The electrical and optical activities of small-angle grain boundaries were characterized by using electron beam induced current and cathodoluminescence. Electron beam induced current observations at room temperature indicated that the small-angle grain boundaries were grouped into two categories. Small-angle grain boundaries with misorientation angles of less than 1° had a lower electron beam . induced current contrast <10%: termed so-called general. Those with 2 to 3° angle had a contrast of more than 20%: termed so-called special. At 100K, all of the small-angle grain boundaries became visible and their contrast increased. On the other hand, cathodoluminescence observations at 15K showed that the general small-angle grain boundaries exhibited D3 and D4, while the special ones exhibited D1 and D2. These properties of the small-angle grain boundaries were explained in terms of a dislocation model. General small-angle grain boundaries were regarded as being an ensemble of individual dislocations. Special small-angle grain boundaries were composed of densely aligned dislocations in which dislocation interaction took place.

Electrical and Optical Activities of Small Angle Grain Boundaries in Multicrystalline Si. T.Sekiguchi, J.Chen, W.Lee, H.Onodera: Physica Status Solidi C, 2011, 8[4], 1347–50