76 results on '"Babu, R."'
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2. Facile Homemade Spray Pyrolyzed (SnO2)1-x(CeO2)x Composite Thin Films for Visible Light Photocatalysis Application
- Author
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Arjunan, K. and Babu, R. Ramesh
- Published
- 2023
- Full Text
- View/download PDF
3. Impact of Ta doping on the optoelectronic and catalytic properties of SnO2 thin films
- Author
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Senthilkumar, P., Raja, S., Ramesh Babu, R., Kavinkumar, V., Jothivenkatachalam, K., and Vasuki, G.
- Published
- 2023
- Full Text
- View/download PDF
4. Visible light photocatalysis application of (1–x)(SnO2) − (x)(Pr2O3) composite thin films by laboratory spray pyrolysis method.
- Author
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Arjunan, K. and Babu, R. Ramesh
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THIN films , *VISIBLE spectra , *ULTRAVIOLET spectroscopy , *FIELD emission electron microscopy , *ENERGY levels (Quantum mechanics) , *X-ray photoelectron spectroscopy - Abstract
The composite metal oxide thin films, (1–x)(SnO2)-(x)(Pr2O3) (where x = 0.0, 0.25, 0.50, 0.75, 1.0 at.%), were coated using the laboratory spray pyrolysis method. Their structural, vibrational, morphological, compositional and optical properties were analyzed using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), ultraviolet–visible near-infrared spectroscopy (UV–Vis. NIR) and photoluminescence spectroscopy (PL). XRD studies confirmed that the deposited (1–x)(SnO2)-(x)(Pr2O3) composite thin film adhered to the tetragonal phase for x = 0.0, the hexagonal phase for x = 1.0, and a combined phase for x = 0.25, 0.50, and 0.75 at.%. Additionally, the crystallite size decreased with the addition of rare earth composite. FTIR spectra revealed the basic vibrational modes of Sn–O and Pr–O. XPS analysis disclosed the Sn, Pr, and O chemical valence states, as well as oxygen vacancies on the surface. FESEM analysis showed that the morphology of composite thin films was significantly altered by Pr2O3 content. EDX study revealed the presence of Sn, Pr, and O elements. Root mean square (RMS) roughness values identified through AFM analysis could contribute to enhancing photocatalytic performance. PL analysis revealed the recombination of photo-generated charge carriers, surface, and lattice oxygen defects. The calculated edge potential of the conduction and valence bands in SnO2, Pr2O3, and their composites revealed a defect energy level, which is efficient for visible photocatalytic dye degradation capabilities. A high visible light photocatalytic efficiency of 93%, against methylene blue dye, of the composite thin film (0.50SnO2 − 0.50Pr2O3) is primarily attributed to its extended light absorption capability, appropriate band edge alignment between SnO2 and Pr2O3, minimal electron–hole pair recombination, and efficient charge transfer. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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5. Investigation of nanostructured TiO2 thin film coatings for DSSCs application using natural dye extracted from jabuticaba fruit as photosensitizers
- Author
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Sampaio, D. M., Babu, R. Suresh, Costa, H. R. M., and de Barros, A. L. F.
- Published
- 2019
- Full Text
- View/download PDF
6. Fabrication of samarium doped SnO2 thin films using facile spray pyrolysis technique for photocatalysis application.
- Author
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Arjunan, K. and Ramesh Babu, R.
- Abstract
Samarium (Sm) doped SnO
2 thin films were fabricated onto micro-glass slides using a facile spray pyrolysis technique. The influence of samarium doping concentration (0.25, 0.50, and 1.00 wt%) on the photocatalytic characteristics of SnO2 thin film is investigated using various characterization studies. X-ray diffraction (XRD) studies show that the tin oxide (SnO2 ) and Sm doped SnO2 thin films possess average crystallite size of 48, 46, 45, and 44 nm corresponding to the tetragonal rutile structure. Micro-Raman spectroscopy analysis confirms the tetragonal phase of SnO2 and Sm doped SnO2 films from the fundamental peaks at 476, 637 and 777 cm−1 . X-ray photoelectron spectroscopy (XPS) studies reveal that tin and Sm ions exist in the Sm3+ and Sn4+ oxidation states, respectively. Field emission scanning electron microscopy (FESEM) studies demonstrate that various Sm concentrations effectively enhance the SnO2 film surface. The composition of SnO2 and Sm doped SnO2 films is analyzed by energy dispersive X-ray spectroscopy (EDX) analysis. The deposited films possess an average transmittance ranging from 64 to 94%. The band edge potential calculation for SnO2 and Sm doped SnO2 thin films indicates the presence of an impurity energy level, which is favourable for visible light performance. Photoluminescence (PL) analysis demonstrates that the prepared thin films have strong emissions at around 493 and 520 nm. The 0.25 wt% Sm doped SnO2 thin film possesses visible light photocatalytic degradation efficiency of 85% against the methylene blue (MB) dye. [ABSTRACT FROM AUTHOR]- Published
- 2024
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7. Facile Homemade Spray Pyrolyzed (SnO2)1-x(CeO2)x Composite Thin Films for Visible Light Photocatalysis Application.
- Author
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Arjunan, K. and Babu, R. Ramesh
- Abstract
Metal oxide composite thin films (SnO
2 )1-x (CeO2 )x (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 vol. %) were deposited by facile homemade spray pyrolysis technique. X-ray diffraction (XRD) analysis confirms that the deposited (SnO2 )1-x (CeO2 )x composite belongs to the tetragonal rutile phase for x = 0.0 (SnO2 ), cubic phase for x = 1.0 (CeO2 ) and blend phase of SnO2 and CeO2 for x = 0.2, 0.4, 0.6, 0.8 vol. %. The X-ray peak line-broadening, lattice stress, energy density, microstrain and crystallite size are determined using the Williamson-Hall (W–H) analysis and Size-Strain Plot (SSP) method. Sn–O and Ce–O vibrational modes are confirmed using the room temperature micro-Raman analysis. The chemical state of Sn, Ce and O is determined using X-ray photoelectron spectroscopy (XPS) analysis. Field emission scanning electron microscopy (FESEM) study shows that various vol. % of (x) from 0.2 to 0.8 significantly alter the composite morphology. Energy dispersive X-ray spectroscopy (EDX) analysis reveals the presence of Sn, Ce and O in (SnO2 )1-x (CeO2 )x composite thin films. The atomic force microscopy (AFM) analysis revealed that the root mean square roughness of the (SnO2 )1-x (CeO2 )x composite thin films varies from 10 to 55 nm with respect to x. The average optical transmittance in the wavelength region (400–1100 nm) varies between 56 and 74%. The band edge potential calculation for a SnO2 and (SnO2 )1-x (CeO2 )x composite indicates the presence of an impurity energy level, which is beneficial for visible light photocatalytic performance. Photoluminescence (PL) analysis exhibits blue emission enhancement at around 490 nm of the visible region. The highest photocatalytic dye degradation efficiency of 89% is obtained for (SnO2 )0.6 (CeO2 )0.4 composite thin film against Methylene Blue (MB) dye under visible light irradiation. [ABSTRACT FROM AUTHOR]- Published
- 2023
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8. Impact of Ta doping on the optoelectronic and catalytic properties of SnO2 thin films.
- Author
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Senthilkumar, P., Raja, S., Ramesh Babu, R., Kavinkumar, V., Jothivenkatachalam, K., and Vasuki, G.
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THIN films ,CATALYTIC doping ,MALACHITE green ,ELECTRICAL resistivity ,BAND gaps ,ZINC oxide films ,TANTALUM ,IRRADIATION - Abstract
Spray-deposited un-doped SnO
2 and SnO2 :Ta (Ta: 0.5, 1.0, 1.5, and 2.0 wt.%) thin films were studied through various characterization techniques. The XRD results confirmed the tetragonal phase of SnO2 , and the calculated crystallite size varied between 33 and 43 nm. The SEM micrographs showed that Ta-dopant significantly altered the morphology of SnO2 thin films. The chemical states of SnO2 :Ta were confirmed by XPS analysis. A high average transmittance (~ 80%) was obtained, and band gap values varied between 3.60 and 3.42 eV. Relatively, minimum electrical resistivity (9.7 × 10–4 Ω.cm), Hall mobility (43 cm2 /V.s), low value of sheet resistance (32 Ω/□), and high optoelectronic efficiency (ɸ = 1.29 × 10–3 Ω−1 ) were obtained for 1.0 wt.% Ta-doping. The highest photodegradation efficiency (94.38%) was achieved against malachite green aqueous dye solution for 1.5 wt.% Ta-doping. These results clearly show that 1.0 and 1.5 wt.% SnO2 :Ta films could be potential candidates for photocatalytic dye degradation and TCO applications. [ABSTRACT FROM AUTHOR]- Published
- 2023
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9. Cu-poor chalcostibite CuSbS2 thin films for inverted photovoltaic applications.
- Author
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Chinnaiyah, Sripan, Alagarasan, Devarajan, Ganesan, R., and Babu, R. Ramesh
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X-ray emission spectroscopy ,THIN films ,FIELD emission electron microscopy ,X-ray photoelectron spectroscopy ,SOLAR cells ,ULTRAVIOLET-visible spectroscopy - Abstract
In the present work, thermally evaporated Cu-poor CuSbS
2 (Copper antimony disulphide—CAS) thin films are prepared with the precursor of Cu-poor CuSbS2 alloys. X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and UV–Visible spectroscopy have been used to characterise the prepared films to determine their potentiality as absorber layer materials for photovoltaic applications. By replacing the standard window layer of i-ZnO (intrinsic-zinc oxide) with one-dimensional (1D) n-type TiO2 (titanium dioxide) and an active layer of stoichiometry-adjusted CAS, we investigated the effect of architecture on photovoltaic (PV) performance. Solar cells with Cu-poor and stoichiometric-adjusted CAS absorbers have a Voc of 189 mV and a Jsc of 0.737 mA/cm2 . The designed solar cell device with the structure FTO/TiO2 /CdS/CAS/Al has a power conversion efficiency (PCE) of > 1%. [ABSTRACT FROM AUTHOR]- Published
- 2023
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- View/download PDF
10. Incorporation of Ti3+ metal ions in chemically spray deposited CdO thin films for optoelectronic and chem-resistive based formaldehyde gas sensor applications.
