Carrier dynamics in porous silicon studied with a near-field heterodyne transient grating method

The dynamics of excited carriers in porous silicon were investigated using the near-field heterodyne transient grating method, and the fundamental processes related to light emission were determined. The processes include trapping to surface states and two-body recombination of excited carriers, with trapping being the dominant source of light emission. Since nonlinear processes, namely two-body recombination, are included, it is necessary to measure the pump intensity dependence of the transient responses and to analyze them with a nonlinear differential equation in order to obtain accurate decay times.

Near-field heterodyne transient grating method was applied for dynamics measurement of excited carriers in porous silicon, and the fundamental processes related to light emission are considered. The processes include trapping to surface states and two-body recombination of excited carriers, and the former process is the dominant source of light emission.