High-Responsivity UV-Blue Photodetector Based on Nanostructured CdS and Prepared by Solution Processing

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Conventional silicon photodetectors have limited sensitivity to short-wavelength light due to their narrow indirect bandgap.
• Ultraviolet (UV) and blue-light photodetectors are crucial for environmental monitoring, medical applications, and security technologies.

Purpose of the Study:

• To investigate the effect of precursor concentration on CdS nanostructure properties.
• To fabricate and characterize a high-performance UV photodetector using CdS nanostructures and CuSCN.

Main Methods:

• Chemical bath deposition was used to synthesize CdS thin films with varying precursor concentrations.
• A p-n heterojunction photodetector was fabricated by integrating spin-coated CuSCN with optimized CdS nanostructures.

Main Results:

• The optimal CdS precursor concentration of 2 M yielded the best photoresponsivity (21.1 mA/W).
• The fabricated CdS/CuSCN heterojunction photodetector exhibited a high rectification ratio (~750) and low ideality factor (1.39).
• The device achieved exceptional UV responsivity exceeding 10^4 A/W, significantly outperforming traditional CdS devices.

Conclusions:

• CuSCN incorporation and heterojunction formation enhance light absorption, charge separation, and hole transport.
• This study presents a cost-effective, solution-processed method for high-responsivity nanostructured photodetectors.
• The developed photodetectors show promise for smart healthcare, environmental surveillance, and consumer electronics.