Browsing by Author "Murari, M.S."

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Improvement of third-order NLO properties of vacuum deposited Cd1-xPbxS nanostructured thin films for optoelectronic device applications
(Elsevier Ltd, 2023) Bairy, R.; Vijeth, H.; Kulkarni, S.D.; Murari, M.S.; Bhat K, U.K.
A polycrystalline nanostructured cadmium lead sulfide thin film was deposited using the thermal evaporation (PVD) technique (Cd1-xPbxS with x = 0.00, 0.01, 0.05 and 0.1 wt.% of Pb). Structural parameters of as-prepared Cd1-xPbxS thin films have been studied through X-ray diffraction. The optical investigation demonstrates that Cd1-xPbxS film's optical band gap (Eg) may be adjusted from the visible to the near-infrared region. (2.64 - 2.42 eV). The film is substantially more appropriate for absorbing layers in solar cells and optoelectronic applications due to the large decrease in ‘Eg.’ The enhanced Pb doping was found to have altered the surface morphology, verified by Field Emission Scanning Electron Microscopy (FESEM) images. The doped films also showed a significant red shift in the band edge and increased transmittance in the visible and NIR regions. The third-order nonlinear optical (TONLO) parameters of the samples were determined from the Q-switched Nd: YAG laser with 65-ps pulse duration at 1064 nm. The investigated TONLO components such as nonlinear absorption coefficient (β), nonlinear refractive index (n2) and the susceptibility χ(3)were found to be in the range from 1.16 × 10−3 to 4.12 × 10−3 (cmW−1), 1.06 × 10−8 to 3.32 × 10−8 (cm2 W−1) and 1.23 × 10−4 to 5.62 × 10−4 (esu) respectively. The results indicate that Pb-doping on CdS nanostructures on surface morphology can be used to modify NLO characteristics.Cd1-xPbxS thin film is a potential and able material for optoelectronic device applications, as seen by these encouraging NLO results. © 2023 Elsevier Ltd
The role of cobalt doping in tuning the band gap, surface morphology and third-order optical nonlinearities of ZnO nanostructures for NLO device applications
(2019) Bairy, R.; Patil, P.S.; Maidur, S.R.; Vijeth, H.; Murari, M.S.; Bhat, U.K.
The work presented here reported the effect of doping cobalt (Co) in ZnO thin films. The thin films were prepared using the spray pyrolysis technique with 0, 1, 5 and 10 wt% cobalt doping concentrations to study the morphological, optical and third-order nonlinear optical (NLO) properties. X-ray diffraction revealed the crystalline nature of the prepared thin films, and the crystallite size was found to increase with the concentration of doped Co. The morphology and surface topography of the films were largely influenced by doping, as indicated by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). With an increase in Co-doping concentration, the direct optical energy band-gap value increased from 3.21 eV to 3.45 eV for pure to 10 at% of Co concentrations respectively. To study the NLO properties of the prepared thin films, the Z-scan technique was adopted; it was observed that with an increase in the doping concentration from 0 to 10 wt%, the nonlinear absorption coefficient (?) was enhanced from 4.68 10-3 to 9.92 10-3 (cm W-1), the nonlinear refractive index (n2) increased from 1.37 10-8 to 2.90 10-8 (cm2 W-1), and the third-order NLO susceptibility (?(3)) values also increased from 0.79 10-6 to 1.88 10-6 (esu). At the experimental wavelength, the optical limiting (OL) features of the prepared films were explored, and the limiting thresholds were calculated. The encouraging results of the NLO studies suggest that the Co:ZnO thin film is a capable and promising material for nonlinear optical devices and optical power limiting applications. 2019 The Royal Society of Chemistry.
TeO2 for enhancing structural, mechanical, optical, gamma and neutron radiation shielding performance of bismuth borosilicate glasses
(Elsevier Ltd, 2023) D'Souza, A.N.; Padasale, B.; Murari, M.S.; Karunakara, N.; Sayyed, M.I.; Elsafi, M.; Al-Ghamdi, H.; Almuqrin, A.H.; Kamath, S.D.
