High-performance Si microwire photovoltaics

Crystalline Si wires, grown by the vapor-liquid-solid (VLS) process, have emerged as promising candidate materials for low-cost, thin-film photovoltaics. Here, we demonstrate VLS-grown Si microwires that have suitable electrical properties for high-performance photovoltaic applications, including long minority-carrier diffusion lengths (Ln [dbl greater-than] 30 [small micro]m) and low surface recombination velocities (S [double less-than] 70 cm[middle dot]s-1). Single-wire radial p-n junction solar cells were fabricated with amorphous silicon and silicon nitride surface coatings, achieving up to 9.0% apparent photovoltaic efficiency, and exhibiting up to [similar]600 mV open-circuit voltage with over 80% fill factor. Projective single-wire measurements and optoelectronic simulations suggest that large-area Si wire-array solar cells have the potential to exceed 17% energy-conversion efficiency, offering a promising route toward cost-effective crystalline Si photovoltaics.