The formation of dendrites in overtreated CdSeTe/CdTe solar cells

Aggressive cadmium chloride activation conditions (>450°C) used to activate a FTO/CdSeTe/CdTe device in an oxygen enviroment results in the formation of dendrites at the front and back of the device. Most of the dendrite formation occurs at the front interface (FTO/CdSeTe). Optical Microscopy and X-Ray Photoelectron Spectroscopy (XPS) have been used to study the dendrite morphology and chemical composition. Optical images revealed that the dendrites can grow >500µm in length causing a range of discolourations from oxidation (dark brown/pink). The XPS analysis provides evidence for the presence of cadmium oxychlorides.