- Author
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Velusamy, P., Ramesh Babu, R., Sathiya, M., Ahmad, Awais, Alothman, Asma A., Sheikh Saleh Mushab, Mohammed, Elamurugu, Elangovan, Senthil Pandian, M., and Ramasamy, P.
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THIN films , *GAS detectors , *METAL ions , *CARRIER density , *CHARGE carriers , *ELECTROSPRAY ionization mass spectrometry , *RAMAN scattering - Abstract
The surface-microstructural dependent optoelectronic and gas sensing characteristics of Ti-doped CdO thin films spray deposited on tiny glass substrates at 300 °C were examined in depth. XRD measurements revealed the polycrystalline nature of CdO films. It also revealed that the typical crystallite size of CdO films varies between 28 and 41 nm. XPS analysis validated the oxidation status of the Cd, O, and Ti components. The Cd–O metal oxide modes of vibration are confirmed by Raman analysis at ambient temperature. Ti-dopant significantly modifies the surface microstructure of CdO thin films. The predicted optical bandgap of the Ti-doped CdO thin film varies between 2.38 and 2.47 eV. The Ti-doping of 0.75 wt% results in a high typical transparency value of 91%. With a rise in Ti-doping concentration, the charge carrier concentration and resistivity are arbitrarily altered. CdO films with 0.75 wt% Ti had a mobility of 94 cm2 V−1 s−1. For the 0.75 wt% Ti doping, a high figure of merit (152.5 × 10−4 Ω−1) is produced. The formaldehyde gas response of the 0.75 wt% Ti-doped CdO thin film is high (81%). The optical band-gap and degree of crystallinity of CdO thin films are thought to be controlled by Ti dopant. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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11. Spray-Deposited Rare Earth Metal Ions (La3+ and Sm3+) Substituted CoFe2O4 Thin Films for NH3 Gas-Sensing Applications.
- Author
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Vadivel, M., Ramesh Babu, R., and Sridharan, M.
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SAMARIUM , *RARE earth metals , *RARE earth ions , *THIN films , *GAS detectors , *SURFACE roughness - Abstract
We report here the NH3 gas-sensing properties of homemade spray deposited pristine and different concentrations of La3+ and Sm3+ ions substituted CoFe2O4 thin films. XRD findings reveal that the deposited pristine and metal ions substituted CoFe2O4 thin films exhibit the single-phase cubic spinel structure. Also, the calculated average crystallite size was found to decrease from 21 to 17 nm and 21 to 14 nm for La3+ and Sm3+-substituted CoFe2O4 thin films, respectively. AFM topography images show a variation in surface morphology and roughness of CoFe2O4 thin films by the substitution of La3+ and Sm3+ ions in the Fe3+ site, thereby affecting the gas-sensing behavior of CoFe2O4 thin films. Gas-sensing measurement demonstrates that the substitution of La3+ and Sm3+ ions in the CoFe2O4 matrix significantly enhances the gas-sensing characteristics such as sensitivity, gas response, and recovery time of pristine CoFe2O4 thin films. Hence, the experimental results obtained from the present study show that La3+ and Sm3+-ion-substituted CoFe2O4 thin films offer greater potential for the fabrication of room temperature NH3 gas sensors even for low ppm concentrations. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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12. Room-temperature NH3 gas-sensing characteristics of spray-deposited transition metal ions substituted CoFe2O4 thin films.
- Author
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Vadivel, M., Ramesh Babu, R., and Sridharan, M.
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TRANSITION metal ions , *ATOMIC force microscopy , *GAS detectors , *SURFACE topography , *THIN films , *POISONS - Abstract
We report here the structural, morphological and gas-sensing characteristics of 1, 3 and 5 wt. % Cr3+- and Zn2+-substituted CoFe2O4 thin films prepared using the facile solution-based spray pyrolysis experimental method. Structural study confirms the polycrystalline nature and single-phase cubic spinel structure of the deposited films. Atomic force microscopy (AFM) study demonstrates that the substitution of transition metal ions significantly influences the surface topography of pristine CoFe2O4 thin films. Results from the gas sensor analysis reveal an excellent sensing behavior of Cr3+-substituted CoFe2O4 at room temperature, in particular, the maximum gas response is observed for 1 wt. % Cr3+-substituted CoFe2O4 thin films than that of pristine and other substituted CoFe2O4 thin films, which is due to the substitution of Fe3+ by Cr3+ provides more reactive sites, at this particular concentration, and thus relatively higher response. In addition, the selectivity, gas response, response time and recovery time of CoFe2O4 thin films have been explored in the present study, and the deposited thin films show high selectivity for NH3 gas than that of other tested toxic gases. Hence, based on the results obtained, spray-deposited Cr3+-substituted CoFe2O4 thin films would act as potential candidates for the fabrication of NH3 sensor devices even for detecting low ppm gas concentrations at room temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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- View/download PDF
13. Investigation of substrate temperature effect on the properties of spray deposited Ta-doped SnO2 thin films.
- Author
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Ramarajan, R., Thangaraju, K., Joseph, D. Paul, Babu, R. Ramesh, Sharma, Veerendra K., Prajapat, C. L., and Yusuf, S. M.
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TEMPERATURE effect ,THIN films ,BAND gaps ,TIN oxides ,ACTIVATION energy ,SURFACE morphology - Abstract
In this work, we present the results of deposition of Ta-doped SnO
2 (TTO) thin films by cost effective spray pyrolysis method as a function of substrate temperature. The XRD spectra of TTO films show polycrystalline nature with tetragonal structure. The average crystallite size and textured coefficient values were changing as a function of substrate temperature. The surface morphology of the TTO films was also influenced by the substrate temperature. The film deposited at 400 °C shows a maximum transmittance of 86 % in the visible region (550 nm). The band gap value decreased marginally for increasing substrate temperature. The lowest resistivity (6.06×10−4 Ω cm) and sheet resistance (23.1 Ω/□) were achieved for film deposited at 400 °C. The temperature dependent electrical study carried out in the temperature range 30 °C to 350 °C indicated the presence of two different conduction mechanisms with different activation energies. The film deposited at 400 °C showed the higher figure of merit value (1.07×10-2 Ω−1 ). [ABSTRACT FROM AUTHOR]- Published
- 2020
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14. Influence of Cd doping on the Structural, Optical and Morphological Properties of SnO2 Thin Films.
- Author
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Senthilkumar, P., Vasuki, G., Ramesh Babu, R., and Raja, S.
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THIN films ,OPTICAL properties ,BAND gaps ,TIN oxides ,SURFACE properties ,HEAVY metals ,METALLIC thin films - Abstract
In the present work, Cadmium doped tin oxide (Cd:SnO
2 ) thin films were deposited on glass substrates at 400ºC using a simple homemade spray pyrolysis technique. The effect of Cd doping concentration (2, 4, 6 and 8 at.%) on the structural, optical and surface morphological properties was investigated. The XRD results revealed that all the prepared sample are polycrystalline in nature. The optical studies showed that the average transmittance of all the prepared thin films is about 90 % in the visible region. The band gap energy increases from 3.44 eV to 3.72 eV with increasing Cd concentration. The SEM micrographs showed the rectangular shape morphology for undoped samples, further it slightly varied with increasing the doping content of Cd. AFM results reveal that SnO2 film shows minimum roughness for 4 at.% of Cd doping. Energy dispersive X- ray studies confirmed the presence of Sn and O elements for undoped samples Sn, O and Cd elements for doped samples. [ABSTRACT FROM AUTHOR]- Published
- 2020
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15. Optimization and Transport Properties of ‘Nb’ Doped SnO2 Thin Film as an Alternate TCO Application.
- Author
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Ramarajan, R., Kovendhan, M., Babu, R. Ramesh, Thangaraju, K., and Joseph, D. Paul
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THIN films ,METALLIC thin films ,SURFACE morphology ,SHEET metal ,TIN oxides - Abstract
In this work, we present the results of optimization of ‘Nb’ doped tin oxide (Sn
1-x Nbx O2 , NTO) thin films deposited by cost effective spray pyrolysis method onto glass substrates using 0.3 M and 0.5 M precursor solutions. The XRD spectrum of thin films clearly indicate polycrystalline nature with tetragonal structure. The 0.5 M concentration thin film was more textured than the 0.3 M concentration thin film indicating the influence of precursor concentration in textured growth. The surface morphology of the films showed twisted metal sheet like structure and the composition was confirmed by elemental analysis. The 0.5 M NTO thin film had a maximum average transmittance of 72% at 550 nm. The band gap values estimated from the tauc plot around 3.4 eV well matched with previous reports. The lowest sheet resistance of 30 Ω/□ and resistivity value of 9.05×10-4 Ω cm were achieved for the films prepared using 0.5 M precursor solution. The NTO thin film was found to possess two different conduction mechanism at two different temperature range from the Arrhenius plot (300 K to 572 K). The film deposited using 0.5 M solution has higher figure of merit value of 2.48×10-2 Ω-1 and is better than the film deposited using 0.3 M precursor solution. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
16. Investigation of nanostructured TiO2 thin film coatings for DSSCs application using natural dye extracted from jabuticaba fruit as photosensitizers.