The synthesized 12Bi2O3– 8BaO–12ZnO-0.5CeO2-17.5SiO2- (50-x) B2O3- xTeO2 glasses with x = 0, 10, 20, 30 and 40 mol% (coded BiTe-0 to BiTe-40) were investigated in terms of physical, structural, optical and mechanical properties to examine the influence of CeO2 and TeO2 on the heavy metal oxide (HMO) borosilicate network. Density values increased continuously with increasing TeO2 concentration with BiTe-40 glass exhibiting maximum value of 5.0875 gcm−3. This property helped in enhancement of refractive index values from 1.769 for BiTe-0 to 1.942 for BiTe-40. Fourier transform infrared (FTIR) analysis of studied glasses revealed the presence of additional small peak at 683 cm−1 in BiTe-30 and BiTe-40 which confirmed the formation of stable TeO4 units in the glass network. The deep brown colour of the glass existing due to bismuth's presence was nullified by CeO2 and TeO2 additives which improved transparency of the glass. Urbach analysis of these glasses led to optical bandgap variation between 3.27 eV and 2.73 eV for 0–40 mol% TeO2 concentration. Makishima and Mackenzie model was utilized for evaluation of elastic property of the glasses, and Poisson's ratio ranging between 1.935 and 1.953 was obtained. Vickers micro-indentation test on the current glasses revealed decreasing microhardness from 4.116 to 4.076 GPa with TeO2 variation from 0 to 40 mol% at 9.8 N load. Gamma radiation shielding parameters were determined using Phy-X/PSD software and it was found that BiTe-40 glass produce maximum MAC (mass attenuation co-efficient) values in high photon energy region 3.5–15 MeV. The present article also contains a detailed emphasis on behaviour of gamma radiation build-up factors at different incident photon energy and TeO2 concentration. The increasing trend of exposure build up factor (EBF) was seen with increasing penetration depth inside the samples at all energies, indicating that glasses of larger thickness improve the escape probability of photons. Meanwhile, fast neutron removal cross-section (FNRCS) was highest for BiTe-10 sample (0.10118 cm−1) which also surpassed the value of ordinary concrete (0.093 cm−1). Overall, the present glass system bested other conventional shields available commercially in terms of gamma and neutron radiation shielding effectiveness. © 2022 Elsevier B.V.
The role of cobalt doping in tuning the band gap, surface morphology and third-order optical nonlinearities of ZnO nanostructures for NLO device applications
(Royal Society of Chemistry, 2019) Bairy, R.; Patil, P.S.; Maidur, S.R.; Vijeth, H.; Murari, M.S.; Bhat K, U.K.
The work presented here reported the effect of doping cobalt (Co) in ZnO thin films. The thin films were prepared using the spray pyrolysis technique with 0, 1, 5 and 10 wt% cobalt doping concentrations to study the morphological, optical and third-order nonlinear optical (NLO) properties. X-ray diffraction revealed the crystalline nature of the prepared thin films, and the crystallite size was found to increase with the concentration of doped Co. The morphology and surface topography of the films were largely influenced by doping, as indicated by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). With an increase in Co-doping concentration, the direct optical energy band-gap value increased from 3.21 eV to 3.45 eV for pure to 10 at% of Co concentrations respectively. To study the NLO properties of the prepared thin films, the Z-scan technique was adopted; it was observed that with an increase in the doping concentration from 0 to 10 wt%, the nonlinear absorption coefficient (?) was enhanced from 4.68 × 10-3 to 9.92 × 10-3 (cm W-1), the nonlinear refractive index (n2) increased from 1.37 × 10-8 to 2.90 × 10-8 (cm2 W-1), and the third-order NLO susceptibility (?(3)) values also increased from 0.79 × 10-6 to 1.88 × 10-6 (esu). At the experimental wavelength, the optical limiting (OL) features of the prepared films were explored, and the limiting thresholds were calculated. The encouraging results of the NLO studies suggest that the Co:ZnO thin film is a capable and promising material for nonlinear optical devices and optical power limiting applications. © 2019 The Royal Society of Chemistry.