Recombination and charge transport in polycrystalline semiconductors under the action of optical radiation

A new theory is proposed for recombination and charge transport in polycrystalline semiconductors exposed to optical radiation. Relations are derived for the height of the intercrystallite potential barriers (Vs), the recombination current density at grain boundaries (jR), the effective lifetime of minority carriers (τp), and the conductivity (σ) as a function of the level of photoexcitation (G) of the polycrystal. The relations are valid for any value of Lb/d, where Lb is the diffusion length of minority carriers in the volume of the grains in the polycrystal, and d is the grain size. Plots of Vs, jR, τp, and σ versus G and d in polycrystalline silicon are presented