- Author
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Sampaio, D. M., Babu, R. Suresh, Costa, H. R. M., and de Barros, A. L. F.
- Abstract
Solar power is a renewable and promising solution to the today's world energy needs. Recently, researchers in finding an alternative energy resource for the next generation lead to the production of efficient photovoltaic cells. Herein, dye-sensitized solar cells (DSSCs) containing semiconducting nanostructured TiO
2 thin film photoanodes were fabricated by spin-coating technique, using a self-constructed spin coater, which is a simple and cost-effective method. The composition and superficial characteristics of the films were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Microscopic analysis revealed the electrode surface morphology, and microstructure were influenced by spin-coating technique compared to doctor blade method. The natural dyes of anthocyanin were extracted from jabuticaba (Plinia cauliflora) fruit using a simple extraction technique, used as photosensitizers in DSSCs and their characteristics were studied. The extracts showed the UV–Vis absorptions in the 450–600 nm range with broad maxima at ~ 545 nm. FTIR showed the presence of anthocyanin in the dye molecules of jabuticaba fruit, which can be related to a better photon to electron conversion. The photoelectrochemical performance and the efficiency of assembled DSSCs using jabuticaba fruit dye extract were evaluated, and efficiency enhancement was obtained by spin-coated TiO2 electrodes. The efficiency and fill factor of the DSSC using jabuticaba fruit dye were 0.13% and 0.29%, respectively. The results successfully showed that the DSSC, using jabuticaba fruit extract as a dye photosensitizer, is valuable for the preparation of eco-friendly, less-expensive, renewable, and clean sources of energy. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
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17. Effect of substrate temperature on the structural, morphological and optical properties of copper bismuth sulfide thin films deposited by electron beam evaporation method.
- Author
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Bhuvaneswari, P. V., Ramamurthi, K., and Babu, R. Ramesh
- Subjects
THIN films ,ELECTRON beam curing ,BISMUTH ,MAGNETRON sputtering ,SPUTTERING (Physics) ,SULFIDES ,SUBSTRATE integrated waveguides - Abstract
Copper bismuth sulfide thin films were deposited at 200 °C, 300 °C, 400 °C and 500 °C on the glass substrates by electron beam evaporation method. X-ray diffraction study revealed that the copper bismuth sulfide films of single and mixed phases were formed as a function of substrate temperatures. Substrate temperature of 300 °C and 400 °C formed single phase Cu
4 Bi4 S9 and Cu4 Bi5 S10 films respectively whereas substrate temperature of 500 °C formed mixed phases of Cu4 Bi4 S9 and Cu4 Bi5 S10 film. Crystallite size, dislocation density and microstrain of the films were modified by the various substrate temperatures. Surface morphology of the film Cu4 Bi5 S10 deposited at 400 °C examined by scanning electron microscopy showed the distribution of spherical shaped particles on the film surface. The presence of copper, bismuth and sulfur elements in the deposited films was confirmed using energy dispersive spectral studies. The calculated direct optical band gap energy of the films deposited at different substrate temperature varied from 1.47 to 1.64 eV and the absorption coefficient is in the order of 106 cm−1 . [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
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18. Influence of Cr-doping on structural, morphological, optical, dielectric and magnetic properties of KNbO3 ceramics.
- Author
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Raja, S., Ramesh Babu, R., Ramamurthi, K., and Sethuraman, K.
- Subjects
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DIELECTRIC properties , *CERAMICS , *THIN films , *X-ray photoelectron spectroscopy , *MAGNETIZATION - Abstract
In this work, we report on the structural, morphological, optical, dielectric and magnetic properties of undoped and Cr doped KNbO 3 (KNb 1- x Cr x O 3 ; x = 0.0, 0.01, 0.03 and 0.05 mol.%) synthesized at 900 °C by solid state reaction method. X-ray diffraction analysis showed the formation of single phase KNbO 3 with the orthorhombic structure. Further, the Rietveld refinement analysis revealed that no impurity or secondary phase formation related to the Cr doping. The crystallite size of KNb 1- x Cr x O 3 varies between 553 nm and 948 nm. All the characteristic Raman phonon modes of KNb 1- x Cr x O 3 confirmed the formation of compound with the orthorhombic structure. The presence of K, Nb, O and Cr elements and a shift in binding energy of Nb and O was observed by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy analyses, respectively. Surface morphology of KNb 1- x Cr x O 3 samples exhibit different morphologies, namely rods, cubes and micro edges. Diffuse reflectance spectra revealed that band gap of KNb 1- x Cr x O 3 ceramics decreases with increasing Cr doping level. The photoluminescence emission peaks at ∼410–492 nm (blue) and 520 nm (green) indicate the oxygen vacancies present in the sample. A high coercivity (593 Oe) and saturation magnetization (0.021 emu g −1 ) is obtained for 0.03 mol.% of Cr doping. The dielectric permittivity was enhanced with the increase of Cr doping concentration in KNbO 3 matrix. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
19. Spray deposited ruthenium incorporated CdO thin films for opto-electronic and gas sensing applications.
- Author
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Velusamy, P., Ramesh Babu, R., Ramamurthi, K., Elangovan, E., Viegas, J., and Sridharan, M.
- Subjects
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CADMIUM oxide , *RUTHENIUM , *THIN films , *OPTOELECTRONICS , *PYROLYSIS - Abstract
The ruthenium (Ru) doped CdO thin films were deposited by spray pyrolysis method on glass substrate, with various Ru concentrations (0.1, 0.125, 0.150, 0.175 and 0.2 wt%). The effect of Ru doping concentration on the electrical, optical, structural, microstructural and gas sensing properties was studied by Hall measurement, UV–vis–NIR spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, micro-Raman and chemi-resistivity method. The results obtained show that the carrier mobility, visible-NIR transparency, surface morphology and gas response are effectively tuned by varying Ru doping concentration. The 0.1 wt% Ru doped CdO thin film shows relatively high optical band gap (2.32 eV) and maximum transmittance (70%) in the range between 600 and 900 nm. The high electrical properties (mobility 110 cm 2 /V⋅s and carrier concentration 1.77 × 10 20 cm −3 ) are obtained for 0.150 wt% Ru doped CdO thin film. The high formaldehyde gas sensitivity (35%), fast response and recovery time are observed for 0.150 wt% Ru doped CdO thin film. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
20. Investigation on vanadium oxide thin films deposited by spray pyrolysis technique.
- Author
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Margoni, Mudaliar Mahesh, Mathuri, S., Ramamurthi, K., Babu, R. Ramesh, and Sethuraman, K.
- Subjects
VANADIUM oxide ,THIN films ,PYROLYSIS ,CRYSTALLINITY ,CHEMICAL precursors - Abstract
Vanadium oxide thin films were deposited at 400 °C by spray pyrolysis technique using 0.1 M aqueous precursor solution of ammonium meta vanadate (AMV) with two different pH values. X-ray diffraction results showed that the film prepared using aqueous precursor AMV solution (solution A; pH 7) is amorphous in nature and the film prepared by adding HNO3 in the AMV aqua solution A (solution B; pH 3) is polycrystalline in nature. Vanadium oxide film prepared from the precursor solution B is in the mixed phases of V
2 O5 and V4 O7 .Crystallinity is improved for the film prepared using solution B when compared to film prepared from solution A. Crystallite size, strain and dislocation density calculated for the film prepared from solution B is respectively 72.1 nm, 0.4554 × 10-3 lin.-2 m-4 and 1.7263 × 1014 lin.m-2 . Morphology study revealed that the size of the flakes formed on the surface of the films is influenced by the pH of the precursor solution. Average Visible Transmittance and maximum transmittance of the deposited films exceed 70% and the direct optical band gap value calculated for the films deposited from A and B solution is 1.91 eV and 2.08 eV respectively. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
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21. Effect of La doping on the structural, optical and electrical properties of spray pyrolytically deposited CdO thin films.
- Author
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Velusamy, P., Ramesh Babu, R., Ramamurthi, K., Elangovan, E., and Viegas, J.
- Subjects
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LANTHANUM , *DOPING agents (Chemistry) , *CADMIUM oxide , *PYROLYSIS , *SOLUTION (Chemistry) , *METALLIC thin films , *ELECTRIC properties of metals - Abstract
Solution based chemical spray pyrolysis technique was employed to deposit lanthanum (La) doped cadmium oxide (CdO) thin films on soda-lime microscope glass slides. X-ray diffraction (XRD) analysis revealed that deposited films are polycrystalline having cubic crystal system. The undoped and 0.25 wt % La doped CdO films show relatively intense (111) plane, which is shifted to (200) plane for doping concentrations greater than 0.50 wt %. The parameters such as lattice constants, crystallite size, micro-strain, dislocation density and texture coefficient are extracted from XRD data. Field emission scanning electron microscopy analysis confirmed the smooth and uniform surface. Energy dispersive spectroscopy analysis was used to estimate the preliminary information on elemental composition. The deposited undoped and La doped films possess optical transmittance ranging 78–82% in the visible and near infrared (NIR) region. The estimated direct optical band gap of undoped and La doped CdO thin films is varied between 2.38 eV and 2.46 eV. Hall measurements confirmed the n-type conductivity in the films. The doping-modulated mobility and carrier concentration are ranging 68 cm 2 /V s–78 cm 2 /V s, and 1.0 × 10 20 cm −3 –4.06 × 10 20 cm −3 , respectively. Room temperature micro-Raman studies confirmed the metal oxide (Cd O) bond vibrations in deposited films. A high figure of merit (11.45 × 10 −3 Ω −1 ) is obtained from 1.0 wt % La doped CdO film. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
22. Electrical and optical properties of Co:SnO thin films deposited by spray pyrolysis technique.
- Author
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Indira Gandhi, T., Ramesh Babu, R., Ramamurthi, K., and Arivanandhan, M.
