Effect of substrate material on LT-GaAs carrier dynamics at 800 nm

Carrier dynamics of two LT-GaAs layers grown using similar parameters, but on different substrates were studied. The behavior of the time-resolved terahertz transmission was observed to differ in trapping time constants, as well as in fluence-dependence. The differences are attributed to the difference in layer quality when using different substrates, wherein the use of silicon substrates result in increased structural defect density in the silicon substrate-grown layer, which provide additional scattering and non-recombination pathways, resulting in the reduced carrier lifetime.