Hari Prasad Kamatam | Institute Of Aeronautical Engineering (original) (raw)

Papers by Hari Prasad Kamatam

Applied Physics B, 2021

In this work, a facile spray-assisted perfume atomizer technique was used to prepare CdO and Fe-d... more In this work, a facile spray-assisted perfume atomizer technique was used to prepare CdO and Fe-doped CdO (CdO:Fe) thin films with varying concentrations of Fe (1, 3, and 5 wt%). The deposited films were characterized using different analytical techniques to realize the structural, morphological, optical, electrical, and photosensing properties. From X-ray diffraction (XRD) results, the CdO and CdO:Fe thin films have a cubic structure and an increase in crystallite size was observed for the CdO:Fe(3%) sample. The optical studies of the doped samples reveal a high absorption in the observed wavelength range and a decrease in optical bandgap values. The CdO:Fe(3%) sample exhibits a minimum resistivity value (4.02 × 10–3 Ωcm), high carrier concentration (22.92 × 1019 cm−3), and high mobility (6.78 cmV−1 s−1). The current–voltage characteristics suggest that the CdO:Fe(3%) sample has a lower ideality factor of 4.2, high photocurrent value of 1.62 × 10–2 A. It also has better photosensing parameter values such as responsivity of 0.15AW−1, the external quantum efficiency of 2.92 × 108 Jones, and detectivity of 50%, which are due to the synergistic effect of increased crystallite size, high light absorption, optimum bandgap, and better electrical properties of the CdO:Fe(3%) sample.

Spinel LiMn2O4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temp... more Spinel LiMn2O4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering method. All the grown thin films were post-annealed up to 500 C, in the presence of oxygen to enrich the crystallinity of the thin film. XRD and Raman results showed the formation of the cubic spinel structured LMO thin film annealed at 500 C. AFM micrographs of LMO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and postannealed LMO thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) sub... more Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) substrate at ambient temperature by RF magnetron sputtering method. The asgrown LATP thin film was post-annealed up to 500 C in the presence of oxygen to enrich the crystallinity of the thin film. XRD results confirm the formation of the crystalline phase of the LATP thin film annealed at 500 C. AFM micrographs of LATP thin films revealed the surface morphology and roughness properties. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and post-annealed LATP thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Layered LiCoO2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at ambi... more Layered LiCoO2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering. All the prepared thin films were annealed at 400, 500 and 600 C under oxygen atmosphere to enhance the crystallinity. X-ray diffraction pattern of the LCO thin film annealed at 600 C showed the formation of pure rhombohedral phase. AFM micrographs of LCO thin films reveal the surface morphology and roughness modifications parameters. Impedance measurements were made as a function temperature in the frequency range of 100 Hz to 10 MHz for all the prepared LCO thin films From the analysis of the Impedance, ac conductivity and dielectric constant (ε′) for the as-deposited and post-annealed LCO thin films were evaluated as a function temperature in the frequency range of 100 Hz to 10 MHz.

Li4Ti5O12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) substra... more Li4Ti5O12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) substrate by using RF magnetron sputtering method. All the deposited thin-films were annealed at three different temperatures 400, 500 and 600 C under an oxygen atmosphere to enhance the crystallinity. X-ray diffraction patterns showed the formation of cubic spinel structure phase of LTO thin film annealed at 600 C. AFM micrographs for LTO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′) and electric modulus (M'') for the as-deposited and post-annealed LTO thin films were evaluated by analyzing the measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate... more Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate by pulsed laser deposition technique under different oxygen partial pressures (from 50 mTorr to 300 mTorr) by keeping the substrate temperature at 500 C. X-ray diffraction pattern of the LNMCO thin film annealed under 300 mTorr showed the formation of pure rhombohedral phase. AFM micrographs of LNMCO thin films reveal the surface morphology and roughness. The measured impedance data of all the prepared LNMCO thin films grown under different oxygen partial pressures were analyzed using the win fit software and evaluated the ac conductivity, dielectric constant (ε′) and electric modulus as a function as a function of frequency. From the observed results, the developed LNMCO thin film grown under 300 mTorr can be a better cathode material for developing all-solid-state rechargeable lithium-ion micro-batteries.

Journal of Inorganic and Organometallic Polymers and Materials, 2021

The magnesium oxide (MgO) nanoparticles (NPs) were prepared using the sol–gel method and the prep... more The magnesium oxide (MgO) nanoparticles (NPs) were prepared using the sol–gel method and the prepared nanoparticles were annealed at different temperatures (500, 600, and 700 °C). The prepared nanoparticles were characterized using X-ray diffraction (XRD) for the structural analysis (Rietveld refinement), SEM for surface morphological analysis, and the energy dispersive X-ray analysis for elemental compositional analysis. The detailed structural analyses proved the expansion of the unit cell by increasing the annealing temperature. The detailed electronic bonding behavior and the expansion of the unit cell of the prepared nanoparticles were analyzed and reported using the maximum entropy method (MEM). The light absorption behavior of the MgO was probed using UV–Vis-NIR spectroscopic analysis. The photocatalytic decomposition capabilities of the synthesized MgO nanoparticles were studied against a model pollutant such as methylene blue dye. The maximum photocatalytic efficiency of 92% in 150 min was observed for MgO nanoparticles annealed at 700 °C.

