Dispersive photoluminescence decay by geminate recombination in amorphous semiconductors

Abstract

The photoluminescence decay in amorphous semiconductors is described by power law $t^{-delta}$ at long times. The power-law decay of photoluminescence at long times is commonly observed but recent experiments have revealed that the exponent, $deltasim1.2-1.3$, is smaller than the value 1.5 predicted from a geminate recombination model assuming normal diffusion. Transient currents observed in the time-of-flight experiments are highly dispersive characterized by the disorder parameter $alpha$ smaller than 1. Geminate recombination rate should be influenced by the dispersive transport of charge carriers. In this paper we derive the simple relation, $delta=1+alpha/2$. Not only the exponent but also the amplitude of the decay calculated in this study is consistent with measured photoluminescence in a-Si:H.

arXiv comment18pages. Submitted for the publication in Phys. Rev. B

References in corpus (1)

• Fractional Reaction-Diffusion Equation

Cited by in corpus (4)

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