Low-loss photon-to-electron conversion

Silicon photodiodes with induced junction structure can reach low-loss photon-to-electron conversion. The calculated conversion efficiency in the visible wavelength range typically deviates less than 10 ppm from unity and its uncertainty is about 100 ppm at room temperature or as low as 1 ppm at 78 K. Here we show experimentally that our dedicated induced junction photodiodes indeed have very low conversion losses when they are assembled in a light trapping structure as provided by, for example, the predictable quantum efficient detector (PQED). It is concluded that the remaining measured losses, if any, are probably due to surface recombination of electrons and holes close to the silicon/silicon dioxide interface of the photodiode.