Sensors and Actuators A: Physical, 2021

Abstract In this communication, we report on how the co-doping of two transition metal ions (Fe a... more Abstract In this communication, we report on how the co-doping of two transition metal ions (Fe and Mn) effectively improves the structural, morphological, optical, electrical and photodetection properties of CdO thin films than individual doping. For this, pure-CdO, Fe-doped, Mn-doped and (Fe-Mn) co-doped CdO thin films are deposited by spray pyrolysis technique. X-ray diffraction (XRD) patterns reveal that these films possess cubic structure and belong to the Fm-3 m space group. The Field Emission Scanning Electron micrographs hold a qualitative agreement with the crystalline sizes obtained from the XRD analysis. Energy Dispersive X-Ray Analysis approved the existence of constituent elements in the prepared films. The photoluminescence spectra identified the quality of crystal structure and the presence of defects in the prepared films. Analyzing the absorption spectra unveiled the direct bandgap values in the range 2.32 eV (for pure-CdO) - 1.96 eV (for CdO:Fe(1%):Mn(1%)). The Hall Effect measurements established n-type behavior with the values of resistivity (ρ), carrier concentration (n) and carrier mobility values in the range 5.8–7.1 mΩcm, 6.7−2.4 × 1019 cm−3 and 16−37 cm2/Vs, respectively. Three different transport mechanisms such as ohmic, recombination-tunneling and space-charge limited current are found to play roles in the three distinct ranges of the I–V data measured for the films under study. The ideality factor values are obtained from the region where the recombination-tunneling mechanism is prevalent. The photoelectric parameters such as photo-responsivity, and external quantum efficiency are obtained. The values of these quantities pertaining to pure-CdO, CdO:Mn, CdO:Fe and CdO:Fe:Mn films vary in the range 128.4–561.3 mA/W, and 30–131.1 %, respectively. From the current study, it was found that photoresponsivity and external quantum efficiency are enhanced by a factor of four in codoped CdO films than the undoped CdO film and can find potential photodetector applications.

Journal of Materials Research, 2021

In this work, we have coated 0, 1, 3, and 5 wt% of Erbium (Er)-doped tin oxide (SnO2) films on gl... more In this work, we have coated 0, 1, 3, and 5 wt% of Erbium (Er)-doped tin oxide (SnO2) films on glass using a simple nebulizer spray pyrolysis method to make an ammonia vapor sensor with remarkable sensitivity. X-ray diffraction, Atomic force microscopy, Ultraviolet–visible spectroscopy and photoluminescence methods were employed to inspect the thin-film samples. Room-temperature ammonia vapor sensing was performed by a computer connected to the homemade gas-sensing system. The results obtained show that Er doping in SnO2 films gradually decreased the crystallite size with an increase of the surface area improving the sensing property of the vapor. A minimum optical band gap (i.e., 3.23 eV) is achieved for 5 wt% Er-doped film. The fabricated Er-doped SnO2 gas sensor showed response/recovery time highly dependent on dopant concentration. The Er concentration of 5 wt% doped SnO2 thin film showed maximum sensitivity of 91%, fast response, and recovery time of 29 and 7 s, respectively, due to high surface to volume ratio.

Superlattices and Microstructures, 2021

Abstract In the present study, pure and Al-doped ZnO thin films have been deposited on glass subs... more Abstract In the present study, pure and Al-doped ZnO thin films have been deposited on glass substrates using a cost-effective nebulizer spray technique. The structural, topographical, photoluminescence, and UV detector properties of ZnO thin films have been studied for various aluminium-doping concentrations. X-ray diffraction (XRD) studies confirmed the polycrystalline hexagonal structure plane with preferred orientation along (002) direction. The ZnO structural parameters like crystallite size, dislocation density, and strain showing considerable variation with aluminium doping. Atomic force microscope (AFM) images displaying spherical grains and the grain size is increasing with Al concentration. The energy dispersive X-ray (EDX) analysis displays the presence of Zn, Al, and O elements in the deposited thin films. The optical bandgap values are decreased with aluminium doping concentration and the lowest value was observed for the 1% Al doping. Photoluminescence (PL) spectra reveal a sharp emission peak at 390 nm and peak with the shoulder at 554 nm. The Responsivity, External quantum efficiency, and Detectivity of pure and doped samples are in the range of 0.22–0.38 AW-1, 70–123%, and 1.22 × 1010 to 1.70 × 1010 Jones, respectively. The better photodetection results are observed for the 1% Al-doped ZnO thin film which indicates it is a good candidate for photo-detector applications.

