Recombination kinetics of very-long-lived photoluminescence decay in a-Si:H correlated with light-induced spin densities

Abstract

We have observed photoluminescence (PL) decay persisting for more than 10⁴ s at low temperatures in hydrogenated amorphous Si (a-Si:H). The very-long-lived PL decay was identified by the third peak in the lifetime distribution using frequency-resolved spectroscopy. This residual PL decay fits the derivative of a stretched exponential function and its time integral agrees with light-induced electron spin resonance (LESR) densities. At low temperatures and low generation rates, the monomolecular distant-pair reaction dominates the recombination kinetics at extremely long times after stopping the illumination.

Acknowledgements

The authors acknowledge the Japan Private School Promotion Foundation for financial aid. They are also grateful to Professor Emeritus T. Keii for valuable comments on the stretched exponential function for monomolecular kinetics.