INTERPRETATION OF THE TEMPERATURE-DEPENDENCE OF THE LUMINESCENCE INTENSITY, LIFETIME, AND DECAY PROFILES IN POROUS SI

The temperature dependences of the luminescence intensity, lifetime, a nd decay profiles for porous Si are studied from 5 to 271 K. The radia tive decay rates were determined from the tails of the decay curves an d found to have an activation-type temperature dependence above 10 K. To describe the non-radiative process we propose a model in which we a ssume 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 dec ay profiles are successfully interpreted in terms of this model.