Monte-Carlo simulations of the recombination dynamics in porous silicon

H. Eduardo Roman; Lorenzo Pavesi

doi:10.1088/0953-8984/8/28/003

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Monte-Carlo simulations of the recombination dynamics in porous silicon

H. Eduardo Roman·Lorenzo Pavesi

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Abstract

A simple lattice model describing the recombination dynamics in visible light emitting porous Silicon is presented. In the model, each occupied lattice site represents a Si crystal of nanometer size. The disordered structure of porous Silicon is modeled by modified random percolation networks in two and three dimensions. Both correlated (excitons) and uncorrelated electron-hole pairs have been studied. Radiative and non-radiative processes as well as hopping between nearest neighbor occupied sites are taken into account. By means of extensive Monte-Carlo simulations, we show that the recombination dynamics in porous Silicon is due to a dispersive diffusion of excitons in a disordered arrangement of interconnected Si quantum dots. The simulated luminescence decay for the excitons shows a stretched exponential lineshape while for uncorrelated electron-hole pairs a power law decay is suggested. Our results successfully account for the recombination dynamics recently observed in the experiments. The present model is a prototype for a larger class of models describing diffusion of particles in a complex disordered system.

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H. Eduardo Roman, Lorenzo Pavesi. 1995-05-09. Monte-Carlo simulations of the recombination dynamics in porous silicon. https://doi.org/10.1088/0953-8984%2F8%2F28%2F003

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