Explanation of the large spin-dependent recombination effect in semiconductors

Abstract

Previous theories to explain the variation of photoconductivity upon saturation of electron spin resonance, as observed by Lépine in silicon, predict an effect 10 to 100 times smaller than experiment. In the present model we show that, due to the shorter lifetime of electron-hole pairs in singlet configuration, the steady state spin distribution shows a surplus of triplet pairs. Saturation of resonance restores the random distribution, resulting in a shortening of the recombination time. The relative variation can be as large as 10 %, and is field independent as confirmed by experiment.