Dispersive photoluminescence decay by geminate recombination in amorphous semiconductors
Dispersive photoluminescence decay by geminate recombination in amorphous semiconductors
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DOI:
10.1103/physrevb.71.235212
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发表时间:
2005-04
影响因子:
3.7
通讯作者:
K. Seki;K. Murayama;M. Tachiya
中科院分区:
文献类型:
--
作者:
K. Seki;K. Murayama;M. Tachiya
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, $delta sim 1.2-1.3$, 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.