| The electronic effects of hydrocarbon plasma annealing on the grain boundaries of large-grained, p-type Wacker-Silso cast polycrystalline silicon samples have been investigated. The investigations included measurements of photoconductance and decay time on individual grain boundaries, as well as electrical resistivity and Hall mobility on the total specimen. It has been found that hydrocarbon (methane or ethane) annealing significantly reduces the grain boundary barrier heights, substantially increases the minority carrier decay times (and hence lifetimes), significantly reduces resistivity and activation energies, minority capture cross-sections, and the trap density of states; and enhances Hall mobilities. Hydrocarbon plasma annealing may prove useful for passivation of grain boundaries in polycrystalline solar cells and other devices.; Relations connecting photoconductivity of a grain boundary with bias voltage, illumination intensity and temperature are suggested. |
