Interpretation of the temperature dependence of the luminescence intensity, lifetime, and decay profiles in porous Si

The temperature dependences of the luminescence intensity, lifetime, and decay profiles for porous Si are studied from 5 to 271 K. The radiative decay rates were determined from the tails of the decay curves and found to have an activation-type temperature dependence above 10 K. To describe the nonradiative process we propose a model in which we assume a tunneling and a thermally activated escape of the photoexcited carriers through barriers with a Gaussian distribution in height. The temperature dependence of intensity, lifetime, and nonexponential decay profiles are successfully interpreted in terms of this model.