Extended spectral response analysis of conventional and front surface field solar cells

•Three distinct regions in plot of inverse-IQE versus absorption length.•Refined technique accommodating both conventional and front surface field devices.•Newly discovered blue region revealing front surface properties.•Opposite slope of red to infrared region in front surface field device.•More simplified infrared analysis by physical reasoning.

Historically, spectral analysis of internal quantum efficiency has played an important role in solar cell characterization. The applicability of this technique is reassessed in view of developments over recent years as a means of determining cell optical and electrical properties. The refined technique, applicable to both conventional and front surface field devices, highlights three distinct spectral regions, allowing additional front surface investigation by blue response analysis and more simplified analysis over a weakly absorbed region where photo-generation is uniform throughout the absorber and parasitic absorption remains sufficiently constant at these wavelengths. The approach is demonstrated by application to a modern front surface field device as a complement to previous work.