Materials Letters, 2021

Herein, the effect of Terbium (Tb) doping on the photodetection properties of Ag/CdS/Ag devices h... more Herein, the effect of Terbium (Tb) doping on the photodetection properties of Ag/CdS/Ag devices have been elucidated. An enhancement in the photodetector performance was noted for Ag/Tb@CdS/Ag device in terms of amplified sensitivity of 592, improved responsivity of 3.64 A/W, and excellent detectivity of 6.39 × 10 Jones in compared to pure Ag/CdS/Ag device with respective values of 192, 0.24 A/W and 7.98 × 10 Jones. Moreover, the Tb-doped device exhibits a faster response time of 30 ms as compared to 421 ms for device with pure CdS. The enhancement in photodetector performance was explained through the change in conduction mechanism from Schottky in Ag/CdS/Ag to ohmic in Ag/Tb@CdS/Ag device.

Coatings, 2021

Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed l... more Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed laser deposition technique. The obtained In2O3/In2O3:Cr thin films structural, morphological, optical, magnetic and gas sensing properties were briefly investigated. The X-ray diffraction results confirmed that the grown thin films are in single-phase cubic bixbyte structure with space group Ia-3. The SEM analysis showed the formation of agglomerated spherical shape morphology with the decreased average grain size for Cr doped In2O3 thin film compared to pure In2O3 film. It is observed that the Cr doped In2O3 thin film shows the lower band gap energy and that the corresponding transmittance is around 80%. The X-ray photoelectron spectroscopy measurements revealed that the presence of oxygen vacancy in the doped In2O3 film. These oxygen defects could play a significant role to enhance the sensing performance towards chemical species. In the magnetic hysteresis loop, it is clear that the pr...

Advanced Materials - TechConnect Briefs 2017, 2017

Li 4 Ti 5 O 12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) su... more Li 4 Ti 5 O 12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) substrate by using RF magnetron sputtering method. All the deposited thin-films were annealed at three different temperatures 400, 500 and 600 o C under an oxygen atmosphere to enhance the crystallinity. X-ray diffraction patterns showed the formation of cubic spinel structure phase of LTO thin film annealed at 600 o C. AFM micrographs for LTO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′) and electric modulus (M'') for the as-deposited and postannealed LTO thin films were evaluated by analyzing the measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Advanced Materials - TechConnect Briefs 2017, 2017

Layered LiCoO 2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at amb... more Layered LiCoO 2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering. All the prepared thin films were annealed at 400, 500 and 600 o C under oxygen atmosphere to enhance the crystallinity. X-ray diffraction pattern of the LCO thin film annealed at 600 o C showed the formation of pure rhombohedral phase. AFM micrographs of LCO thin films reveal the surface morphology and roughness modifications parameters. Impedance measurements were made as a function temperature in the frequency range of 100 Hz to 10 MHz for all the prepared LCO thin films. From the analysis of the Impedance, ac conductivity and dielectric constant (ε′) for the as-deposited and post-annealed LCO thin films were evaluated as a function temperature in the frequency range of 100 Hz to 10 MHz.

Advanced Materials - TechConnect Briefs 2017, 2017

Spinel LiMn 2 O 4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient t... more Spinel LiMn 2 O 4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering method. All the grown thin films were post-annealed up to 500 o C, in the presence of oxygen to enrich the crystallinity of the thin film. XRD and Raman results showed the formation of the cubic spinel structured LMO thin film annealed at 500 o C. AFM micrographs of LMO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and post-annealed LMO thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

TechConnect Briefs 2018 - Advanced Materials, 2018

Spinel Li4Ti5O12 (LTO) thin films were deposited on Ti/Si (100) substrate by an RF magnetron sput... more Spinel Li4Ti5O12 (LTO) thin films were deposited on Ti/Si (100) substrate by an RF magnetron sputtering method at ambient temperature and followed by annealing at 400, 500 and 600 o C under an oxygen atmosphere. The observed X-ray diffraction pattern of annealed at 600 o C LTO thin film showed the formation of cubic spinel phase. AFM micrographs of LTO thin films reveal their surface morphology and roughness. The conductivity of annealed at 600 o C LTO thin film is evaluated by analyzing the measured impedance data using the win fit software and it is found to be 5.47×10 S cm. The ac conductivity of the as-deposited and post-annealed LTO thin films was evaluated using the measured impedance data as a function of temperature and frequency (100 Hz to 10 MHz) and it is found to increase with a rise of annealing temperatures. Hence, the observed results of the developed annealed LTO thin film at 600 o C can be a better anode material for developing all-solid-state rechargeable high energy density lithium-ion micro-batteries.