- Subjects
TIN oxides ,THIN films ,PYROLYSIS ,X-ray diffraction ,SCANNING electron microscopy - Abstract
In this work, tin oxide (SnO) and cobalt doped tin oxide (Co:SnO) thin films are deposited by spray pyrolysis technique and the influence of doping concentration on the structural, morphological, electrical and optical properties of tin oxide films is analyzed and reported. X-ray diffraction pattern shows that the SnO and Co:SnO films are polycrystalline in nature and exhibit tetragonal crystal system. Co doping shifts the preferential growth orientation of SnO to (200) direction. Scanning electron microscopic studies show that the surface morphology of tin oxide films was effectively modified by various Co concentrations. X-ray photoelectron spectra of 5 at.% Co:SnO thin film reveal the presence of tin, oxygen, and cobalt. Carrier concentration and mobility of the SnO film decreases with increasing Co concentration and 0.5 at.% Co:SnO film acquires a mobility of 74 cm/V s. The average optical transmittance of SnO thin film in the range of 500-800 nm increases due to Co doping. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
23. Effect of Mn doping on the electrical and optical properties of SnO2 thin films deposited by chemical spray pyrolysis technique.
- Author
-
Indira Gandhi, T., Ramesh Babu, R., Ramamurthi, K., and Arivanandhan, M.
- Subjects
- *
TIN oxides , *MANGANESE compounds , *DOPING agents (Chemistry) , *THIN films , *OPTICAL properties , *PYROLYSIS , *THIN film deposition - Abstract
Manganese doped tin oxide (Mn:SnO 2 ) thin films were deposited by spray pyrolysis technique adding various concentrations of manganese acetate (0–8 at.%) in the spray solution of tin chloride. X-ray diffraction studies show the preferred growth along (301) direction for 0.0–2.0 at.% concentration of manganese acetate in the spray solution. Higher doping concentration of manganese acetate (4 and 8 at.%) in the solution shifts the preferred growth direction along (200) plane. Scanning electron microscopic studies reveal the change in the surface morphology of the films due to various levels of Mn doping. X-ray photoelectron spectroscopic analysis shows that in the prepared thin film manganese atoms exist in Mn 3 + state. The sheet resistance of SnO 2 film decreases from ~ 23.5 Ω/□ to 22.8 Ω/□ for 0.4 at.% doping concentration and increases with increasing Mn concentration in the solution. The average optical transmittance of SnO 2 thin film increases from 34% to 55% in the wavelength region of 550–850 nm with increase in Mn concentration. Mn concentration in the films influences the intensity of the photoluminescence emission peak observed for SnO 2 film at 398 nm. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
24. Theoretical and Experimental Evaluation of Structural and Optical Properties of Novel Zinc-Benzimidazole Metal Complex Doped in Polystyrene Matrices.
- Author
-
Praveen, P. A. and Babu, R. Ramesh
- Subjects
- *
ZINC compounds , *POLYSTYRENE , *BENZIMIDAZOLES , *METAL complexes , *METAL microstructure , *OPTICAL properties of metals , *PHYSICS experiments - Abstract
A novel zinc incorporated benzimidazole metal complex (diacetobis (lH-benzimidazole) Zn(II)) is synthesized by a simple chemical route. The structure of the obtained complex is predicted using FTIR and EPR spectroscopy and further confirmed using semiempirical simulation of vibrational frequencies. Theoretical energy gap of the complex is about 3.2 eV and the hyperpolarizability calculations show that the third harmonic generation dominates over other mechanisms in the complex. Recorded absorption spectrum of the complex shows a broad absorption band between 200 and 300 nm corresponding to λ-λ transitions. To evaluate the third order nonlinear optical properties experimentally, the complex is doped into a polystyrene matrix with different weight percentages and fabricated as freestanding films. The films are subjected to Z-scan analysis and from the open and closed aperture scans the samples are found to have a reverse saturable absorption and self focusing effect. The calculated third order susceptibilities are of the order of 10-4 esu, which is one of the largest values reported in literature. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
25. Structural, microstructural, optical and electrical properties of spray deposited rare-earth metal (Sm) ions doped CdO thin films.
- Author
-
Velusamy, P., Babu, R., Ramamurthi, K., Viegas, J., and Elangovan, E.
- Subjects
ELECTRIC properties of thin films ,CADMIUM oxide ,THIN films ,OPTICAL properties ,MICROSTRUCTURE ,THIN film deposition ,RARE earth metals ,DOPED semiconductors ,X-ray diffraction - Abstract
Rare-earth metal, samarium (Sm) ions, doped cadmium oxide (CdO) thin films were deposited on microscopic glass substrates at 300 °C by a homemade spray pyrolysis experimental setup. The deposited films were characterized for their structural, microstructural, optical and electrical properties. X-ray diffraction analysis confirmed that the deposited films belong to the cubic crystal system. The undoped films show a slight preferential growth along (111) diffraction plane, and the (200) plane emerged as the preferential growth direction when the Sm-doping is higher than 0.75 wt%. Field emission scanning electron microscopy analysis reveals that the average grain size and surface morphology of CdO films are effectively modified by various Sm-doping concentration. The elemental composition of the deposited films was analyzed using energy dispersive spectroscopy. The metal oxide (Cd-O) bond vibrations were observed at 319, 389, 551,779 and 941 cm by micro-Raman studies at room temperature. Oxidation state of Sm was confirmed by X-ray photoelectron spectroscopy analysis. A transmittance (ranging 83-86 %) in the visible and NIR region was observed for the various Sm concentrations. The optical band gap estimated varies between 2.39 and 2.67 eV, depending on the Sm-doping concentration. The negative sign of Hall coefficient confirmed the n-type conductivity and the mobility and carrier concentration are in the 45-78 cm/V s, and 1.0 × 10-3.36 × 10 cm range respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
26. Effect of Transition Metal Ion (Ni) Doping on the Structural, Optical and Electrical Properties of CdO Thin Films by Spray Pyrolytic Technique.
- Author
-
Velusamy, P., Babu, R. Ramesh, and Ramamurthi, K.
- Subjects
- *
TRANSITION metal ions , *DOPING agents (Chemistry) , *CRYSTAL structure , *OPTICAL properties of metals , *CADMIUM oxide , *ELECTRIC properties of metals , *THIN films , *PYROLYSIS - Abstract
Preparation of undoped and Ni doped CdO thin films were carried out by spray pyrolysis technique on glass substrate at 300°C. The structural, morphological, electrical and optical properties of Ni doped CdO films are analyzed by different analytical tools. XRD pattern reveals that all the films are polycrystalline nature with cubic structure. Morphological study reveals the spherical like morphology and smooth surface. Electrical study reveals the n-type semiconducting nature of CdO and optical study shows that the optical band gap varies between 2.35 and 2.52 eV. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
27. Structural, morphological, electrical and optical studies of Cr doped SnO2 thin films deposited by the spray pyrolysis technique
- Author
-
Gandhi, T. Indira, Ramesh Babu, R., and Ramamurthi, K.
- Subjects
- *
CRYSTAL structure , *ELECTRIC properties of metals , *OPTICAL properties of metals , *DOPED semiconductors , *CHROMIUM , *TIN oxides , *THIN films , *PYROLYSIS - Abstract
Abstract: Tin oxide (SnO2) and chromium (Cr) doped tin oxide (Cr:SnO2) thin films were deposited on the preheated glass substrates at 673K by spray pyrolysis. Concentration of Cr was varied in the solution by adding chromium (III) chloride hexahydrate from 0 to 3at%. The effect of Cr doping on the structural, electrical and optical properties of tin oxide films is reported. X-ray diffraction pattern confirms the tetragonal crystal structure for undoped and Cr doped tin oxide films. Scanning electron microscopic photographs show the modification of surface morphology of tin oxide film due to varying concentration of Cr. X-ray photoelectron spectra of Cr:SnO2 (3at%) thin film revealed the presence of carbon, tin, oxygen, and chromium. Carrier concentration and mobility of the SnO2 films decrease with increasing concentration of Cr and 0.5at% Cr doped tin oxide film acquires a mobility of 70cm2/Vs. Average optical transmittance in the 550–850nm range varies from 38% to 47% with varying Cr concentration in the solution. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
28. Amperometric determination of l-dopa by nickel hexacyanoferrate film modified gold nanoparticle graphite composite electrode
- Author
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Prabhu, P., Suresh Babu, R., and Sriman Narayanan, S.
- Subjects
- *
NICKEL compounds , *CONDUCTOMETRIC analysis , *THIN films , *COLLOIDAL gold , *NANOPARTICLES , *GRAPHITE , *COMPOSITE materials , *ELECTRODES - Abstract
Abstract: Surface modification of graphite electrode with nickel hexacyanoferrate (NiHCF) film through 2-mercaptoethylamine (MEA) capped gold nanoparticle (GNP) was achieved by a novel fabrication approach. The NiHCF modified electrode exhibits a distinct pair of redox peaks corresponding to anodic and cathodic reactions of hexacyanoferrate (II/III) of NiHCF with a formal potential of 0.33V versus SCE. l-Dopa, is a potential chemotherapeutic drug used for the treatment of a neurodegenerative disease like Parkinson''s disease (PD). l-Dopa was successfully determined by NiHCF modified electrode in the concentration range of 0.82μM to 2.5mM with a good sensitivity of 0.363μA/μM. A reduction in overpotential of 200mV with a detection limit of 0.53μM was obtained. Determination of l-dopa in commercial tablets was also investigated by the proposed sensor. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
29. Enhancement in optoelectronic properties of lanthanum co-doped CdO: Zn thin films for TCO applications.
- Author
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Sarath babu, R., Narasimha murthy, Y., Vinoth, S., Isaac, R.S. Rimal, Mohanraj, P., Ganesh, V., Algarni, H., and AlFaify, S.
