Slow transient recombination phenomenon in mono-crystalline silicon

Boron diffusion has been shown in previous studies to reduce the bulk carrier lifetime of high resistivity silicon. Investigation into the optimal boron diffusion conditions for solar cell processing has lead to the discovery of a slow light induced transient phenomenon in 50 and 1000-5000 Ωcm p-type float zone wafers. The bulk carrier lifetime increases and the emitter recombination current density decreases during the first few minutes of exposure to standard 1-sun intensity light. This improvement in the electronic properties with illumination has previously been inferred from measurements in completed solar cells and is measured quantitatively here