Nickel sulphate hexahydrate (NSH) and potassium magnesium nickel sulphate hexahydrate (KMNSH) single crystals were grown by slow evaporation method. The grown NSH crystal was found to crystallize in tetragonal system with space group P41 21 2 and KMNSH in monoclinic system with space group P121/c. The optical band gap energies of the grown crystals using UV-Vis spectral results for the doped and undoped NSH crystals were calculated. The presence of various functional groups in the crystal was identified by FTIR analysis. The thermal behaviour of the grown crystal has been studied by TGA/DTA analysis.

Present work is influenced by the requirement of investigation of rare earth intermetallics due to the nonavailability of theoretical details and least information from experimental results. An attempt has been made to analyse the structural, electronic, magnetic and thermal properties of DyNi using full potential linear augmented plane wave method based on density functional theory. DyNi differs from other members of lanthanides nickelates as in ground state it crystallizes in FeB phase rather than orthorhombic CrB structure. The equilibrium lattice constant, bulk modulus, and pressure derivative of bulk modulus are presented in four polymorphs (FeB, CrB, CsCl and NaCl) of DyNi. At equilibrium the cell volume of DyNi for FeB structure has been calculated as 1098.16 Bohr3 which is comparable well with the experimental value 1074.75 Bohr3. The electronic band structure has been presented for FeB phase. The results for thermal properties, namely, thermal expansion coefficient, Gruneisen parameter, specific heat and Debye temperature at higher pressure and temperatures have been reported. The magnetic moments at equilibrium lattice constants have also been tabulated as the rare earth ions associated with large magnetic moments increase their utility in industrial field for the fabrication of electronic devices due to their magnetocaloric effect used in magnetic refrigeration.

In2S3 films have been successfully deposited on Corning glass substrates via chemical bath deposition (CBD) method using acetic acid as a novel complexing agent. The layers were grown by employing synthesis using indium sulphate and thioacetamide (TA) as precursors by varying TA concentration in the range of 0.1–0.5 M, keeping other deposition parameters constant. Energy dispersive X-ray analysis (EDAX) revealed an increase of S/In ratio in the films with the increase of TA concentration in the solution. The X-ray diffraction (XRD) analysis indicated a change in preferred orientation from (311) plane related to cubic structure to the (103) direction corresponding to the tetragonal crystal structure. The evaluated crystallite size varied in the range of 15–25 nm with the increase of TA concentration. Morphological analysis showed that the granular structure and the granular density decrease with the raise of TA concentration. The optical properties of the layers were also investigated using UV-Vis-NIR analysis, which indicated that all the In2S3 films had the optical transmittance >60% in the visible region, and the evaluated energy band varied in the range of 2.87–3.32 eV with the change of TA concentration. Further, a thin film heterojunction solar cell was fabricated using a novel absorber layer, SnS, with In2S3 as a buffer. The unoptimized SnS/In2S3/ZnO:Al solar cell showed a conversion efficiency of 0.6%.

Molybdenum oxide (MoO3) films were deposited on glass and silicon substrates held at temperature 473 K by RF magnetron sputtering of molybdenum target at various oxygen partial pressures in the range 8×10-5–8×10-4 mbar. The deposited MoO3 films were characterized for their chemical composition, crystallographic structure, surface morphology, chemical binding configuration, and optical properties. The films formed at oxygen partial pressure of 4×10-4 mbar were nearly stoichiometric and nanocrystalline MoO3 with crystallite size of 27 nm. The Fourier transform infrared spectrum of the films formed at 4×10-4 mbar exhibited the characteristics vibrational bands of MoO3. The optical band gap of the films increased from 3.11 to 3.28 eV, and the refractive index increased from 2.04 to 2.16 with the increase of oxygen partial pressure from 8×10-5 to 8×10-4 mbar, respectively. The electrochromic performance of MoO3 films formed on ITO coated glass substrates was studied and achieved the optical modulation of about 13% with color efficiency of about 20 cm2/C.

Copper nickel oxide (CuNiO2) films were deposited on glass and silicon substrates using RF magnetron sputtering of equimolar Cu50Ni50 alloy target at different sputter powers in the range of 3.1–6.1 W/cm2. The effect of sputter power on the chemical composition, crystallographic structure, chemical binding configuration, surface morphology, and electrical and optical properties of CuNiO2 films was investigated. The films formed at sputter power of 5.1 W/cm2 were of nearly stoichiometric CuNiO2. Fourier transform infrared spectroscopic studies indicated the presence of the characteristic vibrational bands of copper nickel oxide. The nanocrystalline CuNiO2 films were formed with the increase in grain size from 75 to 120 nm as the sputter power increased from 3.1 to 5.1 W/cm2. The stoichiometric CuNiO2 films formed at sputter power of 5.1 W/cm2 exhibited electrical resistivity of 27 Ωcm, Hall mobility of 21 cm2/Vsec, and optical bandgap of 1.93 eV.

Cu4SnS4 films of different thicknesses were prepared by thermal coevaporation technique on glass substrates at a constant substrate temperature of 400°C. The layer thickness was varied in the range 0.25–1 μm. The composition analysis revealed that all the evaporated films were nearly stoichiometric. The XRD patterns indicated the presence of a strong (311) peak as the preferred orientation, following the orthorhombic crystal structure corresponding to Cu4SnS4 films. Raman analysis showed a sharp peak at 317 cm−1, also related to Cu4SnS4 phase. The optical transmittance spectra suggested that the energy band gap decreased from 1.47 eV to 1.21 eV with increase of film thickness. The hot-probe test revealed that the layers had p-type electrical conductivity. A decrease of electrical resistivity was observed with the rise of film thickness.

