Growth and characterization of electrosynthesized iron selenide thin films

A comparative study on the physicochemical properties of tungsten oxide (WO 3 ) thin films synthesized using peroxotungstic acid (PTA) and ammonium tungstate (AT) by simple spray pyrolysis technique is reported. X-ray diffraction patterns show that the films deposited using both the precursors are polycrystalline with monoclinic crystal structure. The x-ray photoelectron spectroscopy studies confirm that the films are sub-stoichiometric with O/W ratios of 2.93 and 2.87, respectively, for typical PTA and AT films. Tungsten (W) exists in two chemical states, 5+ and 6+. Scanning electron microscopy images show the uniform and dense network of wires in PTA films, while the films deposited using AT possess a porous structure with small grains. Electrical and dielectric studies show that films are highly resistive and possess high dielectric constant. The near ultra-violet, blue, green and weak red emissions due to defects were observed in the photoluminescence studies. Properties of the WO 3 thin films reported here are suitable for gas sensor applications. Films deposited using PTA are more functional than those deposited using AT.

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“…This is attributed to the decrease in film thickness at higher substrate temperatures which in turn decreases the crystalline component. 25 …”

Section: X-ray Diffraction Studiesmentioning

confidence: 99%

Effect of Substrate Temperature on the Properties of Sprayed WO3 Thin Films Using Peroxotungstic Acid and Ammonium Tungstate: A Comparative Study

Ganbavle

Kim

Rajpure

2015

Journal of Elec Materi

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“…Thin films of binary 1:1 iron selenides and tellurides FeCh (Ch = Se, Te) were extensively studied since the early 1970s. Optical, magnetic and others physical properties were investigated [1][2][3][4][5][6][7], but resistivity has not been studied at temperatures below 100 K, and thus the occurrence of superconductivity was not recognized. This was probably due to the presence of iron that was historically considered detrimental for superconductivity.…”

Section: Introductionmentioning

confidence: 99%

Superconducting properties of iron chalcogenide thin films

Mele

2012

Science and Technology of Advanced Materials

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Iron chalcogenides, binary FeSe, FeTe and ternary FeTe x Se 1−x , FeTe x S 1−x and FeTe:O x , are the simplest compounds amongst the recently discovered iron-based superconductors. Thin films of iron chalcogenides present many attractive features that are covered in this review, such as: (i) easy fabrication and epitaxial growth on common single-crystal substrates; (ii) strong enhancement of superconducting transition temperature with respect to the bulk parent compounds (in FeTe 0.5 Se 0.5 , zero-resistance transition temperature T bulk c0 = 13.5 K, but T film c0 = 19 K on LaAlO 3 substrate); (iii) high critical current density (J c ∼ 0.5 × 10 6 A cm 2 at 4.2 K and 0 T for FeTe 0.5 Se 0.5 film deposited on CaF 2 , and similar values on flexible metallic substrates (Hastelloy tapes buffered by ion-beam assisted deposition) with a weak dependence on magnetic field; (iv) high upper critical field (∼50 T for FeTe 0.5 Se 0.5 , B c2 (0), with a low anisotropy, γ ∼ 2). These highlights explain why thin films of iron chalcogenides have been widely studied in recent years and are considered as promising materials for applications requiring high magnetic fields (20-50 T) and low temperatures (2-10 K).

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“…Lee et al proposed that the introduction of STO or BaTiO 3 (BTO) thin buffer layers on LAO and LSAT substrates was effective for improving the film quality [53]. The Co-doped Ba122 films on these buffer layers showed a sharp superconducting transition (T onset c ≈ 22.8 K, T zero c ≈ 21.5 K, ∆T c ≈ 1.3 K), and the self-field critical current density, J c , was as high as 4.5 MA/cm 2 at 4.2 K. Iida et al found another useful buffer layer, that is, metal iron with a body-centered-cubic (bcc) structure whose bond length along [110] direction was close to that along [100] direction of Ba122 [54][55][56]. Indeed, by introducing the bcc-Fe buffer layer with thickness of ∼15 nm, the obtained values of T c for Co-doped Ba122 films on LSAT and MgO substrates increased by ∼2-4 K compared to those of films on bare these substrates.…”

Section: -Systemmentioning

confidence: 99%

“…There are also attempts to grow FeSe films by electrochemical techniques [109][110][111][112][113][114] and chemical vapor deposition techniques [115,116]. However, T zero c comparable to that of bulk samples has not been obtained or the resistivity was not measured in these films.…”

Section: -Systemmentioning

confidence: 99%

Comparative Review on Thin Film Growth of Iron-Based Superconductors

2017

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Abstract:Since the discovery of the novel iron-based superconductors, both theoretical and experimental studies have been performed intensively. Because iron-based superconductors have a smaller anisotropy than high-T c cuprates and a high superconducting transition temperature, there have been a lot of researchers working on the film fabrication of iron-based superconductors and their application. Accordingly, many novel features have been reported in the films of iron-based superconductors, for example, the fabrication of the epitaxial film with a higher T c than bulk samples, the extraction of the metastable phase which cannot be obtained by the conventional solid state reaction, and so on. In this paper, we review the progress of research on thin film fabrications of iron-based superconductors, especially the four categories: LnFeAs(O,F) (Ln = Lanthanide), AEFe 2 As 2 (AE = Alkaline-earth metal), FeCh (Ch = Chalcogen), and FeSe monolayer. Furthermore, we focus on two important topics in thin films of iron-based superconductors; one is the substrate material for thin film growth on the iron-based superconductors, and the other is the whole phase diagram in FeSe 1−x Te x which can be obtained only by using film-fabrication technique.

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Growth and characterization of electrosynthesized iron selenide thin films

Cited by 92 publications

References 17 publications

Effect of Substrate Temperature on the Properties of Sprayed WO3 Thin Films Using Peroxotungstic Acid and Ammonium Tungstate: A Comparative Study

Effect of Substrate Temperature on the Properties of Sprayed WO3 Thin Films Using Peroxotungstic Acid and Ammonium Tungstate: A Comparative Study

Superconducting properties of iron chalcogenide thin films

Comparative Review on Thin Film Growth of Iron-Based Superconductors

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