Relative External Quantum Efficiency of Crystalline Silicon Wafers From Photoluminescence

The external quantum efficiency is routinely measured to determine the carrier collection probability of solar cells as a function of illumination wavelength. The common method used to perform these measurements requires a fully metalized device such that the short circuit current can be measured under monochromatic illumination. This paper demonstrates the extraction of relative external quantum efficiency data from open circuit photoluminescence measurements in a contactless fashion. Good agreement is observed between the photoluminescence-based technique and traditional external quantum efficiency data for illumination wavelengths in the range 400 to 625 nm. Deviations are observed for longer illumination wavelengths and their origin is discussed.