Modeling of Ag₃AuS₂-based NIR photodetector with BaSi₂ BSF layer for superior detectivity

This study presents a high-performance Ag 3 AuS 2 photodetector design optimized for near-infrared (NIR) detection by integrating an n -ZnTe window layer and p + -BaSi 2 as back surface field (BSF) layer. The n -ZnTe window layer enables efficient light penetration and reduced surface recombination. Through a series of simulations, the inclusion of the p + -BaSi 2 layer has delineated to markedly improve key metrics, including open-circuit voltage V OC at 0.9 Volt, short-circuit current density J SC at 40.4 mA/cm 2 , with minor dark current J 0 of 3.48 × 10 −14 mA/cm -2 , responsivity (R) reaching 0.71 AW -1 , and detectivity (D*) achieving 6.74 × 10 15 Jones. The BSF layer enhances efficiency by reducing surface recombination and dark current, leading to improved carrier mobility and reduced leakage currents. Additionally, by optimizing the Ag 3 AuS 2 layer’s thickness, doping, and flaw density, the device displays outstanding responsivity and detectivity in the NIR spectrum, demonstrating its robustness and suitability for advanced photo-detection applications. The results suggest that the ZnTe/Ag 3 AuS 2 /BaSi 2 structure provides a competitive and sustainable solution for efficient NIR detection which may position it as a strong alternative to existing PD designs.