JNCASR scientists fabricate energy-efficient photodetector for security application

  • Scientists from Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) have fabricated an economical and energy-efficient wafer-scale photodetector (thin slice-based).
  • This invention was published in the journal Applied Electronic Materials of the American Chemical Society as it provides a simple and cost-effective solution-based fabrication method for high-performance photodetector.


  • This has been made using gold – silicon interface, for security applications.
  • It could help detect weak scattered light as an indication of unwanted activity.
  • The scientists have fabricated gold (Au)– silicon (n-Si) interface, which showed high sensitivity towards light demonstrating the photodetection action.
  • In addition, a nanostructured Au film also was deposited on top of p-type silicide (having an excess of positive charges), which acts as a charge collector.
  • Being a solution-based technique, the method is highly economical and enabled large-area fabrication without compromising the detector response.
  • The process is quick, taking only minutes to fabricate a detector of any arbitrary area.
  • The metal nanostructures enhanced the performance of the fabricated detector through trapping the incoming light.
  • This photodetector displayed long-term environmental stability.
  • The detector exhibits a rapid response of 40microseconds and can detect low light intensities


  • Photodetectors are the heart of any optoelectronic circuit that can detect light.
  • They are employed for a wide variety of applications ranging from controlling automatic lighting in supermarkets to detecting radiation from outer galaxy as well as security-related applications.
  • The material cost and the intricate fabrication processes involved in realizing high-performance detectors make them unaffordable for day to day applications.


  • The scientists also demonstrated the photodetector’s utility as a prototype imaging system, lux and power meter, and also as a tool for security applications.
  • In the prototype, inside the model house, a fabricated detector was mounted beside a high-value commercial detector for comparison and connected to same external circuit to trigger warning lights (blue lights in the image) and security buzzer.
  • The door is opened to allow only weak scattered light as a sign of unwanted activity.
  • With such low level of lighting, not detectable by the human eye, the fabricated detector was activated, turning on the buzzer and the lights.


  • Established by the Department of Science and Technology of the Government of India, to mark the birth centenary of Pandit Jawaharlal Nehru.
  • Founder-CN Rao
  • Location-Bangalore
  • Established-1989

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