- Subjects
- *
THIN films , *LANTHANUM , *QUANTUM efficiency , *SURFACE morphology , *LIGHT intensity , *ZINC oxide films - Abstract
This work reports on structural, electrical, optical, and photosensing properties of La and Zn co-doped CdO thin films. The co-doped CdO thin films were prepared on glass substrates using the nebulizer spray method at 350 °C. From the structural analysis, a decrease in the crystallite size from 20 to 16 nm is observed against the incorporation of La in CdO:Zn. Inclusion of La in CdO:Zn has also changed the surface morphology with a reduction in the roughness of the thin film samples. EDX analysis confirmed the incorporation of La with CdO: Zn in the prepared films. The bandgap value of the prepared samples increased with the increase in La concentration. A 1.5 wt% of La co-doped with CdO:Zn thin film sample produces low resistivity of 6.81 × 10-4 Ω cm and a better figure of merit of 8.4 × 10 −4 Ω-1. Finally, the fabricated photodetector with 1.5 wt% of La co-doped with CdO:Zn thin film shows a higher photocurrent and an ideality factor value of 3.4. The photosensing properties of the fabricated (p-Si/CdO–Zn–La (1.5%)) photodetector shows a higher responsivity (R) value of 1.18 AW-1, specific detectivity (D*) value of 4.90 × 109 Jones, and external quantum efficiency (EQE) value of 274% with 3.0 mW/cm2 light intensity. The switching characteristics of the photodetector show a faster rise time (2.9s) and fall time (3.6s) suggesting the fabricated device suitable for photosensing applications. • Doping of La in CdO:Zn has changed the surface morphology with a reduction in the roughness of the samples. • A 1.5 wt% of La co-doped CdO:Zn sample produces low resistivity of 0.68 Ωcm and a better figure of merit of 8.4 × 10 −4 Ω-1. • Fabricated p-Si/CdO–Zn–La (1.5%)) photodetector shows a higher responsivity (R) value of 1.18 AW-1, specific detectivity (D*) value of 4.90 × 109 Jones, and external quantum efficiency (EQE) value of 274%. • The switching characteristics of the photodetector show a faster rise time (2.9s) and fall time (3.6s). [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
30. Influence of Boron Doping on the Structural, Optical and Electrical Properties of CdO thin films by Spray Pyrolysis Technique.
- Author
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Velusamy, P., Babu, R. Ramesh, and Ramamurthi, K.
- Subjects
- *
CADMIUM oxide , *BORON , *DOPING agents (Chemistry) , *THIN films , *OPTICAL properties , *ELECTRIC properties of thin films , *PYROLYSIS , *THIN film deposition - Abstract
Cadmium oxide and Boron (B) doped Cadmium oxide thin films were deposited using spray pyrolysis technique. The structural, morphological, electrical and optical properties of undoped and B doped CdO films are analyzed by varying the dopant concentration in the solution. The structural study shows the polycrystalline nature and cubic structure of undoped and B doped CdO thin films. Surface morphological study reveals that the grains are spherical in shape. Optical and electrical studies showed n-type semiconducting nature and optical band gap of 2.44 eV of deposited thin films. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
31. Linear and Nonlinear Optical Properties of Mn doped Benzimidazole Thin Films.
- Author
-
Praveen, P. A., Babu, R. Ramesh, Prabhakaran, S. P., and Ramamurthi, K.
- Subjects
- *
NONLINEAR optics , *MANGANESE , *DOPING agents (Chemistry) , *BENZIMIDAZOLES , *THIN films , *OPTICAL properties , *CHEMICAL solution deposition , *TEMPERATURE effect - Abstract
In the present work, the Mn doped benzimidazole (BMZ) thin films were prepared by simple chemical bath deposition technique. The material was directly deposited as thin film on glass substrates and the metal concentration in the solution was varied in weight percentage in order to investigate the dopant effect on the properties of thin films. Similarly, the Mn doped BMZ films were deposited in different solution temperature to study the effect of deposition temperature on the properties of thin films. The PXRD and FT-IR spectroscopy are used to study the structural and the presence of functional groups in the BMZ medium. Depending upon the solution temperature, thickness of the films varying from 0.6 to 1.2 µm and the optical transparency of the samples increases with the increasing temperature up to 50 °C. Second Harmonic Generation (SHG) efficiency of the films is measured for all the films. Third order nonlinear optical properties of the films were analyzed using Zscan technique. The experimental results show that Mn doped BMZ films exhibits saturation absorption and negative nonlinearity. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
32. Enhanced optoelectronic and catalytic properties of Sm doped SnO2 thin films.
- Author
-
Senthilkumar, P., Raja, S., Ramesh Babu, R., Sriramkumar, M., Jothivenkatachalam, K., and Vasuki, G.
- Subjects
- *
THIN films , *PHOTOCATHODES , *ENERGY dispersive X-ray spectroscopy , *STANNIC oxide , *MALACHITE green , *X-ray photoelectron spectroscopy - Abstract
Herein, we report the optoelectronic and malachite green (MG) aqueous dye model pollutant degradation characteristics of samarium (Sm) doped tin oxide (SnO 2 :Sm) thin films deposited on glass substrate by chemical spray pyrolysis technique. The tetragonal crystal structure and polycrystalline nature were elucidated from X-ray diffraction (XRD) analysis, and the calculated crystallite size using Scherrer's relation was found to vary between 36 and 45 nm. A high optical transparency of 92 % was achieved for SnO 2 :Sm (3 wt%). The extrapolation of linear fit indicates a slight decrement in the band gap. Energy dispersive X-ray analysis (EDAX) confirmed the presence of Sn, O and Sm elements and their composition. The quantitative compositional percentage of Sn, O and Sm was determined by X-ray photoelectron spectroscopy (XPS) analysis. The scanning electron micrographs (SEM) showed polyhedron-like shaped grains with cracks and void-free film surface. The 3 wt% Sm:SnO 2 thin film exhibited a higher average surface roughness (19.63 nm) than other films. Strong ultraviolet (365 nm), blue (493 nm), and green (520 nm) emissions were observed for all the films, as recorded by photoluminescence (PL) studies. High electron concentration (7.9 × 1020/cm3), low resistivity (0.356 × 10−3 Ω cm), and a high figure of merit (FOM, 5.11 × 10−2 Ω−1) were obtained for 3 wt % of SnO 2 :Sm thin films. Furthermore, a relatively high photocurrent (8.22 mA) was attained for the 3 wt% Sm:SnO 2 thin film. Enhanced photocatalytic efficiency (95 %) was achieved for the 4 wt% Sm:SnO 2 film against MG dye aqueous solution. The results obtained in the present study demonstrate high optical transparency, electrical conductivity, enhanced FOM, and photocatalytic degradation efficiency for 3 and 4 wt% Sm-doping, respectively. Therefore, Sm-doped SnO 2 could be useful for developing and designing novel devices for optoelectronic and photocatalytic applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Investigation of structural, optical, electrical and mechanical properties of transparent conducting 'Ag' electrodes.
- Author
-
Babu, R. Veera, Fernandes, Jean Maria, Kovendhan, M., Purushothamreddy, Nandarapu, Muniramaiah, Reddivari, Arockiakumar, R., Karthiselva, N.S., and Joseph, D. Paul
- Subjects
- *
OPTOELECTRONIC devices , *SCANNING probe microscopy , *HALL effect , *THIN films , *YIELD surfaces , *METALLIC films - Abstract
The high flexibility and excellent optoelectrical properties of thin metal films hold great potential for their use as transparent conducting electrodes in large-area flexible optoelectronic devices. Thermally evaporated transparent conducting silver (Ag) thin films (48–75 nm) are characterized using X-ray diffraction, scanning electron microscopy, scanning probe microscopy, UV–Vis–NIR spectroscopy, Hall effect, Nanoindentation and Kelvin probe techniques. Significant textured growth along (111) crystal plane direction is observed. The film with least thickness exhibits interesting wrinkled surface morphology. Surface roughness is observed to increase with film thickness. High transmittance and considerable transparency are observed in UV and NIR regions, respectively. Surface work function (4.7–4.9 eV) is determined from Kelvin probe measurements. Nanoindentation studies indicate reduced hardness with increasing film thickness. These experiments suggest that Ag film of thickness 63 nm shows better optical and electrical properties and may be a potential transparent conducting supplement for specific applications like transparent electrodes and interconnects. • Thin Ag thin films 60 nm act as potential transparent conducting electrodes. • Interesting wrinkled surface morphology is observed for film with least thickness. • High optical transmittance is observed in the UV and IR region. • Kelvin probe measurements on Ag films yield surface work function 4.7 eV - 4.9 eV. • Electrical and nanoindentation measurements show superior properties of Ag films. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
34. Improved optoelectronic properties of Terbium co-doped CdO:Zn thin films coated by nebulizer spray pyrolysis method.
- Author
-
Sarath babu, R., Narasimha murthy, Y., Hari Prasad, K., Ganesh, V., and AlFaify, S.
