Porous silicon studied with time-resolved photoluminescence

Porous silicon has been studied with time-resolved photoluminescence, and growth as well as decay curves have been measured at several detection energies, with sample temperatures between 10 and 300 K. In the decay curves, three components are mainly observed, a small one which is very fast, with time scales of the order of nanoseconds or faster, the main component having time scales of the order of milliseconds, and a very small, very slow component, with time scales of the order of seconds. The main components can in most - but not all - cases be fitted well with stretched exponentials containing two fitting parameters. Of these, it comes out that the parameter accounting for disorder or the like depends only little upon detection energy and temperature, whereas the parameter accounting for the development in time decreases substantially for increasing temperature. The results are discussed.