Abstract
<title>Abstract</title> <p>Porous silicon (PS) formation for surface passivation and antireflection coating (ARC) plays a critical role in enhancing the performance of silicon solar cells. However, conventional wet-chemical and anodization-based methods are resource-intensive and environmentally burdensome. In this work, a scalable multi-wafer acidic vapor-phase etching mixture (AV-PEM) process is introduced as a high-throughput, dry-chemical alternative for PS fabrication. The proposed non-contact approach employs an HF/HNO₃ vapor environment within a closed reactor to induce a cyclic oxidation–dissolution mechanism, forming a nanoporous silicon layer with a graded refractive index while preserving metallic contacts. PS layers were fabricated on both multicrystalline silicon wafers (mc-Si-W) for structural and optical characterization, and multicrystalline silicon solar cells (mc-Si-SC) for electrical evaluation using current–voltage (I–V) and light-beam-induced current (LBIC) measurements. The VPE-treated devices exhibit a significant reduction in reflectivity from 25% to 8–12%, leading to enhanced light absorption and an increase in short-circuit current density (Jsc) up to 28.61 mA/cm². In addition, improved surface and grain boundary passivation, attributed to Si–Hₓ bond formation, results in a higher shunt resistance (~ 780 Ω) and reduced recombination losses. Consequently, the power conversion efficiency improves from 8.80% to 11.50%. Beyond performance gains, the AV-PEM process offers substantial environmental advantages by reducing chemical consumption, eliminating liquid waste, and enabling simultaneous multi-wafer processing. These findings demonstrate that vapor-phase-etched porous silicon is a promising, eco-efficient, and scalable solution for next-generation high-performance silicon solar cells.</p>