Here, single-crystal ZnS semiconductor nanoparticles were synthesized via a wet chemical method, exhibiting a spherical morphology with an average size of 26 nm. XRD profile revealed diffraction peaks along the (111), (220), and (311) planes, with an exceptionally strong intensity along (111). The texture coefficient confirmed a preferential orientation along this plane. Microstructural analysis based on XRD data revealed lower strain and dislocation density compared to previously reported works, strongly suggesting that the lower defect density in (111) preferentially oriented ZnS compared with other polycrystalline ZnS structures. Finally, the influence of the (111) preferential orientation on the emission properties of ZnS was examined through photoluminescence (PL) spectroscopy. The PL spectra show a lower intensity of the blue emission peak at 416 nm, further suggesting that ZnS semiconductor nanoparticles with a (111) preferential orientation have fewer defects and vacancies.

This study aims to prepare CdTe nanocrystals using wet-chemical method. XRD pattern confirms the hexagonal nature of the prepared nanocrystals. SHI-irradiation experiments have been performed at different fluences to study the SHI irradiation-influenced modification in structural and optical properties. TEM study confirms an increase in particle size after SHI irradiation. Further, different Williamson-Hall analysis models, the Size Strain Plot method, and the Halder-Wagner method have been used to determine the SHI-irradiated modification on the structural properties of prepared nanocrystals. Optical properties of synthesized and SHI-irradiated nanocrystals have been studied using Uv-Vis and photoluminescence analysis, which confirms modification in bandgap after SHI irradiation. Finally, the CIE diagram has been plotted for the color coordinates of synthesized hexagonal CdTe and SHI-irradiated CdTe nanocrystals at different fluences. All the studies confirm that the SHI irradiation can modify the structural and optical properties; hence, can be applied for different display purposes.

Nanocrystalline Mn-ferrite and Ni doped Mn-ferrite (NixMn1-xFe2O4, with x = 0, 0.25, 0.5, 0.75) have been synthesized through co-precipitation technique. Electron microscopic study shows spherical morphology whereas, X-ray diffraction (XRD) analysis confirms the cubic lattice geometry of the prepared sample. From the XRD analysis, average particle size and intrinsic strain in the sample have been determined considering the Classical Williamson Hall (CWH) method. Again, dislocation density present in the sample has been determined from the Modified Williamson Hall (MWH) methods. MWH method further confirms increase in dislocation density with Ni doping. A significant blue shift and decrease in intensity has been observed in the PL peak with the increase in the dislocation density, which indicates a strong influence of the dislocation density on the PL spectra. Structural and PL spectral analysis establishes the fact that there is a correlation between dislocation density and emission properties of Ni doped Mn-ferrite nanocrystals.

Swift heavy ion (SHI) irradiation deposits large amount of energy in the target material which thereby influences the structural features of the sample. In this work, the structural response of CdSe material has been studied under high energetic 120 MeV SHI irradiation. The long-range structural modifications of CdSe under SHI have been analyzed using Rietveld study. On the other hand, the short-range behavior of SHI irradiated CdSe has been studied using Pair distribution function (PDF), which can be interpreted as a distance map between two atoms in terms of a PDF peak. The small-box structural refinement of the samples has been performed using the PDFgui package for the study of modifications in the atomic arrangement after the SHI irradiation. In addition to this, structural characteristics such as unit cell parameters as determined from long-range (Rietveld) refinement are compared to that obtained from short-range (small-box) refinement. Moreover, atomic displacement factor for CdSe also has been determined to study the atomic disorder in the nanocrystal under the influence SHI irradiation. Finally, impact of SHI induced stress generated on the CdSe sample and its influence also has been studied based on the width of the PDF peak.

In this work, a wet chemical synthesis method has been used for the preparation of ZnS nanocrystals using the precursor Zn(NO3)2 (Zinc Nitrate) and Na2S (Sodium sulfide), where 3-Mercaptopropionic acid has been used as a capping agent. Morphological characterization of the prepared ZnS nanocrystals has been performed through HR-TEM and FE-SEM analysis and the average particle size has been obtained as approximately 26 nm. The HRTEM image also suggests the formation of smooth crystalline ZnS nanoparticles with dominance of the (111) plane. The XRD pattern firmly indicates dominance of (111) crystalline planes over the other planes. For this, different microstructural properties of prepared ZnS nanoparticles have been studied considering only the dominant (111) diffraction peak using single line Voigt method. Finally, the average particle size calculated from morphological analysis has been compared with the crystallite size calculated by XRD analysis through the Single line Voigt method. Calculated dislocation density value indicates presence of less defects states in the sample and confirms the growth of ZnS nanoparticles in a particular direction of (111) plane with pure crystalline nature.

