Self-powered broadband photodetector based on a solution-processed p-NiO/n-CdS:Al heterojunction

Area of Science:

• Materials Science
• Optoelectronics
• Device Physics

Background:

• Solution-processed photodetectors offer integration advantages and tunable performance.
• There is a high demand for self-powered photodetectors for sensing, imaging, and communication applications.

Purpose of the Study:

• To develop a novel self-powered photodetector using a solution-processed p-NiO/n-CdS:Al heterojunction.
• To investigate the photodetection capabilities and photovoltaic behavior of the fabricated device.

Main Methods:

• Fabrication of CdS:Al thin films on ITO substrates via chemical bath deposition.
• Development of NiO thin films using the sol-gel route.
• Characterization of optical absorption and photoresponse properties.

Main Results:

• The p-NiO/n-CdS:Al heterojunction exhibited a high current rectification ratio (3 orders in dark) and photovoltaic behavior.
• The device demonstrated effective UV-visible photodetection due to complementary absorption of NiO (UV) and CdS:Al (visible).
• Achieved photoresponsivity of 55 mA/W (UV) and 30 mA/W (visible) with fast response speeds at zero bias.

Conclusions:

• The developed heterojunction functions as a self-powered photodetector, driven by the photovoltaic effect.
• The solution-processing and fabrication method enable compatibility with various materials and flexible substrates.
• The device shows significant potential for applications in photodetectors, optoelectronic devices, and sensors.