- Subjects
- *
TERBIUM , *THIN films , *NEBULIZERS & vaporizers , *ATOMIC force microscopes , *TUBERCULOSIS , *DOPING agents (Chemistry) - Abstract
Terbium co-doped CdO:Zn thin films have been coated by the facile and an efficient spray pyrolysis technique on the substrate of glass to tune its optical and electrical properties. From XRD analysis, all the diffraction peaks strongly exhibit polycrystalline nature with perfect cubic structure followed by preferential orientation was changed from (111) plane to (200) plane. The nature of the crystal structure and crystallite size is reduced from 20.4 to 16.5 nm by increasing Tb doping concentration due to defects in the lattice. The atomic force microscope AFM mages clearly show that the film's grain size decreases with the Tb dopant. The elements such as Cd, Zn, O, and Tb exists in the elemental mapping and EDS spectra. The transmittance is varied from 70, to 82% at 800 nm, and the maximum bandgap of 3.06 eV is observed for 1.5 wt.% degenerate doping concentration. PL emission at 435 nm shows a high intense peak attribute to the crystalline quality of the film. The electrical property of the film has been greatly improved with doping concentration, which is useful for optoelectronic devices. The TCO based on the 1.5 wt.% Tb co-doped CdO:Zn film shows an improved performance (higher transmission of 82%, lowest resistivity of 7.48 × 10−4 Ω cm, the highest carrier concentration of 11.3×1020 cm−3). These results propose a much simpler route to achieve high-quality Terbium co-doped CdO:Zn thin films for TCO applications. •.Performance of CdO thin films was maximised by Zn and rare earth Tb codoping. •.Optimisations of optoelectronic properties are done through doping. •.Detailed optical and electrical properties of Tb Co-doped CdO:Zn TCO material was reported. •.An overall optical and electrical properties enhanced by 1.5% Tb co-doping. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
35. In-depth analysis on Erbium co-doped CdO:Zn films deposited by nebulizer method for opto-electronic applications.
- Author
-
Sarath babu, R., Narasimha murthy, Y., Shkir, Mohd, and AlFaify, S.
- Subjects
- *
ERBIUM , *AEROSOLS , *ENERGY dispersive X-ray spectroscopy , *HALL effect , *THIN films - Abstract
In the present study, we have analyzed the fabrication of transparent conductive Erbium (Er) co-doped CdO:Zn films by nebulizer spray method (NSP) by adding different Er level from 0 to 1.5 wt%. X-ray diffraction (XRD) pattern confirmed polycrystalline behavior of prepared Er co-doped CdO:Zn films of cubic crystalline system. Surface roughness of the films was slightly decreased from 20 nm to 16 nm. Elemental mapping and energy dispersive analysis of X-ray (EDX) spectra confirm the existence of Cd, O, Zn and Er in 1.5 wt% Er co-doped CdO:Zn film surface. The estimated optical transmittance and band gap value enhanced from 2.62 to 2.96 eV on growing Er doping concentrations. Photoluminescence (PL) spectrum emitted one strong near-band-edge (NBE) emission at ∼ 435 nm for all the Er co-doped CdO:Zn films, signify their better optical quality. Hall Effect measurements evidenced that the Er co-doping provides enhancement on the carrier concentration and reduce the electrical resistivity. The quality factor of Er co-doped CdO:Zn film thin film was increased from 1.1 × 10−4 (Ω−1) to 11.0 × 10−4 (Ω−1) for increasing the Er doping concentration from 0 to 1.5 wt%. AFM topograph, Tauc's plot for energy gap evaluation, PL spectra and resistivity, carrier concentration and mobility of Er co-doped CdO:Zn thin films prepared by NSP technique. Image 1 • Er co-doped CdO:Zn thin films were facilely fabricated by nebulizer spray pyrolysis technique. • X-ray diffraction study confirm monophasic cubic films fabrication. • Enhancement of energy gap was found from 2.62 to 2.96 eV by Er co-doping in CdO:Zn. • Resistivity of CdO:Zn films is changed from 9.77 × 10−3 to 7.2 × 10−4 Ωcm on Er doping. • Quality factor was increased from 1.1 × 10−4 to 11.0 × 10−4 Ω−1 on increasing of Er content. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
36. A low-cost vibrating sample magnetometry based on audio components.
- Author
-
Sankhi, Babu R. and Turgut, Emrah
- Subjects
- *
MAGNETIC anisotropy , *PERPENDICULAR magnetic anisotropy , *FREQUENCIES of oscillating systems , *MAGNETIC hysteresis , *ENGINEERING laboratories , *RESISTOR-inductor-capacitor circuits , *THIN films - Abstract
• Sound cards provide highly accurate analog to digital conversion at a lower cost. • Commercial sound cards provide measurements between 20 Hz and 3 kHz. • The sensitivity of sound-card-based magnetometry is 2 mirco-emu. • This sensitivity is comparable to commercial instruments. In this paper, we developed a low-cost, highly sensitive magnetization characterization instrument using a sound card and compared its sensitivity with commercially available measurement techniques. Firstly, we use an RLC circuit to measure the frequency-dependent response of the sound card and compare it with a lock-in amplifier. Then, we construct a simple but versatile measuring instrument, vibrating sample magnetometer (VSM) based on audio components, where data acquisition is performed by the sound card and the commercial lock-in amplifier. We test our magnetometry by measuring the magnetic hysteresis of three distinct samples: Nickel bulk piece, perm-alloy thin film with an easy-plane anisotropy, and Co/Pt multilayer with perpendicular magnetic anisotropy. We also analyze the magnetizations of three samples for different vibration frequencies and compare the sensitivities of two data acquisition methods. Although the sound card performs slightly worse than the lock-in amplifier at the vibration frequencies lower than 20 Hz due to the frequency cut-off, the sound card provides approximately seven times better sensitivity than the lock-in amplifier does at higher frequencies up to 60 Hz. We found that the sound card based VSM can have a sensitivity as high as 2 micro-emu at 34.7 Hz vibration frequency, which can be suitable for various laboratory and industrial applications. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
37. Development of thin-film metal hydrides for integration into field emission displays.
- Author
-
Chalamala, Babu R. and Reuss, Robert H.
- Subjects
- *
SOLID state physics , *THIN films , *HYDRIDES , *FIELD emission - Abstract
We report on the development of solid-state hydrogen sources utilizing thin-film metal hydrides. We demonstrate that integration of these metal hydride thin films facilitate a practical method to introduce controlled amounts of hydrogen into sealed field emission display assemblies. To prove the concept, we operated Mo field emitter arrays without emission current loss for 400 h of continuous operation with titanium-hydride-coated stainless steel anode plates. Comparable arrays operated in the absence of hydride films, but in ultrahigh vacuum, had emission current degradation of over 50% in less than 100 h of operation. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
38. Argon inclusion in sputtered films and the effect of the gas on molybdenum field emitter arrays.
- Author
-
Chalamala, Babu R. and Reuss, Robert H.
- Subjects
- *
ARGON , *SPUTTERING (Physics) , *THIN films - Abstract
Residual gas analysis of a number of field emission displays showed that argon desorbed from molybdenum metal lines was the dominant gas in sealed vacuum packages. We present experimental results on the emission characteristics of molybdenum field emitter arrays in argon ambient. In argon, the emission current dropped rapidly similar to that in oxygenic gas ambients. Existing degradation models do not provide an adequate explanation for this behavior. Rather, we suggest a model based on shallow implantation of argon into the field emitter tips that increases the effective width of the tunneling barrier. Experimental support for this model comes from the following observations: emission current degraded only when the device was turned on; after gas exposure, significant current recovery which followed diffusion type behavior was noted; degradation and recovery rates were functions of partial pressure; and no detectable effects associated with sputtering were observed. This mechanism is also consistent with ion pumping known to occur in field emission displays. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
39. Effect of growth conditions on surface morphology and photoelectric work function characteristics...
- Author
-
Chalamala, Babu R. and Yi Wei
- Subjects
- *
IRIDIUM , *THIN films - Abstract
Studies the effect of thermal growth conditions on the morphology and surface work function of iridium oxide thin films grown by annealing iridium thin films in an oxygen ambient. Photoelectric work function measurements; Thin film changes due to increasing temperature; Formation of iridium oxide accompanied by surface roughening.
- Published
- 1999
- Full Text
- View/download PDF
40. Electrical transport properties of spray deposited transparent conducting ortho-Zn2SnO4 thin films.
- Author
-
Ramarajan, R., Thangaraju, K., Babu, R. Ramesh, Joseph, D. Paul, Singh, Biswas, and Das
- Subjects
ZINC ,ELECTRODES ,OPTOELECTRONIC devices ,THIN films ,PYROLYSIS ,POLYCRYSTALS ,ORTHORHOMBIC crystal system - Abstract
Ortho Zinc Stannate (Zn
2 SnO4 ) exhibits excellent electrical and optical properties to serve as alternate transparent electrode in optoelectronic devices. Here we have optimized ortho-Zn2 SnO4 thin film by spray pyrolysis method. Deposition was done onto a pre-heated glass substrate at a temperature of 400 °C. The XRD pattern indicated films to be polycrystalline with cubic structure. The surface of films had globular and twisted metal sheet like morphologies. Films were transparent in the visible region with band gap around 3.6 eV. Transport properties were studied by Hall measurements at 300 K. Activation energies were calculated from Arrhenius’s plot from temperature dependent electrical measurements and the conduction mechanism is discussed. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
41. Optoelectronic, photocurrent sensitivity and photocatalytic dye degradation behaviour of spray deposited Cr doped SnO2 thin films.
- Author
-
Senthilkumar, P., Raja, S., Ramesh Babu, R., Kavinkumar, V., Jothivenkatachalam, K., and Vasuki, G.