TechConnect Briefs 2018 - Advanced Materials, 2018

Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate... more Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate by pulsed laser deposition technique under different oxygen partial pressures (from 50 mTorr to 300 mTorr) by keeping the substrate temperature at 500 o C. X-ray diffraction pattern of the LNMCO thin film annealed under 300 mTorr showed the formation of pure rhombohedral phase. AFM micrographs of LNMCO thin films reveal the surface morphology and roughness. The measured impedance data of all the prepared LNMCO thin films grown under different oxygen partial pressures were analyzed using the win fit software and evaluated the ac conductivity, dielectric constant (ε′) and electric modulus as a function as a function of frequency. From the observed results, the developed LNMCO thin film grown under 300 mTorr can be a better cathode material for developing all-solid-state rechargeable lithium-ion micro-batteries.

TechConnect Briefs 2018 - Advanced Materials, 2018

Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) sub... more Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) substrate at ambient temperature by RF magnetron sputtering method. The asgrown LATP thin film was post-annealed up to 500 o C in the presence of oxygen to enrich the crystallinity of the thin film. XRD results confirm the formation of the crystalline phase of the LATP thin film annealed at 500 o C. AFM micrographs of LATP thin films revealed the surface morphology and roughness properties. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and post-annealed LATP thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Coatings, 2021

Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed l... more Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed laser deposition technique. The obtained In2O3/In2O3:Cr thin films structural, morphological, optical, magnetic and gas sensing properties were briefly investigated. The X-ray diffraction results confirmed that the grown thin films are in single-phase cubic bixbyte structure with space group Ia-3. The SEM analysis showed the formation of agglomerated spherical shape morphology with the decreased average grain size for Cr doped In2O3thin film compared to pure In2O3film. It is observed that the Cr doped In2O3thin film shows the lower band gap energy and that the corresponding transmittance is around 80%. The X-ray photoelectron spectroscopy measurements revealed that the presence of oxygen vacancy in the doped In2O3film. These oxygen defects could play a significant role to enhance the sensing performance towards chemical species. In the magnetic hysteresis loop, it is clear that the prepared films confirm the ferromagnetic behaviour and the maximum saturation value of 39 emu/cc for Cr doped In2O3 film. NH3 gas sensing studies was also carried out at room temperature for both pure and Cr doped In2O3films, and the obtained higher sensitivity is 182% for Cr doped In2O3, which is about nine times higher than for the pure In2O3 film due to the presence of defects on the doped film surface.

Sensors and Actuators A: Physical, 2021

In this communication, we report on how the co-doping of two transition metal ions (Fe and Mn) ef... more In this communication, we report on how the co-doping of two transition metal ions (Fe and Mn) effectively improves the structural, morphological, optical, electrical and photodetection properties of CdO thin films than individual doping. For this, pure-CdO, Fe-doped, Mn-doped and (Fe-Mn) co-doped CdO thin films are deposited by spray pyrolysis technique. X-ray diffraction (XRD) patterns reveal that these films possess cubic structure and belong to the Fm-3 m space group. The Field Emission Scanning Electron micrographs hold a qualitative agreement with the crystalline sizes obtained from the XRD analysis. Energy Dispersive X-Ray Analysis approved the existence of constituent elements in the prepared films. The photoluminescence spectra identified the quality of crystal structure and the presence of defects in the prepared films. Analyzing the absorption spectra unveiled the direct bandgap values in the range 2.32 eV (for pure-CdO)-1.96 eV (for CdO:Fe(1%):Mn(1%)). The Hall Effect measurements established n-type behavior with the values of resistivity (), carrier concentration (n) and carrier mobility values in the range 5.8-7.1 m cm, 6.7−2.4 × 10 19 cm −3 and 16−37 cm 2 /Vs, respectively. Three different transport mechanisms such as ohmic, recombination-tunneling and space-charge limited current are found to play roles in the three distinct ranges of the I-V data measured for the films under study. The ideality factor values are obtained from the region where the recombination-tunneling mechanism is prevalent. The photoelectric parameters such as photo-responsivity, and external quantum efficiency are obtained. The values of these quantities pertaining to pure-CdO, CdO:Mn, CdO:Fe and CdO:Fe:Mn films vary in the range 128.4-561.3 mA/W, and 30-131.1 %, respectively. From the current study, it was found that photoresponsivity and external quantum efficiency are enhanced by a factor of four in codoped CdO films than the undoped CdO film and can find potential photodetector applications.

