Simplified chemical processed Cd_1-AlS thin films for high-performance photodetector applications

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Cadmium sulfide (CdS) is a semiconductor with potential for photodetector applications.
• Enhancing CdS photoelectric properties is crucial for improved device performance.
• Aluminum (Al) doping is explored as a method to tune CdS characteristics.

Purpose of the Study:

• To investigate the impact of aluminum (Al) doping on the photoelectric performance of cadmium sulfide (CdS) thin films.
• To optimize Al doping concentration for enhanced photodetector characteristics.
• To evaluate the potential of Al-doped CdS as a material for scientific and industrial photodetector applications.

Main Methods:

• Thin films of CdS doped with varying Al concentrations (1-9 at.%) were prepared using an automatic nebulizer spray method.
• X-ray diffraction (XRD) was used to analyze crystal structure and crystallite size.
• Optical absorption, photoluminescence (PL) spectroscopy, and photoelectric measurements were conducted.

Main Results:

• XRD confirmed a hexagonal crystal structure with increased crystallite size upon Al doping.
• An impurity phase (CdO) was observed, potentially contributing to enhanced photo-generation.
• The minimum bandgap of 2.28 eV and maximum visible light absorption were achieved at 6 at.% Al.
• Photoluminescence showed increased near-band-edge emission and red emission at 635 nm.
• The optimized CdS:Al film exhibited high responsivity (8.64 AW⁻¹), external quantum efficiency (~2018%), and detectivity (9.29 × 10¹¹ Jones).

Conclusions:

• Aluminum doping effectively enhances the photoelectric performance of CdS thin films.
• The optimal Al concentration of 6 at.% yields superior photodetector characteristics.
• CdS:Al films demonstrate significant improvements over existing literature, presenting a viable material for advanced photodetector applications.