Optical properties of oxygen-containing yttrium hydride thin films during and after the deposition

Zubkins, Mārtiņš; Aulika, I.; Strods, E.; V., Vibornijs,; Bikse, Liga; Šarakovskis, Anatolijs; Chikvaidze, G.; Gabrusenoks, J.; Arslan, H.; Purans, J.

doi:10.1016/j.vacuum.2022.111218

Cited by 12 publications

(4 citation statements)

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“…Similarly, we find that upon air exposure the as-deposited CaY hydride films become semiconducting, although some of the films already seem to incorporate oxygen when measured in the glovebox before air exposure (glovebox: [H 2 O] and [O 2 ] < 0.1 ppm), perhaps due to oxidation from residual gases. 19 For this work, we used only one p dep of 0.5 Pa to survey the effect of Ca doping on the photochromic properties using a range of Ca concentrations (at. %).…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Following from our previous work on REH 3–2 x O x thin films (RE = Sc, Y, Nd, Gd, Dy, and Er), − the combined Ar/H 2 deposition pressure ( p dep ) affects the as-deposited RE dihydride; we found that if p dep is below a critical pressure ( p * ∼ 0.4 Pa for Y), , the film remains a metallic RE dihydride, but above p *, it forms a semiconducting oxyhydride upon ambient air exposure (Figure ). Similarly, we find that upon air exposure the as-deposited CaY hydride films become semiconducting, although some of the films already seem to incorporate oxygen when measured in the glovebox before air exposure (glovebox: [H 2 O] and [O 2 ] < 0.1 ppm), perhaps due to oxidation from residual gases . For this work, we used only one p dep of 0.5 Pa to survey the effect of Ca doping on the photochromic properties using a range of Ca concentrations (at.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Aliovalent Calcium Doping of Yttrium Oxyhydride Thin Films and Implications for Photochromism

et al. 2022

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To develop an understanding of the photochromic effect in rare-earth metal oxyhydride thin films (REH 3–2 x O x , here RE = Y), we explore the aliovalent doping of the RE cation. We prepared Ca-doped yttrium oxyhydride thin films ((Ca z Y 1– z )H x O y ) by reactive magnetron cosputtering with Ca doping concentrations between 0 and 36 at. %. All of the films are semiconductors with a constant optical band gap for Ca content below 15%, while the band gap expands for compositions above 15%. Ca doping affects the photochromic properties, resulting in (1) a lower photochromic contrast, likely due to a lower H – concentration, and (2) a faster bleaching speed, caused by a higher pre-exponential factor. Overall, these results point to the importance of the H – concentration for the formation of a “darkened” phase and the local rearrangement of these H – for the kinetics of the process.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

Aliovalent Calcium Doping of Yttrium Oxyhydride Thin Films and Implications for Photochromism

et al. 2022

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“…The as-deposited REH 2 thin films were then oxidized in ambient conditions by exposure to air. Because the air-oxidation is largely a self-limiting process, [13,27] the samples were given a 14 + day rest period before further characterization.…”

Section: Sample Preparationmentioning

confidence: 99%

Large Polaron Conduction, Photoconductivity, and Photochromism in GdO_xH₃_−2x Oxyhydride Thin Films

Colombi

Boshuizen

Chaykina

et al. 2023

Advanced Optical Materials

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At ambient conditions, rare‐earth oxyhydride thin films show reversible photochromism and photoconductivity, while their mechanism and relation are still unclear. In this work, this question is explored with in situ time‐resolved measurements of both optical and transport properties of Gd‐based oxyhydride thin films. It is found that p‐type large polaron conduction is the initial mechanism of charge transport; however, upon photo‐darkening, a 104‐fold increase of conductivity occurs, and n‐type carriers become dominant. Further, photochromism and photoconductivity are shown to originate from a single process, as indicated by the fact that the photoconductivity is exponentially proportional to the increase of optical absorption. This exponential relation, notably, cannot stem from any of the optically absorbing species thought responsible for photochromism and, therefore, suggests that their formation is accompanied by a concerted increase of negative charge carriers in the Gd oxyhydride films.

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“…The technology is suitable for application on large-area surfaces and can be performed on various substrates, like polyethylene terephthalate (PET) sheets, different types of glass, metals, and even textiles [2,3]. Transparent coatings with anti-microbial, photochromic, electrochromic, electroconductive, and other effects can be obtained [4][5][6][7]. Surface modification with a magnetron-sputtered coating can also be utilized to enhance mechanical or chemical stability [4].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Antibacterial and Antiviral Properties of ZnO and Cu Coatings Deposited by Magnetron Sputtering: Evaluation of Cell Viability and ROS Production

Vibornijs,

Zubkins,

Strods

et al. 2023

Coatings

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The development and testing of antimicrobial coatings continues to be a crucial approach, considering the ongoing emergence of antibiotic-resistant bacteria and the rapid transmission of highly pathogenic viruses. In this study, three types of coatings—pure metallic copper (Cu), zinc oxide (ZnO), and a three-layer zinc oxide and copper mixed coating (ZnO/Cu/ZnO)—were deposited by magnetron sputtering on polyethylene terephthalate substrates to evaluate their antimicrobial potential using various microorganisms, including viruses. Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria were used for the assessment of antibacterial properties. Antiviral testing was performed using MS2 bacteriophage and replication-deficient Semliki Forest virus, both representing single-stranded RNA-containing viruses. The samples’ ability to cause reactive oxygen species formation was measured, and the effect on bacterial metabolic activity was evaluated. Cu-coated samples showed high inhibitory activity (>95%) against E. coli and S. aureus bacteria, as well as against tested viruses (SFV and MS2). The antibacterial and antiviral properties of ZnO/Cu/ZnO and ZnO coatings were not significant. Although ZnO/Cu/ZnO and ZnO caused inhibition of the metabolic activity of the bacteria, it was insufficient for complete bacteria eradication. Furthermore, significant reactive oxygen species (ROS) production was detected only for single Cu-coated samples, correlating with the strong bacteria-killing ability. We suppose that the ZnO layer exhibited a low release of Zn ions and prevented contact of the Cu layer with bacteria and viruses in the ZnO/Cu/ZnO coating. We conclude that current ZnO and Cu-ZnO-layered coatings do not possess antibacterial and antiviral activity.

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Optical properties of oxygen-containing yttrium hydride thin films during and after the deposition

Cited by 12 publications

References 44 publications

Aliovalent Calcium Doping of Yttrium Oxyhydride Thin Films and Implications for Photochromism

Aliovalent Calcium Doping of Yttrium Oxyhydride Thin Films and Implications for Photochromism

Large Polaron Conduction, Photoconductivity, and Photochromism in GdO_xH₃_−2x Oxyhydride Thin Films

Analysis of Antibacterial and Antiviral Properties of ZnO and Cu Coatings Deposited by Magnetron Sputtering: Evaluation of Cell Viability and ROS Production

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Optical properties of oxygen-containing yttrium hydride thin films during and after the deposition

Cited by 12 publications

References 44 publications

Aliovalent Calcium Doping of Yttrium Oxyhydride Thin Films and Implications for Photochromism

Aliovalent Calcium Doping of Yttrium Oxyhydride Thin Films and Implications for Photochromism

Large Polaron Conduction, Photoconductivity, and Photochromism in GdOxH3−2x Oxyhydride Thin Films

Analysis of Antibacterial and Antiviral Properties of ZnO and Cu Coatings Deposited by Magnetron Sputtering: Evaluation of Cell Viability and ROS Production

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Large Polaron Conduction, Photoconductivity, and Photochromism in GdO_xH₃_−2x Oxyhydride Thin Films