Applied Physics B, 2021

In this work, a facile spray-assisted perfume atomizer technique was used to prepare CdO and Fe-d... more In this work, a facile spray-assisted perfume atomizer technique was used to prepare CdO and Fe-doped CdO (CdO:Fe) thin films with varying concentrations of Fe (1, 3, and 5 wt%). The deposited films were characterized using different analytical techniques to realize the structural, morphological, optical, electrical, and photosensing properties. From X-ray diffraction (XRD) results, the CdO and CdO:Fe thin films have a cubic structure and an increase in crystallite size was observed for the CdO:Fe(3%) sample. The optical studies of the doped samples reveal a high absorption in the observed wavelength range and a decrease in optical bandgap values. The CdO:Fe(3%) sample exhibits a minimum resistivity value (4.02 × 10–3 Ωcm), high carrier concentration (22.92 × 1019 cm−3), and high mobility (6.78 cmV−1 s−1). The current–voltage characteristics suggest that the CdO:Fe(3%) sample has a lower ideality factor of 4.2, high photocurrent value of 1.62 × 10–2 A. It also has better photosensing parameter values such as responsivity of 0.15AW−1, the external quantum efficiency of 2.92 × 108 Jones, and detectivity of 50%, which are due to the synergistic effect of increased crystallite size, high light absorption, optimum bandgap, and better electrical properties of the CdO:Fe(3%) sample.

Spinel LiMn2O4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temp... more Spinel LiMn2O4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering method. All the grown thin films were post-annealed up to 500 C, in the presence of oxygen to enrich the crystallinity of the thin film. XRD and Raman results showed the formation of the cubic spinel structured LMO thin film annealed at 500 C. AFM micrographs of LMO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and postannealed LMO thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) sub... more Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) substrate at ambient temperature by RF magnetron sputtering method. The asgrown LATP thin film was post-annealed up to 500 C in the presence of oxygen to enrich the crystallinity of the thin film. XRD results confirm the formation of the crystalline phase of the LATP thin film annealed at 500 C. AFM micrographs of LATP thin films revealed the surface morphology and roughness properties. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and post-annealed LATP thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Layered LiCoO2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at ambi... more Layered LiCoO2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering. All the prepared thin films were annealed at 400, 500 and 600 C under oxygen atmosphere to enhance the crystallinity. X-ray diffraction pattern of the LCO thin film annealed at 600 C showed the formation of pure rhombohedral phase. AFM micrographs of LCO thin films reveal the surface morphology and roughness modifications parameters. Impedance measurements were made as a function temperature in the frequency range of 100 Hz to 10 MHz for all the prepared LCO thin films From the analysis of the Impedance, ac conductivity and dielectric constant (ε′) for the as-deposited and post-annealed LCO thin films were evaluated as a function temperature in the frequency range of 100 Hz to 10 MHz.

Li4Ti5O12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) substra... more Li4Ti5O12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) substrate by using RF magnetron sputtering method. All the deposited thin-films were annealed at three different temperatures 400, 500 and 600 C under an oxygen atmosphere to enhance the crystallinity. X-ray diffraction patterns showed the formation of cubic spinel structure phase of LTO thin film annealed at 600 C. AFM micrographs for LTO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′) and electric modulus (M'') for the as-deposited and post-annealed LTO thin films were evaluated by analyzing the measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate... more Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate by pulsed laser deposition technique under different oxygen partial pressures (from 50 mTorr to 300 mTorr) by keeping the substrate temperature at 500 C. X-ray diffraction pattern of the LNMCO thin film annealed under 300 mTorr showed the formation of pure rhombohedral phase. AFM micrographs of LNMCO thin films reveal the surface morphology and roughness. The measured impedance data of all the prepared LNMCO thin films grown under different oxygen partial pressures were analyzed using the win fit software and evaluated the ac conductivity, dielectric constant (ε′) and electric modulus as a function as a function of frequency. From the observed results, the developed LNMCO thin film grown under 300 mTorr can be a better cathode material for developing all-solid-state rechargeable lithium-ion micro-batteries.

Journal of Inorganic and Organometallic Polymers and Materials, 2021

The magnesium oxide (MgO) nanoparticles (NPs) were prepared using the sol–gel method and the prep... more The magnesium oxide (MgO) nanoparticles (NPs) were prepared using the sol–gel method and the prepared nanoparticles were annealed at different temperatures (500, 600, and 700 °C). The prepared nanoparticles were characterized using X-ray diffraction (XRD) for the structural analysis (Rietveld refinement), SEM for surface morphological analysis, and the energy dispersive X-ray analysis for elemental compositional analysis. The detailed structural analyses proved the expansion of the unit cell by increasing the annealing temperature. The detailed electronic bonding behavior and the expansion of the unit cell of the prepared nanoparticles were analyzed and reported using the maximum entropy method (MEM). The light absorption behavior of the MgO was probed using UV–Vis-NIR spectroscopic analysis. The photocatalytic decomposition capabilities of the synthesized MgO nanoparticles were studied against a model pollutant such as methylene blue dye. The maximum photocatalytic efficiency of 92% in 150 min was observed for MgO nanoparticles annealed at 700 °C.

