Ultrafast response of SiC and Si nanocomposite material systems

Ultrafast responses are analysed for semiconductor-polymer nanocomposite (NC) material systems with SiC and Si nanoparticles embedded in a polymer host. A dynamical model is developed to link photoexcitation, diffusion and surface recombination effects to the charge carrier lifetime. The modelled responses are contrasted with ultrafast differential transmission measurements for both SiC and Si material systems, with excellent agreement. The respective SiC and Si NC charge carrier lifetimes of 4.5 and 12 ps are found to be dominated by surface recombination effects and are far shorter than their 22 μs and 20 ns bulk semiconductor counterparts.