In this study, we investigated and compared the influence of alumina nanoparticles (Al-NPs) and silicon nitride (SiN_x) layers individually deposited on multi-crystalline silicon (mc-Si) on mc-Si’s structural, optical, and optoelectronic characteristics to improve surface quality. Alumina nanoparticle-covered multi-crystalline silicon, immersion in HF/H₂O₂/HNO₃, and porous silicon (PS) covered with a silicon nitride structure are key components in achieving high electronic quality in multi-crystalline silicon. Surface reflectivity decreased from 27% to a minimum value of 2% for alumina nanoparticles/PS and a minimum value of 5% for silicon nitride/PS at a wavelength of 930 nm. Meanwhile, the minority carrier diffusion length increased from 2 µm to 300 µm for porous silicon combined with silicon nitride and to 100 µm for alumina nanoparticles/porous silicon. Two-dimensional current mapping further demonstrated a considerable enhancement in the generated current, rising from 2.8 nA for untreated mc-Si to 34 nA for Al-NPs/PS and 66 nA for PS/SiN_x. These results confirm that the surface passivation of mc-Si using Al-NPs or PS combined with SiN_x is a promising and efficient method to improve the electrical quality of mc-Si wafers, contributing to the development of high-performance mc-Si-based solar cells.

Surface texturing is vital for enhancing light absorption and optimizing the optoelectronic properties of multicrystalline silicon (mc-Si) samples. Texturing significantly improves light absorption by minimizing reflectance and extending the effective path length of incident light. Furthermore, porous silicon treatment on textured mc-Si surfaces offers additional advantages, including enhanced carrier generation, reduced surface recombination, and improved light emission. In this study, a dual treatment combining porous silicon and texturing was employed as an effective approach to enhance the optical and optoelectronic properties of mc-Si. Both porous silicon and texturing were achieved through a chemical etching process. After these surface modifications, the morphology and structure of mc-Si were examined using Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), UV-Vis-IR spectroscopy, photoluminescence (PL), WCT-120 photo-conductance lifetime measurements, and Two-Internal Quantum Efficiency (IQE) analysis. The results reveal a substantial improvement in the material’s properties. The total reflectivity dropped from 35% to approximately 5%, while the effective minority carrier lifetime increased from 2 µs for bare mc-Si to 36 µs after treatment. Additionally, the two-dimensional IQE value rose from 35% for the untreated sample to 66% after treatment, representing an enhancement of around 31%. These findings highlight the potential of surface engineering techniques in optimizing mc-Si for photovoltaic applications.

Surface texturing is vital in enhancing light absorption and optimizing the optoelectronic properties of multicrystalline silicon (mc-Si) samples. Texturing significantly improves light absorption by minimizing reflectance and extending the effective path length of incident light. Furthermore, porous silicon treatment on textured mc-Si surfaces offers additional advantages, including enhanced carrier generation, reduced surface recombination, and improved light emission. In this study, a dual treatment combining porous silicon and texturing was employed as an effective approach to enhance the optical and optoelectronic properties of mc-Si. Both porous silicon and texturing were achieved through a chemical etching process. After these surface modifications, the morphology and structure of mc-Si were examined using Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), UV-Vis-IR spectroscopy, Photoluminescence (PL), WCT-120 photoconductance lifetime measurements, and Internal Quantum Efficiency (IQE) analysis. Results reveal a substantial improvement in the material’s properties. The total reflectivity dropped from 35% to approximately 5%, while the effective minority carrier lifetime increased from 2 µs to 36 µs. Additionally, the two-dimensional IQE value rose from 31% for the untreated sample to 63% after treatment, representing an enhancement of around 26%. These findings highlight the potential of surface engineering techniques in optimizing mc-Si for photovoltaic applications.

In this paper, we compared the effects of alumina nanoparticles and silicon nitride layer deposited on multi-crystalline silicon separately of structure, optic, and optoelectronic properties, to achieve excellent surface. Alumina nanoparticles -covered mc-Si immersion in HF/H2O2/HNO3 and porous silicon covered with silicon nitride structure are the key factors to achieving a high electronic quality of multi-crystalline silicon. Consequently, the surface reflectivity decreases from 35% to 2% for alumina nanoparticles/PS and to 5% for silicon nitride/PS in the wavelength range of 250–1200 nm. Meanwhile, the minority carrier diffusion length increases from 2 µm to 300 µm for PS combined with SiNx and to 100 µm for alumina nanoparticles/PS. Furthermore, the Two-Dimensional Produced Current measurement shows a significant enhancement compared to bare mc-Si (2.8 nA), reaching a maximum of 34 nA for alumina nanoparticles/PS and 66 nA for PS combined with SiN. These results indicate that multi-crystalline silicon surface passivation using aluminum/PS or PS combined with SiNx is an effective approach to enhancing the electronic quality of mc-Si wafers, thereby improving the efficiency of mc-Si-based solar cells.

In this work, the impact of hydrogen plasma treatment on the electrical and electronic quality of multicrystalline silicon (mc-Si) was systematically investigated using plasma-enhanced chemical vapor deposition (PE-CVD). Hydrogen radicals generated in the plasma effectively passivate dangling bonds, reducing electrically active defects and enhancing material quality. Optimized PE-CVD conditions were applied to promote efficient hydrogen incorporation and surface modification. Optical characterization, including reflectivity measurements and FT-IR spectroscopy, confirms the formation of Si–H bonds and a significant reduction in surface reflectivity of up to 66% at 600 nm. Electrical and optoelectronic analyses reveal pronounced improvements in carrier lifetime and diffusion length, increased by 200% and 79%, respectively. In addition, dark current–voltage (I–V) measurements show a 32% decrease in series resistance and a 51% increase in shunt resistance, indicating enhanced charge transport and suppressed leakage currents. These macroscopic electrical improvements are supported by light beam-induced current (LBIC) measurements, which demonstrate a 14% increase in grain boundary current, confirming effective hydrogen passivation and reduced recombination. Overall, hydrogen plasma PE-CVD treatment is shown to significantly improve the electronic quality and photovoltaic performance of mc-Si solar cells.