Carrier recombination in silicon quantum wires surrounded by dielectric medium

Non-equilibrium carrier dynamics in silicon quantum wires is theoretically investigated taking into account the existence of two coupled subsystems: f ree carriers and excitons. The filling of space among the wires by dielectr ic medium results in the decrease in binding energy of excitons and thus th eir concentration and at the same time in the increase in free carrier conc entration. Modification of the relation between the exciton concentration a nd free carrier density changes the relaxation time of nonequilibrium carri ers. The model is experimentally proved using the time-resolved methods of photoluminescence and IR free carrier absorption in porous silicon.