Numerical evaluation and optimization of high sensitivity Cu₂CdSnSe₄ photodetector

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Photodetectors (PDs) are crucial optoelectronic devices.
• Copper cadmium tin selenide (Cu2CdSnSe4) is a promising material for PD applications.
• Optimization of PD performance is essential for advanced applications.

Purpose of the Study:

• To explore the performance of Cu2CdSnSe4 based photodetectors.
• To investigate the effect of a back surface field (BSF) layer on PD performance.
• To optimize physical attributes for enhanced photodetector characteristics.

Main Methods:

• Utilized the solar cell capacitance simulator (SCAPS-1D) for device simulation.
• Employed cadmium sulfide (CdS) as a window layer and molybdenum disulfide (MoS2) as a BSF layer.
• Adjusted physical parameters including width, carrier density, and bulk defects.

Main Results:

• Optimized Cu2CdSnSe4 PD without BSF achieved V_OC of 0.76 V, J_SC of 45.57 mA/cm2, responsivity of 0.72 A/W, and detectivity of 5.05 × 10^14 Jones.
• Insertion of MoS2 BSF layer improved V_OC to 0.84 V.
• The BSF layer significantly enhanced responsivity to 0.84 A/W and detectivity to 2.32 × 10^15 Jones.

Conclusions:

• The MoS2 BSF layer substantially improves the performance of Cu2CdSnSe4 photodetectors.
• The enhanced built-in potential due to the BSF layer is key to performance improvement.
• Cu2CdSnSe4 based photodetectors show significant future potential for optoelectronic applications.