We have investigated the effect of pH on the structural and optical properties of chemical coprecipitated Cu2ZnSnS4 (CZTS) nanoparticles. The CZTS nanoparticles have been successfully synthesized at different pH values ranging from 6 to 9, keeping all other deposition parameters as constant. X-ray diffraction and Raman studies confirmed the Kesterite structure. The powders synthesized at a pH value of 8 exhibited preferred orientation along (112) and (220) with near stoichiometric ratio. The as synthesized nanoparticles exhibited direct band gap of 1.4 eV which is an optimum value for the absorber layer in the fabrication of photovoltaic cells.

We investigate the excitation kinetics of a repulsive impurity doped quantum dot initiated by the application of Gaussian white noise. In view of a comprehensive research we have considered both additive and multiplicative noise (in Stratonovich sense). The noise strength and the dopant location have been found to fabricate the said kinetics in a delicate way. Moreover, the influences of additive and multiplicative nature of the noise on the excitation kinetics have been observed to be prominently different. The investigation reveals emergence of maximization and saturation in the excitation kinetics as a result of complex interplay between various parameters that affect the kinetics. The present investigation is believed to provide some useful perceptions of the functioning of mesoscopic systems where noise plays some profound role.

We consider a two-dimensional fermion system on a square lattice described by a mean-field Hamiltonian involving the singlet id-density wave (DDW) order, assumed to correspond to the pseudo-gap (PG) state, favored by the electronic repulsion and the coexisting -wave superconductivity (DSC) driven by an assumed attractive interaction within the BCS framework. Whereas the single-particle excitation spectrum of the pure DDW state consists of the fermionic particles and holes over the reasonably conducting background, the coexisting states corresponds to Bogoliubov quasi-particles in the background of the delocalized Cooper pairs in the momentum space. We find that the two gaps in the single-particle excitation spectrum corresponding to PG and DSC, respectively, are distinct and do not merge into one “quadrature” gap if the nesting property of the normal state dispersion is absent. We show that the PG and DSC are representing two competing orders as the former brings about a depletion of the spectral weight available for pairing in the anti-nodal region of momentum space where the superconducting gap is supposed to be the largest. This indicates that the PG state perhaps could not be linked to a preformed pairing scenario. We also show the depletion of the spectral weight below at energies larger than the gap amplitude. This is an important hallmark of the strong coupling superconductivity.

The high-pressure structural phase transition of semiconductor PbS has been investigated, using the three body potential (TBP) model. Phase transition pressures are associated with a sudden collapse in volume. The phase transition pressures and related volume collapses obtained from this model show a generally good agreement with available results. Moreover, the elastic properties of PbS are also investigated.

Phase transition temperatures of ferroelectric liquid crystals ((S)-(-)-2-methylbutyl 4′-(4″-n-alkanoyloxybenzoyloxy) biphenyl-4-carboxylates (where n=16 and 18)) are studied through two techniques of image analysis. One is a statistical method, applied to compute the statistical parameters from the textures of each sample and the other, computation of Legendre moments being applied as image moment analysis, both of which are considered as a function of temperature. The textures of the samples are recorded with the polarizing optical microscope (POM) attached to the hot stage and high resolution camera. The phase transition temperatures of samples are inferred by the abrupt changes in the computed parameter values. The results obtained from the present methodology are in good agreement with those published in earlier literature done by the different techniques, like differential scanning calorimetry (DSC).

Thin films of silver-copper-oxide were deposited on glass substrates by RF magnetron sputtering of Ag80Cu20 target under various oxygen partial pressures in the range 5×10−3–8×10−2 Pa. The effect of oxygen partial pressure on the crystallographic structure and surface morphology and electrical and optical properties was systematically studied and the results were reported. The oxygen content in the films was correlated with the oxygen partial pressure maintained during the growth of the films. The films which formed at low oxygen partial pressure of 5×10−3 Pa were mixed in phase of Ag2Cu2O3 and Ag while those deposited at 2×10−2 Pa were grown with Ag2Cu2O3 and Ag2Cu2O4 phases. The films which formed at oxygen partial pressure of 2×10−2 Pa showed electrical resistivity of 2.3 Ωcm and optical band gap of 1.47 eV.

We performed the structure optimization of Co2TiAl based on the generalized gradient approximation (GGA) and linearized augmented plane wave (LAPW) method. The calculation of electronic structure was based on the full-potential linear augmented plane wave (FP-LAPW) method and local spin density approximation exchange correlation LSDA+U. We also studied the impact of the Hubbard potential or onsite Coulomb repulsion (U) on electronic structure; the values are varied within reasonable limits to study the resulting effect on the physical properties of Co2TiAl system. The calculated density of states (DOS) shows that half-metallicity of Co2TiAl decreases with the increase in U values.

Cluster formation in a two-dimensional Lennard-Jones system under different conditions of temperature () and particle concentration () has been studied using the Monte-Carlo method with the introduction of real thermal motion of the constituent particles through a modification of the conventional Metropolis algorithm. The - phase diagram determined from the study of the root mean square displacement of the particles shows features characteristics of the - diagram for phase equilibrium in real systems. The solid-like to liquid-like transition takes place when the average nearest neighbour distance increases by ~1% of the equilibrium value in the low-temperature solid-like configuration. The Lindemann parameter () is found to decrease with the increase of to reach a steady value of for .