Sensors and Actuators A: Physical, 2021

Abstract In this communication, we report on how the co-doping of two transition metal ions (Fe a... more Abstract In this communication, we report on how the co-doping of two transition metal ions (Fe and Mn) effectively improves the structural, morphological, optical, electrical and photodetection properties of CdO thin films than individual doping. For this, pure-CdO, Fe-doped, Mn-doped and (Fe-Mn) co-doped CdO thin films are deposited by spray pyrolysis technique. X-ray diffraction (XRD) patterns reveal that these films possess cubic structure and belong to the Fm-3 m space group. The Field Emission Scanning Electron micrographs hold a qualitative agreement with the crystalline sizes obtained from the XRD analysis. Energy Dispersive X-Ray Analysis approved the existence of constituent elements in the prepared films. The photoluminescence spectra identified the quality of crystal structure and the presence of defects in the prepared films. Analyzing the absorption spectra unveiled the direct bandgap values in the range 2.32 eV (for pure-CdO) - 1.96 eV (for CdO:Fe(1%):Mn(1%)). The Hall Effect measurements established n-type behavior with the values of resistivity (ρ), carrier concentration (n) and carrier mobility values in the range 5.8–7.1 mΩcm, 6.7−2.4 × 1019 cm−3 and 16−37 cm2/Vs, respectively. Three different transport mechanisms such as ohmic, recombination-tunneling and space-charge limited current are found to play roles in the three distinct ranges of the I–V data measured for the films under study. The ideality factor values are obtained from the region where the recombination-tunneling mechanism is prevalent. The photoelectric parameters such as photo-responsivity, and external quantum efficiency are obtained. The values of these quantities pertaining to pure-CdO, CdO:Mn, CdO:Fe and CdO:Fe:Mn films vary in the range 128.4–561.3 mA/W, and 30–131.1 %, respectively. From the current study, it was found that photoresponsivity and external quantum efficiency are enhanced by a factor of four in codoped CdO films than the undoped CdO film and can find potential photodetector applications.

Journal of Materials Research, 2021

In this work, we have coated 0, 1, 3, and 5 wt% of Erbium (Er)-doped tin oxide (SnO2) films on gl... more In this work, we have coated 0, 1, 3, and 5 wt% of Erbium (Er)-doped tin oxide (SnO2) films on glass using a simple nebulizer spray pyrolysis method to make an ammonia vapor sensor with remarkable sensitivity. X-ray diffraction, Atomic force microscopy, Ultraviolet–visible spectroscopy and photoluminescence methods were employed to inspect the thin-film samples. Room-temperature ammonia vapor sensing was performed by a computer connected to the homemade gas-sensing system. The results obtained show that Er doping in SnO2 films gradually decreased the crystallite size with an increase of the surface area improving the sensing property of the vapor. A minimum optical band gap (i.e., 3.23 eV) is achieved for 5 wt% Er-doped film. The fabricated Er-doped SnO2 gas sensor showed response/recovery time highly dependent on dopant concentration. The Er concentration of 5 wt% doped SnO2 thin film showed maximum sensitivity of 91%, fast response, and recovery time of 29 and 7 s, respectively, due to high surface to volume ratio.

Superlattices and Microstructures, 2021

Abstract In the present study, pure and Al-doped ZnO thin films have been deposited on glass subs... more Abstract In the present study, pure and Al-doped ZnO thin films have been deposited on glass substrates using a cost-effective nebulizer spray technique. The structural, topographical, photoluminescence, and UV detector properties of ZnO thin films have been studied for various aluminium-doping concentrations. X-ray diffraction (XRD) studies confirmed the polycrystalline hexagonal structure plane with preferred orientation along (002) direction. The ZnO structural parameters like crystallite size, dislocation density, and strain showing considerable variation with aluminium doping. Atomic force microscope (AFM) images displaying spherical grains and the grain size is increasing with Al concentration. The energy dispersive X-ray (EDX) analysis displays the presence of Zn, Al, and O elements in the deposited thin films. The optical bandgap values are decreased with aluminium doping concentration and the lowest value was observed for the 1% Al doping. Photoluminescence (PL) spectra reveal a sharp emission peak at 390 nm and peak with the shoulder at 554 nm. The Responsivity, External quantum efficiency, and Detectivity of pure and doped samples are in the range of 0.22–0.38 AW-1, 70–123%, and 1.22 × 1010 to 1.70 × 1010 Jones, respectively. The better photodetection results are observed for the 1% Al-doped ZnO thin film which indicates it is a good candidate for photo-detector applications.

