Faculty Publications
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Item Highly transparent and conducting ITO/Ag/ITO multilayer thin films on FEP substrates for flexible electronics applications(Elsevier B.V., 2017) Sibin, K.P.; Srinivas, G.; Shashikala, H.D.; Dey, A.; Sridhara, N.; Sharma, A.K.; Barshilia, H.C.Transparent and conducting ITO/Ag/ITO (IAI) multilayer coatings were deposited on glass and flexible fluorinated ethylene propylene (FEP) substrates by reactive sputtering using metallic In:Sn (90%:10%) and Ag targets at room temperature. Middle Ag layer thickness was optimized to obtain maximum figure of merit (?) and the optimum Ag layer thickness was found to be ~13 nm. The optimized IAI multilayer on glass substrate showed transmittance of ~88.6% and sheet resistance of ~7.1 ?/sq. The transmittance increased to ~91.4% for the IAI multilayer deposited on one side etched glass. The optimized IAI multilayer coating was also deposited on flexible FEP substrates. The electrical, optical, structural and morphological properties of IAI deposited on glass and FEP substrates were compared. IAI deposited on FEP substrate showed transmittance of ~90.2% at ? = 550 nm, sheet resistance of ~6.9 ?/sq. and figure of merit of ~52 × 10?3 ??1. Bending test of IAI deposited FEP proved the high flexibility of IAI multilayer for the flexible transparent electrode applications. Solar selectivity study of IAI on FEP substrate showed it can effectively reflect the higher wavelength region of solar spectrum and can be used as a flexible solar spectrum segregator. Optical haze measurements of IAI coated glass and FEP show that high haze value can be achieved by increasing the roughness on non-coated side of the FEP substrate. © 2017Item Pyrene-based chalcones as functional materials for organic electronics application(Elsevier Ltd, 2023) Kagatikar, S.; Dhanya, D.; Kekuda, D.; Satyanarayana, M.N.; Kulkarni, S.D.; Sudhakar, Y.N.; Vatti, A.K.; Sadhanala, A.Though new generation organic electronic devices have evolved from mere scientific perceptions to real-life marketed applications, considerably less research attention has been focused on n-type or electron transporting small molecule semiconductors. The present study is focused on the exploration of structural, thermal, electrochemical, electrical, and optical properties of two pyrene-based chalcones: PC1 and PC2, synthesized through Claisen Schmidt condensation reaction. The chalcones displayed good thermal stability and wide bandgap n-type semiconducting behaviour with high charge carrier concentration and dielectric constant. The experimental evidences including fluorescence measurements, nanoaggregate size, and morphology analysis, supported by DFT calculations and molecular dynamic simulations advocated the intramolecular charge transfer and aggregation-induced enhanced emission features of the molecules. Successful fabrication of a diode in combination with the current-voltage characteristics established the candidature of PC1 and PC2 for electro-optical devices. The dielectric studies were performed to measure dielectric constant and AC conductivity at different frequency ranges. The cyclic voltammetry and AC impedance response of PC2 differed from PC1 due to the inclusion of a fluorine atom in the molecular scaffold. Further, the functional implication of PC2 as an electrode material was explored by constructing a supercapacitor, which offered a specific capacitance of 220 Fg-1 at a scan rate of 10 mV s−1. Moreover, these chalcone-based organic semiconductors displayed high thermal and charge carrier concentration as well as compatibility with other layers in an OLED device. Hence PC1/PC2 can be further investigated as dopants along with other emissive layers as host materials in OLEDs. © 2022 Elsevier B.V.Item Investigation of Indium doped Se-Te bulk chalcogenide glasses for electrical switching and phase changing applications(Elsevier Ltd, 2024) Joshi, S.; Rodney, J.D.; James, A.; Behera, P.K.; Udayashankar, N.K.Recently, Metal-doped Se-Te chalcogenides have gained a lot of interest due to their unique capacity for electrical switching, which makes them desirable for electronic applications. This study examines the electrical switching characteristics of bulk Se86−xTe14Inx (0 ≤ x ≤ 6) amorphous alloys produced by the conventional melt-mix-quench process. The samples with an Indium atomic percentage between 2 to 6 exhibited a remarkable transition from a highly resistive to a low resistive state when subjected to an electric field with a current of 1 mA, displaying quick and reversible switching behaviour. The threshold voltage (Vth) significantly dropped from 410.6 V to 49.2 V with an increase in Indium concentration. Additionally, above the specific current threshold, these bulk glasses demonstrated memory-type switching, demonstrating their potential for data storage applications. To comprehend the trend of glass forming ability, thermal stability range and Hruby's glass stability parameters, with their compositional dependency, Differential Scanning Calorimetry (DSC) was utilized. The sample Se80Te14In6 emerged to be the fastest phase-changing