• K A Vanaja

      Articles written in Bulletin of Materials Science

    • Effect of oxygen intercalation on properties of sputtered CuYO2 for potential use as 𝑝-type transparent conducting films

      R Manoj M Nisha K A Vanaja M K Jayaraj

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      Transparent films of copper yttrium oxide doped with 2% calcium have been prepared by rf magnetron sputtering. The films show a conductivity of 8 Scm-1 on intercalation of oxygen at high pressure, which reduced the transparency in the visible region. The Ca-doped CuYO2 films before oxygen intercalation show an average transmission of about 60% which reduces to about 45% upon oxygen intercalation. The temperature dependence of the conductivity indicates semiconductor behaviour with low activation energy of 0.59 eV at room temperature. The positive sign of Seebeck coefficient (+274 𝜇VK-1) confirms the 𝑝-type conductivity of the films. The optical bandgap of CuYO2 was found to be 3.15 eV.

    • 𝑝-AgCoO2/𝑛-ZnO heterojunction diode grown by rf magnetron sputtering

      K A Vanaja Umananda M Bhatta R S Ajimsha S Jayalekshmi M K Jayaraj

      More Details Abstract Fulltext PDF

      𝑃-type transparent semiconducting AgCoO2 thin films were deposited by rf magnetron sputtering of sintered AgCoO2 target. The AgCoO2 films grown by rf sputtering were highly 𝑐-axis oriented showing only (001) reflections in the X-ray diffraction pattern unlike in the case of amorphous films grown by pulsed laser deposition (PLD). The bulk powder of AgCoO2 was synthesized by hydrothermal process. The optical bandgap was estimated as 4.15 eV and has a transmission of about 50% in the visible region. The temperature dependence of conductivity shows a semiconducting behaviour. The positive sign of Seebeck coefficient (+220 𝜇VK–1) indicates 𝑝-type conductivity. Transparent 𝑝–𝑛 heterojunction on glass substrate was fabricated by rf magnetron sputtering of 𝑝-AgCoO2 and 𝑛-type ZnO : Al thin films. The structure of the diode was glass/ITO/𝑛-ZnO/𝑝-AgCoO2. The junction between 𝑝-AgCoO2 and 𝑛-ZnO was found to be rectifying.

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    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

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      Posted on July 25, 2019

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