Sublimation process and physical properties of vapor grown γ-In2Se3 platelet crystals

Ajayakumar, C. J.; Kunjomana, A. G.

doi:10.1016/j.jcrysgro.2016.08.004

Cited by 7 publications

(3 citation statements)

References 15 publications

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“…The reported microstrain and defect density values are also a bit lower indicating higher crystal quality of the annealed films. The structural parameters calculated here are comparable with those reported as = D 22 nm and e = 6.67 × -10 3 for indium selenide crystals grown by the closed tube sublimation process in the absence of seed crystals and chemical transporting agents in a period of time that lasted 120 h [33]. Hence the main advantage of the current work are the crystallinity in a very short time not exceeding few seconds for an area of 1 cm 2 .…”

Section: Resultssupporting

confidence: 84%

Fast crystallization of InSe thin films via pulsed laser welding technique and effect of crystallinity on the optical and dielectric properties

Khusayfan,

Qasrawi,

Khanfar

et al. 2024

Phys. Scr.

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In the current study the crystalline phase of indium selenide thin films which were grown by the thermal evaporation technique is achieved via pulsed laser welding technique (PLW) in a second. The films crystallinity is achieved under various welding conditions including the pulse width (PW), repetition frequency (f_r ) and pulse diameter (d). The optimum parameters for obtaining well crystalline phase are PW=1.0 ms, f_r=10Hz and d=1.0 mm. PLW induced crystallinity showed preferred structure relating to monoclinic phase of InSe. Compositionally while amorphous films exhibited In2Se3 chemical structure, crystalline ones preferred InSe phase. Associated with this type of crystallinity, direct and indirect energy band gap values of 2.32 eV and 3.12 eV are determined. The crystalline films showed lower dielectric constant value accompanied with higher optical conductivity and higher terahertz cutoff frequency in the infrared range of light. In addition the dielectric dispersion spectra were treated using Drude-Lorentz model to read the optical conductivity parameters for the PLW assisted crystalline InSe terahertz resonators. The treatment showed that the crystallinity of the films resulted in improved free carrier density, longer relaxation times at femtosecond level, larger plasmon frequencies and higher drift mobility values. These features together with the response of terahertz cutoff frequency to IR excitations make crystalline InSe thin films promising for optoelectronic and terahertz technology applications.

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Section: Resultssupporting

confidence: 84%

Fast crystallization of InSe thin films via pulsed laser welding technique and effect of crystallinity on the optical and dielectric properties

Khusayfan,

Qasrawi,

Khanfar

et al. 2024

Phys. Scr.

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“…The peak at 950 cm −1 is attributed to W=O groups while the bands at 781, 585 and 474 cm −1 are assigned to M-O bonds (M=V or W). The band at 1080 cm −1 can be ascribed W-O and W-O-W vibrations [47,48].…”

Section: Characterization Of Adsorbentmentioning

confidence: 99%

Hydrothermal Synthesis and Characterization of K7V5W8O40·12H2O: Application to Rhodamine B Removal by Adsorption/Photocatalysis

et al. 2020

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The vanadotungstate K 7 V 5 W 8 O 40 •12H 2 O synthesized by hydrothermal route at 453 K was reported for the first time. The compound crystallizing in a Keggin type structure was characterized by powder X-ray diffraction, FTIR spectroscopy and UV-Vis diffuse reflectance; it was successfully tested for the removal of Rhodamine B (Rh B). The effects of contact time, initial concentration and pH were investigated. The adsorption capacity reached ~ 40% in aqueous solution within 16 h. Pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion models were applied to fit the experimental data. The pseudo-second-order was the best to describe the adsorption. The equilibrium isotherms were also analyzed by different models. Negative free enthalpy (ΔG) suggested that adsorption Rh B is spontaneous. The positive enthalpy (ΔH) entropy (ΔS) indicated endothermic process with an increase in the randomness of the solid/liquid interface. The compound showed 42% degradation of the remaining concentration after 4 h exposure to solar radiation.

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“…A binary compound is assumed to be stoichiometric when the atomic constituents are present in the ratio 1:1, 1:2, 2:3, 3:7 etc. (Ajayakumar & Kunjomana, 2016). samples is necessary for detecting the existence of undesirable components and for assessing the homogeneity, microstructure and crystalline phase.…”

Section: áG ¼ àmentioning

confidence: 99%

Facile synthesis of novel antimony selenide nanocrystals with hierarchical architecture by physical vapor deposition technique

Bibin

Kunjomana

2019

J Appl Cryst

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Stoichiometric antimony selenide (Sb 2 Se 3 ) nanocrystals have been successfully engineered by a facile physical vapor deposition method, employing a single precursor of polycrystalline Sb 2 Se 3 charge in a closed quartz ampoule under high vacuum without any foreign seed or extraneous chemical elements. This work underscores the efficacy of the vapor deposition process and provides synthetic strategies to scale down bulk Sb 2 Se 3 into novel nanostructures. The morphological evolution of the tailored architecture was examined on micro and nano size scales by scanning electron microscopy and high-resolution transmission electron microscopy. The intrinsic mechanism governing the nanostructure formation is revealed as layer-by-layer growth, related to the unique layered structure of Sb 2 Se 3 . The optical properties of the grown crystals were probed by UV-vis-NIR and photoluminescence tools. The band-gap values of the microfibers, nanorods, nanooctahedra and nanospheres estimated from UV-vis-NIR analysis are found to be 1.25, 1.47, 1.51 and 1.75 eV, respectively. Powder X-ray diffraction, energy-dispersive analysis by X-rays, X-ray photoelectron spectroscopy, Raman spectroscopy and photoluminescence studies confirmed the quality, phase purity and homogeneity of the as-grown nanostructures. The adopted physical vapor deposition method is thus shown to be a simple and elegant route which resulted in the enhancement of the band gap for the Sb 2 Se 3 samples compared with their counterparts grown by chemical methods. This approach has great potential for further applications in optoelectronics.

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Sublimation process and physical properties of vapor grown γ-In2Se3 platelet crystals

Cited by 7 publications

References 15 publications

Fast crystallization of InSe thin films via pulsed laser welding technique and effect of crystallinity on the optical and dielectric properties

Fast crystallization of InSe thin films via pulsed laser welding technique and effect of crystallinity on the optical and dielectric properties

Hydrothermal Synthesis and Characterization of K7V5W8O40·12H2O: Application to Rhodamine B Removal by Adsorption/Photocatalysis

Facile synthesis of novel antimony selenide nanocrystals with hierarchical architecture by physical vapor deposition technique

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