material, with a memory switching current threshold of Ith = 1.3 mA and a threshold voltage value of 49.2 V. To study the formation of crystallites in Se-Te-In alloy, X-ray diffraction patterns of pristine glass and the annealed sample were examined. Furthermore, temperature-dependent conductivity investigations showed a sharp rise in conductivity once the process crystallization begins (Tx), and also the threshold voltage (Vth) of the samples decreased linearly with rising temperature. Overall, this study provides valuable insights into the electrical switching behaviour and thermal properties of Se-Te-In chalcogenide glasses, enhancing their suitability in electronic devices. © 2024 Elsevier B.V.Item Synthesis of ZnO and CuO–ZnO nanocomposites for photo-conducting and dielectric applications(Elsevier Ltd, 2024) Advaitha, M.; Mahendra, K.; Pattar, J.; Das, P.P.Zinc oxide (ZnO) and its composites has garnered a tremendous attention lately due to its effective role in electronic and optoelectronic applications. The present manuscript reports the synthesis and characterization of ZnO and CuO–ZnO nanocomposites. These samples were synthesized using precipitation technique and studied for voltage-dependent dielectrics and photoconductivity properties. Structural properties were thoroughly investigated using powder X-ray diffraction (PXRD) measurements. The composite material revealed decreased crystallinity and increased strain in the material. Optical absorption measurements were recorded using UV–vis diffusion reflectance measurements and the changes in the absorbance spectrum corresponding bandgap is explored. The obtained band gap is comparatively less for the composite material when compared with prestine ZnO. Structural morphology of the synthesized materials was observed and compared and changes in the composites when compared with the ZnO. Drastic changes in the morphology is witnessed. Electrical response of these synthesized semiconductors was studied using I–V and dielectric measurements. CuO–ZnO samples show a very clear sensitivity to the voltage dependent dielectric properties compared to ZnO. The composite and ZnO are studied using I–V measurements and the light dependent I–V measurements and composite revealed photo sensitivity. Drastic change in the conductivity is witnessed inferring the material to be used in optoelectronic application. Dielectric, Impedance, dielectric loss, AC conductivity and modulus index of the materials were explored by subjecting the materials to impedance measurements. The materials were also explored with different voltages and compared. The composite material revealed drastic variations for change in the voltage and measured parameters were compared with the ZnO. © 2024Item Investigation of Performance Improvement in Drain Extended Longitudinal FinFETs for Thermal-aware Sustainable Electronics Applications(Springer Science and Business Media B.V., 2025) Nanjunda, A.; Nikhil, K.S.This work presents a comprehensive investigation of GaN-based Junctionless Drain Extended Longitudinal FinFET (DELFinFET) using Sentaurus TCAD simulations, targeting thermally robust and energy efficient semiconductor devices as a means to reduce the environmental footprint of electronic devices. Introducing a longitudinal fin achieves superior lateral electric field modulation, improved carrier transport, and enhanced electric control. This helps in improving the key analog performance metrics such as sub-threshold slope, leakage current (Ioff), transconductance (gm), and the switching ratio (Ion/Ioff). The results obtained highlight the potential of DELFinFET for low-power applications. A comparative evaluation is performed between the designed device and other device configurations to verify the effectiveness of the design. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.Item Influence of titanium redox states on luminescence and conductivity in TiO2 -doped borophosphate glass system(Elsevier B.V., 2025) Rashmi, R.; Ingle, A.; Raghuvanshi, V.; Shashikala, H.D.; Nagaraja, H.S.Borophosphate glasses have garnered significant interest due to their potential for optical and electronic applications. This research delves into the luminescent and conductive properties of 40P2O5–25B2O3-(35-x) BaO-xTiO2 (x = 0–5 mol%) glasses synthesized via the melt-quench method. The glass doped with 4 mol% TiO2 exhibited intense luminescence within the 400–600 nm spectrum, manifesting as a vivid blue emission and the highest Ti3+ ion concentration. Beyond this threshold, the luminescence intensity waned, highlighting the significance of Ti4+/Ti3+ ratios. Absorption spectra and X-ray photoelectron spectroscopy were utilized to study these multivalent ions. Temperature-dependent AC conductivity, exhibited a linear increase, consistent with the Correlated Barrier Hopping (CBH) model. Enhanced polaron hopping between Ti3+ and Ti4+ with increasing TiO2 content improved the dielectric constant and conductivity, peaking at 4.145×10?5 Scm?1 at 5 mol% TiO2 within the 450–530 °C range. These findings underscore the tunability of TiO2-doped glasses for optoelectronic applications. © 2024 Elsevier B.V.