K. S. Gour; A. K. Yadav; Rahul Kumar; J. S. Tawale; V. N. Singh
Abstract
Zinc oxysulfide or Zn(O,S) is emerging as an alternate n-type buffer layer for kesterite, chalcogenides and CdTe based thin film solar cell due to it is being made from non-toxic elements and tunable bandgap, its suitable optical and electrical properties required for a buffer layer. Generally, buffer ...
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Zinc oxysulfide or Zn(O,S) is emerging as an alternate n-type buffer layer for kesterite, chalcogenides and CdTe based thin film solar cell due to it is being made from non-toxic elements and tunable bandgap, its suitable optical and electrical properties required for a buffer layer. Generally, buffer layers of these solar cells are deposited using chemical bath deposition (CBD) techniques, but these require breaking of vacuum and again inserting the sample in vacuum during solar cell fabrication, which is not economical and is cumbersome. Sputtering is considered to be industrial process and therefore, here we have deposited Zn(O,S) thin film by sputtering technique and effect of sulfurization temperature on bandgap and composition of Zn(O,S) films have been studied. The bandgap of deposited films changed from 3.36 eV to 3.15 eV by changing the sulfurization temperatures. By changing the sulfurization temperature, the composition of films also changed. Crystallite size (D) of Zn(O,S) films increased from 12.1 nm to 22.3 nm by varying the sulfur content for samples S1-S4, respectively. Optical, morphological, compositional and structural properties have been studied using UV-Vis-NIR spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS) and X-ray diffractometer (XRD), respectively.
Pankaj Srivastava; Yamini Sharma
Abstract
Transparent conducting oxide CdO has a wide range of applications in optoelectronics. We present the results of electronic and optical properties of pure and transition metal ions Sc, Y and Ti-doped CdO. The electronic structure is calculated within the full-potential linearized augmented plane wave ...
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Transparent conducting oxide CdO has a wide range of applications in optoelectronics. We present the results of electronic and optical properties of pure and transition metal ions Sc, Y and Ti-doped CdO. The electronic structure is calculated within the full-potential linearized augmented plane wave (LAPW) + local orbitals (lo). The calculated band gap for pure CdO is 0.51 eV and changes significantly with doping. The calculated bandgap for Sc-doped CdO (CSO) is 2.67 eV, for Y-doped CdO (CYO) is 2.93 eV, and for Ti-doped CdO (CTO) is 2.53 eV. The effect of doping is clearly seen in the optical absorption profiles as well as in the enhanced electrical conductivities. Due to the widened optical transparency window, doped TCO has nearly 75-80% transmittance in the optical region. There is possibility of greater multiple direct and indirect interband transitions due to availability of more states compared to pure CdO.
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