4 results on '"Yadav, Satyesh Kumar"'
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2. Annealing-induced changes in optoelectronic properties of sputtered copper oxide films.
- Author
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Koshy, Aarju Mathew, Sudha, A., Gollapalli, Prince, Yadav, Satyesh Kumar, and Swaminathan, Parasuraman
- Subjects
COPPER oxide films ,COPPER oxide ,SOLAR cell design ,REACTIVE sputtering ,MAGNETRON sputtering ,OXIDE coating ,THIN films - Abstract
Copper (I) oxide thin films are deposited on quartz substrates by DC magnetron reactive sputtering. This study examines the effect of post-annealing on their optoelectronic properties in detail. The films are grown by sputtering from copper in an atmosphere of argon and oxygen. The substrate temperature is held at 200 °C, while annealing in ambient atmosphere has been carried out between 100 and 600 °C. X-ray diffraction analysis, Raman and UV–Vis spectroscopy, and four-probe measurements were used to characterise the films. XRD indicates that deposited Cu
2 O has a preferred orientation of (110). Post-annealing did not show any measurable conversion to copper (II) oxide until about 500 °C, and the process was incomplete even at 600 °C. The highest conductivity is observed in the sample post-annealed at 100 °C. These results are of substantial technological importance for using Cu2 O for a variety of applications, including transparent solar cell fabrication. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
3. Effect of substrate temperature on the optical properties of DC magnetron sputtered copper oxide thin films.
- Author
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Koshy, Aarju Mathew, Sudha, A., Yadav, Satyesh Kumar, and Swaminathan, Parasuraman
- Subjects
- *
COPPER oxide films , *COPPER oxide , *DC sputtering , *OPTICAL properties , *SOLAR cell design , *MAGNETRON sputtering - Abstract
Copper oxide thin films are deposited on quartz substrates by DC magnetron sputtering and the effect of deposition temperature on the optical properties is examined in detail. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) analysis, Raman spectroscopy, UV–vis spectroscopy, and four-probe sheet resistance measurements are used to characterize the surface morphology, structural, optical, and electrical properties of the deposited films respectively. Sputter deposition is carried out with the substrate at room temperature and at elevated temperatures between 200 and 300 °C. XRD analysis indicates that the oxide formed is primarily Cu 2 O and the absorption spectra show a critical absorption edge at around 300 nm. The sheet resistance gradually decreases with increase in deposition temperature, corresponding to an increase in the conductivity of the films. Also observed is an increase in the band gap energy from 2.02 eV for room temperature deposition to 2.35 eV at 300 °C, corresponding to an improved film crystallinity and reduction in defect density. The band gap energy and the variation of sheet resistance with substrate temperature shows that the microstructure plays a vital role in their behavior. These transformation characteristics are of huge technological importance having variety of applications including transparent solar cell fabrication. • Copper oxide thin films were deposited on quartz substrates at different substrate temperatures. • The properties significantly depend on the substrate temperature. • Highly stable single phase of Cu 2 O (110) is reported for the first time using this method. • The material has huge technological importance and can be used for integration of the material for the device fabrications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Improving the photoresponse of magnetron sputtered titania films by optimizing substrate and electrode configuration.
- Author
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Sudha, A., Ashok, Allamula, Patil, Sanjeev, Yadav, Satyesh Kumar, and Swaminathan, P.
- Subjects
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MAGNETRON sputtering , *PARTICLE size distribution , *DC sputtering , *TITANIUM dioxide , *TIN oxides , *ZINC oxide films , *RUTILE - Abstract
Titania (TiO 2) is a natural choice for photocatalysts and photodetectors due to its superior properties such as high stability and high photoelectric effect coupled with low cost fabrication routes. In this work we study the effect of substrate on the structural, morphological, and photoresponse behavior of sputtered titania thin films. We also compare the difference in photoresponse between parallel and series electrode configurations to understand the role of configuration on the design of photodetectors. TiO 2 films of 50 nm thickness are sputtered onto three different substrates, namely quartz, fluorine-doped tin oxide (FTO), and silicon (Si) using direct current reactive magnetron sputtering. The structural and optical properties, along with photoresponse behavior, on these three different substrates are investigated. The sputtered TiO 2 film crystallizes in the rutile structure with a uniform grain size distribution. Analysis of the transmittance data from UV–Vis spectra was used to derive the optical constants for the film. The sensitivity of TiO 2 to photoresponse is highly dependent on the substrate. The response is better for Si substrate, when compared to FTO or quartz and this is due to the heterojunction formation at the TiO 2 /Si interface. Sensitivity, responsivity, and detectivity are also obtained for both parallel and series electrode configuration for Si substrate and better photoresponse is exhibited by the parallel configuration since carrier recombination in the bulk of the Si wafer is avoided. The photocurrent values in this work are an order of magnitude better than previous work on TiO 2 /Si, while the slightly slower response times maybe attributed to the strain-induced barrier reduction and band bending. Thus, this work showcases the tailoring of optoelectronic devices based on magnetron sputtered titania thin films by choosing appropriate substrates and electrode geometries. [Display omitted] • Titania thin films are deposited on different substrates using DC magnetron sputtering for photodetector application. • Superior photoresponse is exhibited by sputtered TiO 2 /p-Si heterojunction. • TiO 2 /Si parallel configuration shows enhanced photocurrent of 179 μ A. • Variation in photoresponse between series and parallel geometry on Si substrates for TiO 2 reported for the first time. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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