Journal of Materials Science: Materials in Electronics

, Volume 30, Issue 23, pp 20687–20695 | Cite as

Improvement of UV photodetector properties of reactively sputtered TiO2−x films through vacuum annealing

  • Y. Ashok Kumar ReddyEmail author
  • B. Ajitha
  • Maddaka Reddeppa
  • Adem Sreedhar


We present the influence of vacuum annealing on RF magnetron-sputtered TiO2−x thin films grown at various oxygen partial pressures (\(p_{{{\text{O}}_{2} }}\)) of 2.0%, 4.0% and 6.0% to enhance the ultra-violet (UV) photodetector performance. Apart from the film deposited at 2.0% of \(p_{{{\text{O}}_{2} }}\), all the as-grown TiO2−x films show an amorphous nature, whereas thermally annealed TiO2−x films at 400 °C show the rutile phase. As revealed by the linear current–voltage characteristics, the ohmic-contact behavior was observed between the TiO2−x layer and the electrode material. Benefiting from the above features, the photocurrent was significantly increased at 4.0% of \(p_{{{\text{O}}_{2} }}\) due to the increase of oxygen vacancies and the suppression of electron–hole recombination. As a result, thermally annealed TiO2−x films are very useful for next-generation UV-photodetectors even at a lower power density of 1.72 mW/cm2. Therefore, the merits of the above findings present a promising strategy to enhance the UV photoresponse of thermally annealed TiO2−x films by optimizing the \(p_{{{\text{O}}_{2} }}\) at 4.0%.



One of the authors, Dr. Y. Ashok Kumar Reddy, acknowledges the Department of Science and Technology (DST), New Delhi, India, for the award of DST-Inspire Faculty (DST/INSPIRE//04/2017/002531).


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of PhysicsIndian Institute of Information Technology, Design and Manufacturing, KancheepuramChennaiIndia
  2. 2.Department of Nano-Structured Materials ResearchNational Nano-Fab Center (NNFC) at KAISTDaejeonRepublic of Korea
  3. 3.Department of PhysicsChungnam National UniversityDaejeonRepublic of Korea
  4. 4.Department of Nano-PhysicsGachon UniversitySeongnam-siRepublic of Korea

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