Au-Si Interface Photodetector

• 08 May 2020

Why in News

Recently, scientists from the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) have fabricated a wafer-scale photodetector (thin slice-based) device, using gold-silicon interface.

• JNCASR is an autonomous institute under the Department of Science and Technology (DST).

Key Points

• The scientists have fabricated gold (Au)-silicon (n-Si) interface, which shows high sensitivity towards light demonstrating the photodetection action.
  
  • The Au-Si interface was brought about by galvanic deposition (a technique for electroplating of metals) wherein water-based solutions (electrolytes) are used, which contain the metals to be deposited as ions.
  • A nanostructured Au film was deposited on top of p-type silicide (compound that has silicon with more electropositive elements), which acts as a charge collector.
• The metal nanostructures enhance the performance of the fabricated detector through trapping the incoming light.
• The detector exhibits a rapid response of 40 microseconds and can detect low light intensities.
• The device covers a broad spectral range from Ultraviolet to Infrared and shows excellent uniformity throughout the entire active area with less than 5% variation in response.
• Photodetectors:
  
  • These are an important part of an optoelectronic circuit that can detect light.
  • These are employed for a wide variety of applications like:
    
    • Controlling automatic lighting in supermarkets.
    • Detecting radiation from the outer galaxy.
    • Being used in security-related applications.
  • However, due to high material cost and the intricate fabrication processes, photodetectors become unaffordable for daily applications.

Advantages of Au-Si interface Photodetector

• Quick & Simple: The process of fabricating a detector takes only a few minutes, making it a quick and simple process.
• Cost-effective: Being a solution-based technique, the method is highly economical and enables large-area fabrication without compromising the detector response.
• Highly Capable: The device can help detect weak scattered light as an indication of unwanted activity.
• Energy Efficient: The detector operates in self-powered mode, which means the device does not require external power for its operation.
• Environmentally Stable: With a commonly available protective coating, the device shows a long-term environmental stability, under harsh conditions.
• Multiple Usage: It can also be used as a prototype imaging system, lux and power meter and as a tool for security applications.

Source: PIB