Materials Letters, 2021

Herein, the effect of Terbium (Tb) doping on the photodetection properties of Ag/CdS/Ag devices h... more Herein, the effect of Terbium (Tb) doping on the photodetection properties of Ag/CdS/Ag devices have been elucidated. An enhancement in the photodetector performance was noted for Ag/Tb@CdS/Ag device in terms of amplified sensitivity of 592, improved responsivity of 3.64 A/W, and excellent detectivity of 6.39 × 10 Jones in compared to pure Ag/CdS/Ag device with respective values of 192, 0.24 A/W and 7.98 × 10 Jones. Moreover, the Tb-doped device exhibits a faster response time of 30 ms as compared to 421 ms for device with pure CdS. The enhancement in photodetector performance was explained through the change in conduction mechanism from Schottky in Ag/CdS/Ag to ohmic in Ag/Tb@CdS/Ag device.

Coatings, 2021

Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed l... more Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed laser deposition technique. The obtained In2O3/In2O3:Cr thin films structural, morphological, optical, magnetic and gas sensing properties were briefly investigated. The X-ray diffraction results confirmed that the grown thin films are in single-phase cubic bixbyte structure with space group Ia-3. The SEM analysis showed the formation of agglomerated spherical shape morphology with the decreased average grain size for Cr doped In2O3 thin film compared to pure In2O3 film. It is observed that the Cr doped In2O3 thin film shows the lower band gap energy and that the corresponding transmittance is around 80%. The X-ray photoelectron spectroscopy measurements revealed that the presence of oxygen vacancy in the doped In2O3 film. These oxygen defects could play a significant role to enhance the sensing performance towards chemical species. In the magnetic hysteresis loop, it is clear that the pr...

Advanced Materials - TechConnect Briefs 2017, 2017

Li 4 Ti 5 O 12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) su... more Li 4 Ti 5 O 12 (LTO) thin films were deposited at ambient temperature on Ti/silicon (Si) (100) substrate by using RF magnetron sputtering method. All the deposited thin-films were annealed at three different temperatures 400, 500 and 600 o C under an oxygen atmosphere to enhance the crystallinity. X-ray diffraction patterns showed the formation of cubic spinel structure phase of LTO thin film annealed at 600 o C. AFM micrographs for LTO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′) and electric modulus (M'') for the as-deposited and postannealed LTO thin films were evaluated by analyzing the measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Advanced Materials - TechConnect Briefs 2017, 2017

Layered LiCoO 2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at amb... more Layered LiCoO 2 (LCO) cathode thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering. All the prepared thin films were annealed at 400, 500 and 600 o C under oxygen atmosphere to enhance the crystallinity. X-ray diffraction pattern of the LCO thin film annealed at 600 o C showed the formation of pure rhombohedral phase. AFM micrographs of LCO thin films reveal the surface morphology and roughness modifications parameters. Impedance measurements were made as a function temperature in the frequency range of 100 Hz to 10 MHz for all the prepared LCO thin films. From the analysis of the Impedance, ac conductivity and dielectric constant (ε′) for the as-deposited and post-annealed LCO thin films were evaluated as a function temperature in the frequency range of 100 Hz to 10 MHz.

Advanced Materials - TechConnect Briefs 2017, 2017

Spinel LiMn 2 O 4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient t... more Spinel LiMn 2 O 4 (LMO) thin films were deposited on Ti/silicon (Si) (100) substrate at ambient temperature by RF magnetron sputtering method. All the grown thin films were post-annealed up to 500 o C, in the presence of oxygen to enrich the crystallinity of the thin film. XRD and Raman results showed the formation of the cubic spinel structured LMO thin film annealed at 500 o C. AFM micrographs of LMO thin films reveal the surface morphology and roughness modifications. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and post-annealed LMO thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

TechConnect Briefs 2018 - Advanced Materials, 2018

Spinel Li4Ti5O12 (LTO) thin films were deposited on Ti/Si (100) substrate by an RF magnetron sput... more Spinel Li4Ti5O12 (LTO) thin films were deposited on Ti/Si (100) substrate by an RF magnetron sputtering method at ambient temperature and followed by annealing at 400, 500 and 600 o C under an oxygen atmosphere. The observed X-ray diffraction pattern of annealed at 600 o C LTO thin film showed the formation of cubic spinel phase. AFM micrographs of LTO thin films reveal their surface morphology and roughness. The conductivity of annealed at 600 o C LTO thin film is evaluated by analyzing the measured impedance data using the win fit software and it is found to be 5.47×10 S cm. The ac conductivity of the as-deposited and post-annealed LTO thin films was evaluated using the measured impedance data as a function of temperature and frequency (100 Hz to 10 MHz) and it is found to increase with a rise of annealing temperatures. Hence, the observed results of the developed annealed LTO thin film at 600 o C can be a better anode material for developing all-solid-state rechargeable high energy density lithium-ion micro-batteries.