- Subjects
- *
IRRADIATION , *THIN films , *PHOTODEGRADATION , *STANNIC oxide , *X-ray photoelectron spectroscopy , *MALACHITE green , *ZINC oxide films , *ELECTROMAGNETIC spectrum - Abstract
Undoped and SnO 2 :Cr doped thin films (Cr: 0.25, 0.50, 0.75 and 1 wt%) were deposited by economically home-made spray pyrolysis method. The characteristic behaviour of the deposited films was studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Photoluminescence (PL), Ultraviolet–visible (UV–vis.) spectroscopy, Current-Voltage (I–V) and photocatalytic studies. The XRD analysis confirms the tetragonal rutile structure of SnO 2 with predominant orientation along the (2 1 1) plane and the decrease in crystallite size from 48 to 30 nm by Cr-doping. The EDAX and XPS studies reveal the elements and its chemical state of Sn, O and Cr. The SnO 2 :Cr thin films exhibit an 85% average optical transmittance in the visible region of the electromagnetic spectrum. The SEM micrographs clearly show the well-defined grains with boundaries, and it is evident that grain size drastically reduces from 155 nm to 48 nm as a function of Cr-doping. Photoluminescence analysis confirms the defect-related emission (360 nm, 440 and 490 nm). The photocatalytic activity of all thin films is assessed using malachite green (MG) dye under UV light irradiation. 0.75 wt% Cr-doped SnO 2 film shows improved photocatalytic performance (60.37%) than undoped thin film (32.03%). The I–V characteristics of undoped and SnO 2 :Cr thin films are performed in visible light, showing photo-linear response behaviour. The highest figure of merit (FOM) obtained for SnO 2 :Cr (0.75 wt%) thin film is 7.07 × 10−6 Ω−1. The obtained values of the FOM and photocatalytic performance are discussed in the context of the suitability of these materials for transparent and conducting window materials in solar cells and photocatalytic degradation applications. [Display omitted] • SnO 2 :Cr thin films were coated by spray pyrolysis method. • The XRD results revealed that the average crystallite size of SnO 2 was decreased from 48 to 30 nm. • The PL analysis shows decreased recombination rate of photo-generated electrons and holes. • The high FOM (7.07 × 10−6 Ω−1) was achieved for 0.75 wt% Cr doping. • High degradation efficiency (60.37%) was obtained for 0.75 wt% Cr doping. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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42. Chemically sprayed CdO: Cr thin films for formaldehyde gas detection and optoelectronic applications.
- Author
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P, Velusamy, Liu, Xinghui, Ramesh Babu, R., Sathiya, M., Salem Alsaiari, Norah, Mohammed Alzahrani, Fatimah, Tariq Nazir, M., Elamurugu, Elangovan, and Zhang, Fuchun
- Subjects
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THIN films , *FIELD emission electron microscopes , *FORMALDEHYDE , *X-ray powder diffraction , *CARRIER density , *N-type semiconductors , *ZINC oxide films - Abstract
Chromium (Cr) doped CdO films are chemically sprayed and are characterized by their optical, electrical, structural, and microstructural characteristics. The thickness of the films is determined by spectroscopic ellipsometry. The cubic crystal structure with a superior growth along (111) plane of the spray-deposited films is confirmed from the powder X-ray diffraction (XRD) analysis. XRD studies also suggested that some of the Cd2+ ions were substituted by Cr3+ ions, and the solubility of Cr in CdO is minimal, to be around ∼0.75 wt%. The analysis by atomic force microscopy shows uniform distribution of grains throughout the surface, whose roughness is varied from 33 to 13.9 nm concerning Cr-doping concentration. The microstructures from the field emission scanning electron microscope reveal a smooth surface. The elemental composition is examined using an energy dispersive spectroscope. The micro-Raman studies carried out in room temperature endorse the presence of metal oxide (Cd–O) bond vibrations. Transmittance spectra are obtained using UV–vis–NIR spectrophotometer, and the band gap values are estimated from the absorption coefficient. The films show high optical transmittance (>75%) in vis-NIR region. A maximum optical band gap of 2.35 eV is obtained from 1.0 wt% Cr-doping. The electrical measurement (Hall analysis) confirmed the degeneracy nature and n-type semi-conductivity. The carrier density, carrier mobility, and dc-conductivity are increased for higher Cr-dopant percentage. High mobility (85 cm2V−1s−1) is observed for 0.75 wt% Cr-doping. The 0.75 wt% Cr-doping show a remarkable response to formaldehyde gas (74.39%). Figure Schematic diagram of preparation and formaldehyde gas sensing behaviour of Ti-doped CdO thin film. [Display omitted] • The thin films of Cr-doped CdO were deposited using a low-cost chemical spray pyrolysis equipment. • A high degree of formaldehyde gas responsivity (74.39%) is observed. • Obtaining a mobility of 85 cm2/Vs is considered to be quite high. • Transmission of 80% is achieved, along with an improved optical band gap of 2.39 eV. • The resulting merit figure is 343 × 10−5 Ω−1, which is rather high. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
43. Influence of substrate temperature on the structural, morphological, optical and electrical properties of copper telluride thin films prepared by electron beam evaporation method.
- Author
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Bhuvaneswari, P.V., Ramamurthi, K., and Ramesh Babu, R.
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ELECTRIC properties of thin films , *THIN films , *OPTICAL properties , *CRYSTAL morphology , *COPPER telluride , *SUBSTRATES (Materials science) , *STRUCTURAL analysis (Science) , *TEMPERATURE effect , *EVAPORATION (Chemistry) - Abstract
Copper telluride thin films were deposited on the glass substrates at different substrate temperatures viz., Room Temperature, 200, 300, 400 and 500 °C employing electron beam evaporation method. The effect of substrate temperature on the physical properties of copper telluride films was investigated. The X-ray diffraction pattern revealed that the films deposited at 300, 400 and 500 °C are polycrystalline in nature. The crystallite size, dislocation density and microstrain of these films were evaluated. Scanning electron microscopy images showed that the surface morphology of the films is modified by the variation in the substrate temperature. Further variation in the shape, size and distribution of the agglomerated crystallites formed on the surface of the copper telluride films and the roughness of the films were studied as a function of deposition temperature using atomic force microscopy. The direct optical band gap value of copper telluride films varies from 2.45 to 2.93 eV with variation in the substrate temperature. Positive sign of the Hall coefficient showed p -type conductivity. The copper telluride film deposited at 500 °C showed relatively low resistivity of 1.36 × 10 − 3 Ω cm. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
44. Influence of deposition distance and substrate temperature on the CdSe thin films deposited by electron beam evaporation technique.
- Author
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Mathuri, S., Ramamurthi, K., and Ramesh Babu, R.
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- *
CADMIUM selenide , *EVAPORATION (Chemistry) , *TEMPERATURE , *SUBSTRATES (Materials science) , *X-ray diffraction , *CRYSTAL growth - Abstract
Cadmium Selenide (CdSe) thin films were deposited on the microslide glass substrates by electron beam evaporation technique at source to substrate distance (D d ) of 10 cm and 15 cm and at different substrate temperatures (room temperature to 450 °C). The influence of D d and substrate temperature on the structural, optical and morphological properties of CdSe thin films was studied. X-ray diffraction studies revealed that CdSe films deposited at 10 cm and 15 cm and at different substrate temperatures possess hexagonal crystal system with preferential growth along (002) plane. Further the effect of D d and substrate temperature on the microstructural parameters such as crystallite size, strain, dislocation density and lattice constants was studied. CdSe films deposited at D d 10 cm and 15 cm and at 150 °C acquired low strain and dislocation density with respect to that of the other films. The optical transmittance of the film deposited at D d 10 cm and at 350 °C showed maximum transmittance of about 98% at 875 nm whereas the film deposited at D d 15 cm and at room temperature showed maximum transmittance of about 84% at 747 nm. Direct optical band gap energy of the films deposited at D d 10 cm is decreased with increase in substrate temperature. Scanning electron microscope studies revealed that the surface of the CdSe film deposited at D d 10 cm and at room temperature contains spherical shaped grains distributed on the surface and the surface becomes smooth with increase in substrate temperature. Surface of the film deposited at D d 15 cm and at room temperature showed fine grains with a few pinholes whereas the surface of the film deposited at 250 °C and 350 °C become rough with pinholes. Elemental analysis showed the presence of cadmium and selenium in the deposited thin films. Photoluminescence spectrum showed red emission band at ~ 740 nm for the films deposited at D d 10 cm and 15 cm and at room temperature, 150 °C and 450 °C. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
45. Influence of Ru doping on the structural, morphological, optical, electrical and optoelectronic properties of SnO2 thin films.
- Author
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Senthilkumar, P., Raja, S., Ramesh Babu, R., and Vasuki, G.