Nanocrystalline CdSe has been synthesized via a wet chemical technique followed by characterized using XRD and HRTEM. Classical (CWH) and modified Williamson Hall (MWH) techniques have been used for the determination of microstructures based on the X-ray diffraction peak profile analysis (XDPPA). Rietveld refinement of the experimental XRD pattern provides the refined full width at half maximum (FWHM) of CdSe nanocrystals. Here, the output structural information as obtained from the Rietveld refinement method has been fed into the Quantum Espresso (QE) code for the determination of elastic constants of CdSe using the first principles method. Both the FWHM and elastic constants are used in CWH and MWH analysis. Since the MWH method considers the strain anisotropy of the crystals, it can provide a better fit than the CWH method. In addition to this, the MWH method has been used to find out the dislocations character present in the CdSe nanocrystals. Dislocations are important because these are responsible for inducing strain in the nanocrystals.

Swift heavy ion (SHI) irradiation can induce atomic scale structural reorientation. The amount of modification and reorientation due to irradiation depends on the specification of the respective heavy ions. Such a modification can directly affect the planar sequence and hence generate stacking faults in the material. Here, the effect of 120 MeV Ni10+ irradiation on the structural reorientation of CdSe as well as on the planar sequence has been studied through experimental (XRD) and theoretical (DFT) methods. The broadening of XRD peak along with the analysis of peak shift from the Bragg position has been used to determine the stacking fault energy (SFE). DFT based analysis has been performed to compare the stacking fault energy of pristine with the SHI irradiated sample. Finally, the effect of SHI irradiation on the density of states and electronic charge density has been studied, which indicates the presence of stacking faults in the CdSe nanocrystals after irradiation. (C) 2021 Elsevier B.V. All rights reserved.

Here, chemically synthesized CdS nanocrystals have been irradiated with swift heavy ions (SHI) with an aim to study the changes in its optical constants such as refractive index and dielectric constant along with the bandgap modification. Scanning electron microscopy (SEM) shows spherical morphology of the pristine CdS nanocrystals with an average size of 17 nm, which gets slightly deviated from its spherical morphology after SHI irradiation. X-ray diffraction (XRD) study reveals a change in the lattice structure of CdS nanocrystals from cubic to hexagonal phase due to irradiation. Structural information obtained from the XRD data has been fed as an initial input parameter in the first principles study (DFT + U) using the Quantum Espresso package for determining refractive index, dielectric constant, band gap and thermal properties theoretically. All these theoretically obtained values of optical constants match approximately with the values obtained from the experimental UV-Visible data analysis. Finally, the value of threshold electronic energy loss has been determined from the Thermal spike model.

Engineering of surface and structural properties of a sample by ion beam technology has got tremendous attention in recent times. Here, surface modification in CdSe nanocrystalline thin film due to 120 MeV Ag swift heavy ions (SHI) irradiation has been studied through Stopping and Range of Ions in Matter (SRIM)/Transport of ions in matter (TRIM) package in terms of sputtering yield and average surface binding energy. From this study, average range has been obtained as 1.6 mu m and average surface binding energy as 1.7 eV. SHI deposits huge energy to the atomic lattice and that displaces the lattice atoms from their original positions, which has been utilized here to obtain displacement damage. The damage profile has been studied as a function of dpa, which shows that the maximum displacement damage peaks is at 1.5 mu m for CdSe due to 120 Mev Ag ions irradiation.

In the present work, chemically synthesized cadmium selenide (CdSe) nanocrystals, which have a cubic lattice structure as per X-ray diffraction (XRD) analysis, has been irradiated with 120 MeV Ni10+ swift heavy ions (SHI) for the study of their structural modification. A significant change in the lattice structure has been found with different ion fluence of 120 MeV Ni10+ irradiation, which may be due to the high electronic energy loss of SHI. AFM analysis also shows changes in morphological properties with ion irradiation. The evolution of lattice structure with different fluence has been studied using double ion impact model. Further, SHI induced cubic to hexagonal transformation effect the microstructural parameters such as intrinsic strain, dislocation density of CdSe nanocrystals. SHI induced microstructural modifications have also been studied with the help of Variance model.

