Optical and Electrical Characterization of Er/Yb‐Doped Porous Silicon for Advanced Photovoltaic Applications

This study examines the optical and electrical properties of erbium‐ and ytterbium‐doped porous silicon (PS). Reflectance, absorbance, and impedance measurements reveal that doping with 0.005 M Er(NO 3 ) 3 and Yb(NO 3 ) 3 significantly enhances absorbance, with Yb achieving a 225% increase compared to undoped PS. Thermal oxidation further boosts absorbance by up to 300% in the near‐infrared (NIR) region, attributed to the formation of Er 2 Si 2 O 7 , Er 2 SiO 5 , and Yb 2 Si 2 O 7 confirmed by energy dispersive X‐ray spectroscopy and X‐ray diffraction. Despite these changes, Kubelka–Munk analysis shows no significant bandgap alteration for indirect transitions. The improved optical absorption, particularly in the NIR, suggests potential for enhancing photovoltaic device efficiency. Electrically, impedance spectroscopy indicates that Er/Yb doping improves charge transfer in liquid media, though the ternary compounds reduce layer conductivity. These findings demonstrate that rare earth doping enhances both optical and electrical properties of PS, making it promising for optoelectronic applications, especially in NIR‐sensitive photovoltaics.