- Subjects
- *
THIN films , *TIN oxides , *ELECTRON transport , *ZINC oxide thin films , *SCANNING electron microscopy , *SOLAR cells , *RAMAN scattering - Abstract
Tin oxide (SnO 2) and various concentrations (1, 2, 3 and 4 wt%) of ruthenium (Ru)-doped tin oxide (SnO 2 :Ru) films were deposited on microscope glass slides using an economical laboratory-made spray pyrolysis method. The influence of Ru doping on the physical properties of SnO 2 films was studied using X-ray diffraction (XRD), UV–visible–near-infrared spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, photoluminescence (PL), micro-Raman spectroscopy and Hall measurement analyses. The XRD result corroborates that all the prepared films belong to tetragonal crystal structure with P 4 2 / mnm space group and reveals that crystallite size decreases from 29.06 to 22.41 nm. The 3 wt% Ru-doped SnO 2 film has a high average optical transmittance (88%) in the range of 400–1100 nm. The calculated optical band gap ranges within 3.50–3.76 eV. The SEM micrographs reveal the morphology changes and grain size decrement as a function of Ru doping. Metal oxide vibration (O–Sn–O) is confirmed using FT-IR and micro-Raman spectral analyses. The PL spectra measured at room temperature exhibit a strong blue emission at 420 nm for all films. All prepared thin films show resistivity of the order of 10−3 Ω cm. The highest figure of merit of 2.627 × 10−4 Ω−1 is obtained for 3 wt% of Ru doping in the wavelength range of 400–1100 nm. The present investigation clearly shows that the structural, optical, morphological, electrical and optoelectronic properties of SnO 2 thin films are effectively modified by the Ru dopant. Particularly, the 3 wt% of Ru-doped SnO 2 films could be useful for the electron transport layer in solar cells and other optoelectronic applications. [Display omitted] • SnO 2 :Ru films were prepared by economical laboratory-made spray pyrolysis method. • The crystallite size of SnO 2 film was decreased (29.06–22.44 nm) as a function of Ru doping. • A high optical transmittance of 88% (600–1100 nm) was observed for 3 wt% of Ru doping. • The optical band gap and resistivity valuesare significantly varied by Ru doping. • A high figure of merit value (2.627 × 10−4 Ω−1) was obtained for 3 wt% of Ru doping. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
46. An X-ray absorption near-edge structure (XANES) study of the Sn L3 edge in zirconium alloy oxide films formed during autoclave corrosion.
- Author
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Hulme, Helen, Baxter, Felicity, Babu, R. Prasath, Denecke, Melissa A., Gass, Mhairi, Steuwer, Axel, Norén, Katarina, Carlson, Stefan, and Preuss, Michael
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- *
X-ray absorption , *CRYSTAL structure , *ZIRCONIUM alloys , *THIN films , *AUTOCLAVES , *CORROSION & anti-corrosives - Abstract
Application of Sn L 3 -XANES to study the oxidation state of alloying additions of tin (1–1.2 wt%) in <2 μm oxide layers formed on nuclear grade zirconium alloy has been demonstrated. Data obtained for metallic and corroded ZIRLO™ (1 wt% Sn) and Zircaloy-4 (1.2 wt% Sn) indicate tin has a similar chemical speciation in both metal alloys but this differs in the oxidised surface layers. By recording XANES at various incident angles to vary the photon penetration depth and amount of the oxide layer probed in the measurement, the authors found evidence that the oxidation of tin progresses with increasing oxide thickness. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
47. Effect of fluorine doping on the structural, optical and electrical properties of spray deposited cadmium stannate thin films.
- Author
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Bhuvaneswari, P.V., Velusamy, P., Babu, R. Ramesh, Babu, S. Moorthy, Ramamurthi, K., and Arivanandhan, M.
- Subjects
- *
FLUORINE , *DOPING agents (Chemistry) , *OPTICAL properties , *ELECTRIC properties , *CADMIUM stannate , *THIN films - Abstract
Cadmium stannate (Cd2SnO4) thin films were coated on Corning 1737 glass substrates at 540°C by spray pyrolysis technique, from the aqueous solution of cadmium acetate and tin (II) chloride precursors. Fluorine doped Cd2SnO4 (F: Cd2SnO4) thin films were prepared by adding ammonium fluoride in the range of 0–5wt% of the total weight of cadmium acetate and tin (II) chloride in the spray solution. Thickness of the prepared films is about 300nm. X-ray diffraction analysis of the Cd2SnO4 and 3wt% F: Cd2SnO4 films shows the signature for the growth along (222) direction. Scanning electron micrographs showed that fluorine doping effectively modifies the surface morphology of Cd2SnO4 films. Average optical transmittance in the visible region (500–850nm) for Cd2SnO4 is ~79% and it is increased to ~83% for 1wt% doping concentration of the NH4F in the solution. Fluorescence spectra of F: Cd2SnO4 (1wt% and 3wt%) exhibit peak at 601nm. F: Cd2SnO4 film (1wt%) shows mobility of ~42cm2/Vs, carrier concentration of ~9.5×1019 cm−3 and resistivity of ~1.5×10−3 Ωcm. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
48. Enhanced electrical and optoelectronic properties of W doped SnO2 thin films.
- Author
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Senthilkumar, P., Raja, S., Ramesh Babu, R., and Vasuki, G.
- Subjects
- *
OPTOELECTRONICS , *ENERGY dispersive X-ray spectroscopy , *X-ray photoelectron spectroscopy , *CARRIER density , *TIN oxides - Abstract
In the present study, undoped tin oxide (SnO 2) and tungsten (W) doped tin oxide (1, 2, 3, 4 and 5 wt% of W doping) thin films were deposited by the homemade spray pyrolysis technique and their structural, microstructural, optical, electrical, and optoelectronic properties are described. X-ray diffraction analysis confirmed that all the prepared thin films belonged to a tetragonal crystal structure with a space group of P4 2 / mnm. The elemental oxidation state of Sn4+, O2− and W6+ was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis. The scanning electron microscopy revealed that the surface morphology of SnO 2 thin films was slightly modified by W doping. The presence of Sn, O and W and their elemental compositions were confirmed using the energy dispersive X-ray spectroscopy. The 3 wt% of W doped SnO 2 (SnO 2 :W) thin films showed maximum optical transmittance of about 90% in the visible and NIR region. The direct optical bandgap varied between 3.60 eV and 3.84 eV. Photoluminescence spectra showed noticeable enhancement in the UV emission peak at 362 nm and green emission peak at 525 nm of SnO 2 :W thin films. The high charge carrier concentration of 2.89 × 1020 cm−3 was observed for 3 wt% of W doping. The Hall mobility of the undoped SnO 2 thin films was found to be 94 cm2/Vs. A high figure of merit of 8.30 × 10−3 Ω−1 was obtained for the thin films doped with 3 wt% of W. [Display omitted] • The lowest resistivity (1.26 × 10−3 Ω cm) was obtained for 3 wt% of W doping. • Carrier concentration is increased from 1.72 × 1019 cm−3 to 2.89 × 1020 cm−3 for increasing W doping. • The average optical transmittance (90%) was obtained in the wavelength region of 500 nm–800 nm. • The high figure of merit (8.30 × 10−3 Ω−1) was obtained for 3 wt% of W doping. • 3 wt% of W doped SnO 2 thin film may be useful for opto-electronic device applications. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
49. Activation behavior and dielectric relaxation in polyvinyl alcohol and multiwall carbon nanotube composite films
- Author
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Chakraborty, G., Meikap, A.K., Babu, R., and Blau, W.J.
- Subjects
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DIELECTRIC relaxation , *POLYVINYL alcohol , *CARBON nanotubes , *COMPOSITE materials , *THIN films , *ELECTRIC conductivity - Abstract
Abstract: The dc and ac electrical transport property of Polyvinyl Alcohol-Multiwall Carbon Nanotubes (PVA-MWNT) composites has been investigated within a temperature range and in the frequency range 20Hz–1MHz. The temperature variation of dc conductivity gives the presence of two different activation energies. The dielectric properties of the samples have been explained in terms of electric modulus vector.The dielectric relaxation has been explained in terms of interfacial polarization occurring in between the insulating PVA matrix and MWNT conductive filler. The variation of the relaxation time with temperature also indicates the presence of two different activation energies. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
50. A study on formaldehyde gas sensing and optoelectronic properties of Bi-doped CdO thin films deposited by an economic solution process.
- Author
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Velusamy, P., Xing, Ruimin, Babu, R. Ramesh, Elangovan, E., Viegas, J., Liu, Shanhu, and Sridharan, M.
- Subjects
- *
PYROLYTIC graphite , *BISMUTH , *THIN films , *METAL oxide semiconductors , *OPTICAL films , *FORMALDEHYDE , *TRANSITION metal ions - Abstract
• Bi-doped CdO thin films were deposited by a cost-effective pyrolytic spray process. • Sensitive formaldehyde response was observed for 0.75 wt. % Bi-doped CdO with satisfactory stability. • Above 80% of the transmittance in visible and NIR region was obtained from all the Bi-doped CdO. • Figure of merit (4.56 × 10−3 Ω-1) obtained from 0.50 wt. % Bi-doped CdO is superior than the previous reported. • Enhanced carrier mobility (78 cm2/V s) was obtained from 0.25 wt. % Bi-doped CdO thin film. Doped metal oxide semiconductors have received greater attention for the development of gas sensor, working at low temperature, as well as of optoelectronics. In this work, a post transition metal ion of bismuth (Bi) doped cadmium oxide (CdO) thin films were deposited by a cost-effective pyrolytic spray process at substrate temperature of 300 °C. The effects of Bi-doping concentrations on the microstructural, gas sensing and optoelectronic properties of CdO thin films are systematically studied. The CdO film doped with 0.75 wt% of Bi exhibits high response (86.20%) to formaldehyde at a low operating temperature of 130 °C with satisfactory stability, selectivity and anti-interference to humidity. The response mechanism to formaldehyde is discussed in details. Optical results indicate that an improved transmittance above 80% in visible and NIR region was observed for all the Bi-doped CdO thin films with an enhanced optical band gap, in comparison with undoped CdO. Photoluminescence study indicates the presence of optical defects such as neutral donors and deep centers in CdO thin films. The high figure of merit value (4.56 × 10−3 Ω-1) obtained from 0.50 wt% of Bi-doped CdO is superior to the previously reported. The improved carrier mobility (78 cm2/V⋅s) is obtained from 0.25 wt% of Bi-doped CdO thin film. The present investigation indicated that the Bi-doped CdO thin films would be an attractive candidate for formaldehyde gas sensing and optoelectronic applications. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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