Temperature-induced crossover between bright and dark exciton emission in silicon nanoparticles

In: European Physics Letters, Jg. 79 (2007) ; Nr. 3, S. 37002 (5pp)
ISSN: 0295-5075, 1286-4854
Zeitschriftenaufsatz / Fach: Maschinenbau; Physik
Fakultät für Physik » Experimentalphysik
The excitonic fine structure of silicon nanoparticles is investigated by time-resolved and magnetic-field–dependent photoluminescence. The results are analyzed using the common model of an excitonic fine structure consisting of a bright and a dark exciton. We find that the radiative recombination rates of both excitons differ only by a factor of eight. Therefore, we observe a thermal crossover in the character of the emission from bright-exciton-like to dark-exciton-like. The validity of our model is further supported by magnetic-field–dependent measurements, in which effects of state mixing are observed.