, and testing of RF structures devoted to particles acceleration by high gradient electric fields of particles through metal devices. In order to improve the maximum sustainable gradients in normal-conducting RF-accelerating structures, both the RF breakdown and dark current should be minimized. To this purpose, studying new materials as well as manufacturing techniques are mandatory to identify better solutions to such extremely requested applications. In this contribution, we discuss the possibility of using a dedicated coating on a solid copper sample (and other metals) with a relatively thick film to improve and optimize breakdown performances and to minimize the dark current. We present here the first characterization of MoO3 films deposited on copper by pulsed-laser deposition (PLD).

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Section: Resultsmentioning

confidence: 99%

Section: Evaluation Of Moo3 Films Thicknessesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molybdenum Oxides Coatings for High Demanding Accelerator Components

et al. 2019

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“…High-intensity THz radiation is also useful for producing a high-gradient electric field for particle acceleration [26]. The investigation of the behaviour of metallic cavities [27] under the application of a high-intensity THz field represents an important issue in the development of compact accelerators [22] and to test protective coatings designed to reduce the damaging processes [28,29]. Copper, in particular, represents a strategic material to study under high-gradient electric fields, due to its extensive use in many accelerating components subjected to high electric fields.…”

Section: Introductionmentioning

confidence: 99%

Angular Dependence of Copper Surface Damage Induced by an Intense Coherent THz Radiation Beam

et al. 2020

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In this work, we show the damage induced by an intense coherent terahertz (THz) beam on copper surfaces. The metallic surface was irradiated by multiple picosecond THz pulses generated by the Free Electron Laser (FEL) at the ISIR facility of the Osaka University, reaching an electric field on the sample surface up to ~4 GV/m. No damage occurs at normal incidence, while images and spectroscopic analysis of the surface point out a clear dependence of the damage on the incidence angle, the electric field intensity, and polarization of the pulsed THz radiation. Ab initio analysis shows that the damage at high incidence angles could be related to the increase of the absorbance, i.e., to the increase of the temperature around or above 1000 °C. The experimental approach we introduced with multiple fast irradiations represents a new powerful technique useful to test, in a reproducible way, the damage induced by an intense electric gradient on copper and other metallic surfaces in view of future THz-based compact particle accelerators.

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Metallic Interface Induced Ionic Redistribution within Amorphous MoO₃ Films

Paparoni

Mijiti

Minicucci

et al. 2022

Adv Materials Inter

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molybdenum oxides recently attracted the attention, due to the peculiar features of this class of oxide, originating from the interplay between the large variety of lattice configuration and the multiple valence states of Mo. [5][6][7] Even though MoO 3 is a high-k dielectric insulator, its electronic structure can be adjusted by modifying the oxygen substoichiometry (MoO 3−x ), introducing electronic gap states that modifies the oxide's electrical conductivity. [8,9] The stoichiometric MoO 3 is an n-type material with an equilibrium concentration of defects (mainly oxygen vacancies), which cause the formation of Mo 5+ , that partially occupies Mo 4d band creating gap states. These states play as n-type dopant, push the MoO 3 Fermi level closer to the conduction band. A continuous removal of oxygen may reduce MoO 3 to MoO 2 , the lowest stable molybdenum oxide, which contains Mo 4+ cations, that give rise to a partially filled 4d band resulting in semi-metallic states.The consequent electronic properties of the vacancy formation have shown applicability across a number of technological fields, including promising electrochromic, battery cathode material, and gas sensors. [10,11] It has also been shown thatThe phase evolution and ionic redistribution in amorphous MoO 3 films, deposited on metallic aluminium (Al) and copper (Cu) substrates and subjected to distinct thermal treatments, are systematically investigated in this work. It is shown that the metallic interface significantly modifies the formation and dynamics of oxygen vacancies within the resulted structure, reducing the oxygen content of the MoO 3 up to x < 2.94. The concentration of the oxygen vacancies can also be extended to the bulk via thermal treatment up to 400 °C. It is demonstrated that the MoO 3 structure on metallic substrates is affected either by the diffusion of the metallic atoms inserted from the interface, which results in a formation of the meta-stable alloy phases in case of Cu, or by the introduction of the oxygen vacancies into the crystalline matrix in case of Al. The oxygen vacancy density in the MoO 3 films with a metallic interface can be tuned via optimal choice of the metal and treatment parameters such as temperature and oxygen partial pressure. Furthermore, the intrinsic defects present in the amorphous structure enhance the ionic mobility and diffusion of the metallic ions inside the crystalline structure.

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MoO3 films grown on polycrystalline Cu: Morphological, structural, and electronic properties

Cited by 16 publications

References 32 publications

Molybdenum Oxides Coatings for High Demanding Accelerator Components

Molybdenum Oxides Coatings for High Demanding Accelerator Components

Angular Dependence of Copper Surface Damage Induced by an Intense Coherent THz Radiation Beam

Metallic Interface Induced Ionic Redistribution within Amorphous MoO₃ Films

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MoO3 films grown on polycrystalline Cu: Morphological, structural, and electronic properties

Cited by 16 publications

References 32 publications

Molybdenum Oxides Coatings for High Demanding Accelerator Components

Molybdenum Oxides Coatings for High Demanding Accelerator Components

Angular Dependence of Copper Surface Damage Induced by an Intense Coherent THz Radiation Beam

Metallic Interface Induced Ionic Redistribution within Amorphous MoO3 Films

Contact Info

Product

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Metallic Interface Induced Ionic Redistribution within Amorphous MoO₃ Films