TechConnect Briefs 2018 - Advanced Materials, 2018

Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate... more Layer structured LiNi1/3Co1/3Mn1/3O2 (LNMCO) thin films were grown on the Ti/(Si) (100) substrate by pulsed laser deposition technique under different oxygen partial pressures (from 50 mTorr to 300 mTorr) by keeping the substrate temperature at 500 o C. X-ray diffraction pattern of the LNMCO thin film annealed under 300 mTorr showed the formation of pure rhombohedral phase. AFM micrographs of LNMCO thin films reveal the surface morphology and roughness. The measured impedance data of all the prepared LNMCO thin films grown under different oxygen partial pressures were analyzed using the win fit software and evaluated the ac conductivity, dielectric constant (ε′) and electric modulus as a function as a function of frequency. From the observed results, the developed LNMCO thin film grown under 300 mTorr can be a better cathode material for developing all-solid-state rechargeable lithium-ion micro-batteries.

TechConnect Briefs 2018 - Advanced Materials, 2018

Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) sub... more Li1.3Al0.3Ti1.7 (PO4)3 (LATP) electrolyte thin films were deposited on aluminum oxide (Al2O3) substrate at ambient temperature by RF magnetron sputtering method. The asgrown LATP thin film was post-annealed up to 500 o C in the presence of oxygen to enrich the crystallinity of the thin film. XRD results confirm the formation of the crystalline phase of the LATP thin film annealed at 500 o C. AFM micrographs of LATP thin films revealed the surface morphology and roughness properties. The ac conductivity, dielectric constant (ε′), and electric modulus (M′′) for the as-deposited and post-annealed LATP thin films were evaluated by analyzing measured impedance data as a function temperature in the frequency range of 100 Hz to 10 MHz.

Coatings, 2021

Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed l... more Pure In2O3 and 6% Cr-doped In2O3 thin films were prepared on a silicon (Si) substrate by pulsed laser deposition technique. The obtained In2O3/In2O3:Cr thin films structural, morphological, optical, magnetic and gas sensing properties were briefly investigated. The X-ray diffraction results confirmed that the grown thin films are in single-phase cubic bixbyte structure with space group Ia-3. The SEM analysis showed the formation of agglomerated spherical shape morphology with the decreased average grain size for Cr doped In2O3thin film compared to pure In2O3film. It is observed that the Cr doped In2O3thin film shows the lower band gap energy and that the corresponding transmittance is around 80%. The X-ray photoelectron spectroscopy measurements revealed that the presence of oxygen vacancy in the doped In2O3film. These oxygen defects could play a significant role to enhance the sensing performance towards chemical species. In the magnetic hysteresis loop, it is clear that the prepared films confirm the ferromagnetic behaviour and the maximum saturation value of 39 emu/cc for Cr doped In2O3 film. NH3 gas sensing studies was also carried out at room temperature for both pure and Cr doped In2O3films, and the obtained higher sensitivity is 182% for Cr doped In2O3, which is about nine times higher than for the pure In2O3 film due to the presence of defects on the doped film surface.

Sensors and Actuators A: Physical, 2021

In this communication, we report on how the co-doping of two transition metal ions (Fe and Mn) ef... more In this communication, we report on how the co-doping of two transition metal ions (Fe and Mn) effectively improves the structural, morphological, optical, electrical and photodetection properties of CdO thin films than individual doping. For this, pure-CdO, Fe-doped, Mn-doped and (Fe-Mn) co-doped CdO thin films are deposited by spray pyrolysis technique. X-ray diffraction (XRD) patterns reveal that these films possess cubic structure and belong to the Fm-3 m space group. The Field Emission Scanning Electron micrographs hold a qualitative agreement with the crystalline sizes obtained from the XRD analysis. Energy Dispersive X-Ray Analysis approved the existence of constituent elements in the prepared films. The photoluminescence spectra identified the quality of crystal structure and the presence of defects in the prepared films. Analyzing the absorption spectra unveiled the direct bandgap values in the range 2.32 eV (for pure-CdO)-1.96 eV (for CdO:Fe(1%):Mn(1%)). The Hall Effect measurements established n-type behavior with the values of resistivity (), carrier concentration (n) and carrier mobility values in the range 5.8-7.1 m cm, 6.7−2.4 × 10 19 cm −3 and 16−37 cm 2 /Vs, respectively. Three different transport mechanisms such as ohmic, recombination-tunneling and space-charge limited current are found to play roles in the three distinct ranges of the I-V data measured for the films under study. The ideality factor values are obtained from the region where the recombination-tunneling mechanism is prevalent. The photoelectric parameters such as photo-responsivity, and external quantum efficiency are obtained. The values of these quantities pertaining to pure-CdO, CdO:Mn, CdO:Fe and CdO:Fe:Mn films vary in the range 128.4-561.3 mA/W, and 30-131.1 %, respectively. From the current study, it was found that photoresponsivity and external quantum efficiency are enhanced by a factor of four in codoped CdO films than the undoped CdO film and can find potential photodetector applications.