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Narayana Perumal Rajesh

Bio: Narayana Perumal Rajesh is an academic researcher from Sri Sivasubramaniya Nadar College of Engineering. The author has contributed to research in topics: Crystal & Single crystal. The author has an hindex of 23, co-authored 70 publications receiving 1280 citations. Previous affiliations of Narayana Perumal Rajesh include Anna University & National Tsing Hua University.


Papers
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TL;DR: In this paper, single crystals of cadmium thiourea acetate (CTA) have been grown from a low-temperature solution method by a slow evaporation method at ambient temperature.

82 citations

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TL;DR: In this paper, the negative nonlinear optical parameters of 2-aminopyridinium trichloroacetate were derived by the Z-scan technique, and high-resolution X-ray diffraction measurements were performed to analyze the structural perfection of the grown crystals.

68 citations

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TL;DR: In this paper, a semi-organic nonlinear optical crystal Bisthiourea-zinc acetate (BTZA) has been grown and characterized in aqueous solution.

64 citations

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TL;DR: In this paper, a novel organic nonlinear optical material 4methoxy benzaldehyde-N-methyl-4stilbazolium tosylate has been synthesized and good optical quality crystals were grown by slow cooling solution growth technique.

58 citations

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TL;DR: In this article, the influence of the organic additives on the optical and mechanical properties of KDP crystals has been studied and it has been observed that the addition of organic additives improves the mechanical strength of the crystal.

56 citations


Cited by
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Journal ArticleDOI
TL;DR: A review of the metal sulphide precipitation literature can be found in this article, where the authors summarized the current work and suggested potential for future consolidation in the field of metal sulfide precipitation.

513 citations

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TL;DR: In this paper, the FFT Raman and IR spectra of the benzaldehyde phenylhydrazone (BPH) were analyzed with the help of B3LYP density functional theory.

382 citations

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TL;DR: The effect of dopants (over a concentration range from 1 to 10 mol %) on the growth process, crystalline perfection, and nonlinear optical properties of ammonium dihydrogen phosphate (NH4H2PO4, ADP) single crystals grown by a slow evaporation solution growth technique has been investigated in this paper.
Abstract: The effect of dopants (over a concentration range from 1 to 10 mol %), namely KCl and oxalic acid (C2H2O4·2H2O, Oxa), on the growth process, crystalline perfection, and nonlinear optical (NLO) properties of ammonium dihydrogen phosphate (NH4H2PO4, ADP) single crystals grown by a slow evaporation solution growth technique has been investigated. The high-resolution X-ray diffraction (HRXRD) studies used to evaluate crystalline perfection reveal some interesting features on the ability of accommodating the dopants by the crystalline matrix. The remarkable and systematic increase in the broadness and asymmetry of the diffraction curves as the concentration increases clearly indicates that the dopants predominantly occupied the interstitial positions in the crystalline matrix. Due to the larger size of the Oxa molecule, the crystalline matrix could not accommodate these dopants, which led to the formation of a very low angle (tilt angle <1′) internal structural grain boundaries at high concentrations. The rela...

180 citations

Journal ArticleDOI
TL;DR: In this article, the influence of organic dopants on the second harmonic generation efficiency of tristhiourea zinc(II) sulfate (ZTS), ammonium dihydrogen phosphate (ADP) and potassium hydrogen phthalate (KHP) was investigated using high-resolution X-ray diffractometry and scanning electron microscopy.
Abstract: To reveal the influence of complexing agents on crystalline perfection, tristhiourea zinc(II) sulfate (ZTS), ammonium dihydrogen phosphate (ADP) and potassium hydrogen phthalate (KHP) crystals grown by slow-evaporation solution growth technique using low concentrations (5 x 10 -3 M) of dopants like ethylenediamminetetraacetic acid (EDTA) and 1,10-phenanthroline (phen) were characterized by high-resolution X-ray diffractometry (XRD) and scanning electron microscopy (SEM). High-resolution diffraction curves (DCs) recorded for ZTS and ADP crystals doped with EDTA show that the specimen contains an epilayer, as observed by the additional peak in the DC, whereas undoped specimens do not have such additional peaks. On etching the surface layer, the additional peak due to the epilayer disappears and a very sharp DC is obtained, with full width at half-maximum (FWHM) of less than 10 arcsec, as expected from the plane wave dynamical theory of X-ray diffraction for an ideally perfect crystal. SEM micrographs also confirm the existence of an epilayer in doped specimens. The ZTS specimen has a layer with a rough surface morphology, having randomly oriented needles, whereas the ADP specimen contains a layer with dendric structure. In contrast to ADP and ZTS crystals, the DC of phen-doped KHP shows no additional peak, but it is quite broad (FWHM = 28 arcsec) with a high value of integrated intensity, p (area under the DC). The broadness of the DC and the high value of p indicate the formation of a mosaic layer on the surface of the crystal. However, similar to ADP and ZTS, the DC recorded after etching the surface layer of the KHP specimen shows a very sharp peak with an FWHM of 8 arcsec. An SEM photograph of phen-doped KHP shows deep cracks on the surface, confirming the mosaicity. After removing the surface layer, the SEM pictures reveal a smooth surface. A similar trend is observed with other complexing agents, like oxalic acid, bipy and picolinic acid. However, only typical examples are described in the present article where the effects were observed prominently. The investigations on ZTS, ADP and KHP crystals, employing high-resolution XRD and SEM studies, revealed that some organic dopants added to the solution during the growth lead to the formation of a surface layer, due to complexation of these dopants with the trace metal ion impurities present in the solution, which prevents the entry of impurities, including the solvent, into the crystal, thereby assisting crystal growth with high crystalline perfection. The influence of organic dopants on the second harmonic generation efficiency is also investigated.

177 citations

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TL;DR: In this paper, X-ray diffraction (XRD), Fourier transforms infrared (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), and spectroscopic ellipsometry (SE) were used to characterise the polycrystalline thin films.
Abstract: Cadmium sulphide (CdS) polycrystalline thin films were deposited on ultrasonically cleaned silicon wafers (1 0 0) by thermal evaporation technique in a vacuum of about 2 × 10 −5 Torr. X-ray diffraction (XRD), Fourier transforms infrared (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), and spectroscopic ellipsometry (SE) were used to characterise the polycrystalline thin films. The thickness of the films as estimated by the ellipsometry, found to be in the range of 263–282 nm. The values of refractive index ( n ) and extinction coefficient ( k ) of thin films are found to decrease with wavelength. XRD results indicated the formation of cadmium sulphide thin films with hexagonal phase. The films have preferred orientation along (0 0 2) plane. The lattice parameters are calculated as a = 4.135 A and c = 6.742 A, which are in good agreement with the reported data. The optical properties of the polycrystalline thin films are investigated systematically by spectroscopic ellipsometry (SE) and a blue shift compared with bulk cadmium sulphide is observed. The optical band gap of the thin film is estimated to be 2.50 eV. The structural and optical properties of the films fabricated by the thermal evaporation technique are found to be desirable for optoelectronic devices.

149 citations