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69 results on '"Srinatha, N."'

55. The effect of co-dopants (Cu3+, Sm3+-ions) on the optical properties of Sodium-Zinc-Borate glasses

Author

S. Hemalatha, M. Nagaraja, Madhu A., Vinayak Pattar K, K. Suresh, and Srinatha N

Abstract

In this article, we describe the synthesis and optical characteristics of (Cu2+, Sm3+-ions) doped sodium zinc borate glasses made using the conventional melt quenching technique. The produced glasses were investigated using XRD, UV-Visible-NIR, and Photoluminescence spectroscopy. XRD analysis reveals the amorphous nature of produced glass samples. The presence of both Cu2+ and Sm3+ ions may be seen in UV-Visible-NIR absorption spectra in the 200-2000 nm range. Refractive index, density, and energy band gaps were all examined as physical and optical variables.In addition, photoluminescence emission spectra for two excitation wavelengths, 290 nm and 400 nm, were obtained to confirm Cu2+ and Sm3+-ions-induced photoluminescence in sodium zinc borate glasses, respectively. When using a 290 nm excitation, the spectra exhibited one wide emission peak about 460 nm, however when using a 400 nm excitation, the spectra revealed three separate peaks in the visible region.The spectral properties of all of the samples were identical. The drop in PL intensity with Sm3+ concentration might be attributed to energy transfer between copper and samarium ions with 400 nm excitation. Surprisingly, the glass sample with 1 mol% Sm3+ exhibits the highest visible PL intensity / emission. The investigation’s findings show that the produced samples are viable candidates for photonic and LED applications.

Published
2022
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58. Effect of immersion liquids on physical properties of Pr3+-ions doped lithium zinc borate glasses

Author

Uthayakumar, T, Yaduvanshi, Namrata, Madhu, A, and Srinatha, N

Abstract

Our research focused on the creation of lithium zinc borate glasses that were doped with Pr3+ions. Specifically, our study focused on the effects of substituting lithium with Pr2O3. Our x-ray diffractometer analysis indicated that the glasses were amorphous, which was as expected. We have also evaluated the impact of adding Pr2O3using toluene and xylene immersion liquids, and we found that these liquids had unique effects on the glass properties. Furthermore, we examined density changes using the Archimedes principle and estimated physical parameters. We carefully analysed the variations in NBO that were caused by Pr2O3, and our results provide valuable insights into the structural behaviour of these glasses.

Published
2024
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64. Transparent, crystalline ZnO thin films: Effect of spin coating parameters on the structural and optical properties.

Author

Raghu, P., Srinatha, N., Mahesh, H. M., Angadi, Basavaraj, Shekhawat, Manoj Singh, Bhardwaj, Sudhir, and Suthar, Bhuvneshwer

Subjects
*THIN films, *SPIN coating, *ZINC oxide films, *OPTICAL properties, *SCANNING electron microscopy
Abstract

In the present investigation, the deposition process was optimized to prepare the thin films of pure ZnO using spin coating technique. The prepared films were characterized through XRD, scanning electron microscopy (SEM) and UV-Visible spectrometer. The parameters such as molar concentration (sol-gel concentration), number of coating (spins) and chuck rotation speed (spin rate) on the structural and optical properties of pure ZnO were investigated. It was found that, thin films prepared with 0.8 M, 10 spin and 3000 rpm speed show good transmittance and crystallinity under optimum laboratory conditions. The microstructure of the films prepared under optimum conditions show the distribution of small uniform grains and thickness (550 nm) throughout the film, confirming the good adhesiveness of the film to the glass substrate. [ABSTRACT FROM AUTHOR]

Published
2018
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67. Spin-coated Al-doped ZnO thin films for optical applications: Structural, micro-structural, optical and luminescence studies.

Author

Angadi, Basavaraj, Srinatha, N., Raghu, P., and Mahesh, H.M.

Subjects
*ZINC oxide thin films, *PHOTOLUMINESCENCE, *SOL-gel processes, *DOPING agents (Chemistry), *LIGHT emitting diodes, *PHOTONIC band gap structures, *SPINTRONICS
Abstract

Zn 1−x Al x O (x = 0, 0.01, 0.02, 0.03) thin films were deposited on glass substrate using sol-gel spin coating method and the effect of Al doping on their structural, micro-structural, optical and photoluminescence properties were investigated. The XRD results confirm the single phase nature and the successful substitution of Al at Zn site in ZnO thin films. Further with Al doping, the crystallite size, lattice parameters and film thickness were found to decrease. Also, both AFM and SEM results confirm the formation of spherical grains with lower roughness of the films. Al doped (>2%) films shows ∼ 90% transparency in the visible wavelength region. Widening of band gap (3.18–3.34 eV) was observed with increase in Al doping concentration, which was attributed to the Burstein–Moss band-filling effect. The defect induced luminescence at room temperature was studied by photoluminescence spectroscopy. PL spectra of AZO films show sharp peaks in the visible wavelength region. A detailed analysis of photoluminescence of undoped and Al doped ZnO films indicates the inhibition of defect density of electronic states due to substitution of Al 3+ . The observed emission peaks were attributed to the defect related deep-level emissions. Results suggest possible use of Al doped ZnO films for transparent conducting oxide (TCO) electrodes and light emitting diodes (LED's) applications. [ABSTRACT FROM AUTHOR]

Published
2017
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69. New fuel governed combustion synthesis and improved luminescence in nanocrystalline Cr3+doped ZnAl2O4particles

Author

Srinatha, N., Satyanarayana Reddy, S., Suriyamurthy, N., Rudresh Kumar, K.J., Suresh Kumar, M.R., Madhu, A., and Angadi, Basavaraj

Abstract

•Nanocrystalline, single phased Cr3+doped ZnAl2O4prepared via SCS method using Leucine (new fuel).•The interaction of Cr3+and ZnAl2O4host matrix, and effect Cr3+on structural, optical, and luminescence properties are investigated.•Increases in Cr3+concentration result in PL emission enhancement up to x = 0.07.•Racah parameters, crystal field parameters, and local site symmetry of Cr3+ion are estimated.•The value of Dq/B was 3.02, confirms the occupancy of Cr3+ions in a strong crystal field.

Published
2022
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