Swift heavy ion (SHI) irradiation modifies the physical and chemical properties of semiconductor sample like CdSe nanocrystals by inducing vacancies and structural change in the lattice system. Here, the atomistic strain analysis has been performed using molecular dynamics (MD) simulation on the SHI irradiated CdSe nanocrystals by approximating interatomic interaction as (ZBL) potential. MD simulation based on LAMMPS package has been employed for better understanding the time response of the sample with swift heavy ion irradiation. The primary knock-on atom (PKA) method has been used for the simulation that starts the cascade of energy transfer, which triggers the displacement of atoms. Initial parameters of PKA have been obtained from the SRIM simulation of the irradiation effect of 120 MeV Ni ions. Finally, the time evolution of the system has been studied.

Swift Heavy ion (SHI) irradiation is a powerful technique for the modification of various properties of a material. Here, CdS nanocrystals have been prepared by a chemical method and subsequently irradiated by 120 MeV Ni10+ heavy ions at IUAC, New Delhi. X-ray diffraction (XRD) analysis has been performed to study the change in structural properties before and after the irradiation. Rietveld refinement confirms the transformation of CdS nanocrystals from cubic to hexagonal phase after SHI irradiation. Further, the output information of the Rietveld refinement has been used in the Quantum espresso code as an input parameter to study the change in the elastic constants due to the SHI irradiation by first principles method. Now, using those elastic constant values, microstructural parameters of CdS nanocrystals has been obtained from the XRD peak broadening of the pristine and SHI irradiated samples. (C) 2020 Elsevier B.V. All rights reserved.

In this work, cadmium selenide (CdSe) nanocrystals have been chemically synthesized and subsequently characterized by SEM, XRD and Raman Study. XRD pattern of pristine CdSe nanocrystals show cubic lattice structure with average particle size of 34 nm approximately. CdSe nanocrystals have been irradiated by 120 MeV swift Ni10+ and Ag7+ heavy ions (SHI) at different ion fluences of 1 x 10(11), 1 x 10(12) and 3 x 10(13) ions/cm(2). XRD patterns reveal a structural phase transformation from cubic to hexagonal phase in the SHI irradiated CdSe nanocrystals at highest fluence in both the cases of Ni10+ and Ag7+ ions. Since the deposited energy loss of Ni10+ and Ag7+ ions is different, the evolution of hexagonal phase with the ion fluences is also different. Here, a comparative analysis of the effect of Ni10+ and Ag7+ ion on CdSe nanocrystals have been studied using Garvie and Nicholson model to understand the mechanism of the phase transformation. Further, the effect of both the swift ion on the structural properties of CdSe nanocrystals has also been studied with the help of Raman Spectral analysis.

Cadmium selenide (CdSe) nanoparticles have been prepared by chemical method using sodium hydrogen selenide precursor and cadmium chloride. X-ray diffraction (XRD) study confirms the crystalline nature of the CdSe nanoparticles with Cubic Zinc blende lattice structure, whereas transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis indicate the spherical morphology of the prepared nanoparticles, having an average size of approximately 36nm. Here, Williamson-Hall (W-H), Size-Strain Plot (SSP), and Halder-Wagner Method (H-W) have been used to investigate the particle size and the intrinsic strain from the XRD peak broadening analysis. Further, in W-H method, different models have been considered for the determination of physical and microstructural parameters such as strain, stress, and energy density. The average particle size that has been determined from Williamson-Hall, Size-Strain, Halder-Wagner Methods are compared with HR-TEM, AFM, and SEM analysis.

The interaction of 120 MeV Ag7+ swift ions with the chemically prepared cadmium selenide nanocrystals have been studied in this work through XRD data analysis. Atomic force microscopic study provides the information that with SHI irradiation, average grain size increases and surface modification takes place. Thermal spike model gives an idea about the changes in the lattice structure due to SHI irradiation, which induces lattice geometry reorientation. Such changes in lattice geometry result in modification of band structure as well as density of states of the bands and therefore modification in the band gap of the prepared sample takes place. Theoretical study of the band gap tuning has been performed using first principles based on Quantum espresso Code through PBE + U analysis, which supports the results as obtained from experimental diffuse reflectance spectra and Photoluminescence spectral study. Hence, both the experimental and theoretical study confirm the band gap engineering of CdSe nanocrystals through SHI irradiation. (C) 2020 Elsevier B.V. All rights reserved.