Mechanisms of luminescence in silicon photovoltaics

A measured luminescence spectrum is a complex combination of numerous phenomena occurring in both silicon wafers and measurement equipment. The emitted spectrum itself is determined by the intrinsic properties of silicon, defects and impurities in the host material, experimental conditions, and surface optics. The detected spectrum is then affected by the spectral responses of the luminescence spectroscopy/imaging system. However, by systematically controlling and monitoring the parameters which can potentially affect the detected spectra, certain properties of silicon wafers and solar cells can be evaluated. This paper reviews some basic mechanisms of luminescence phenomena in silicon wafers and solar cells. This is essential for understanding the rich information embedded in the captured PL spectra, based on which various applications in silicon photovoltaics can be established.