ABSTRACT
Edge-defined film-fed growth (EFG) is an economical method of producing multi-crystalline silicon ribbon for solar cells. Scanning cathodoluminescence (CL) studies of electron-irradiated EFG silicon show that the dominant line in the luminescence spectrum is the G-line. EFG silicon is heavily doped with carbon from the graphite crucible and die. The CL studies were performed in a scanning electron microscope equipped with a MonoCL3 CL system and infrared detection. At temperatures below 20 K, the CL image showed uniform luminescence except at grain boundaries and surface defects, where competing non-radiative recombination mechanisms were operating. The temperature change in luminescence behaviour is very close to the temperature at which thermal ionisation of excitons begins to take place. An economical method of growing silicon for solar cell production is to produce it in the form of a ribbon, thereby avoiding the cost and wastage involved in slicing a boule.
