Temperature-dependent lifetime distribution of the photoluminescence S-band in porous silicon

Abstract

We study the recombination mechanism of the visible photoluminescence (PL) S-band in p-doped porous Si layers by time-resolved photoluminescence. From the observed ‘‘stretched-exponential’’ PL decays we present a simple yet accurate evaluation method for lifetime distributions G(τ) and average recombination lifetimes 〈τ〉. The average lifetimes feature a strong temperature dependence and a characteristic thermal activation energy of 10–20 meV for low temperatures. Our results are discussed within the models of quantum-confined exciton recombination and surface state recombination.