J. Bellessa et al., QUANTUM-SIZE EFFECTS ON RADIATIVE LIFETIMES AND RELAXATION OF EXCITONS IN SEMICONDUCTOR NANOSTRUCTURES, Physical review. B, Condensed matter, 58(15), 1998, pp. 9933-9940
A systematic study of exciton dynamics is presented in quantum boxes f
ormed naturally along the axis of a V-shaped quantum wire, by means of
time and spatially resolved resonant photoluminescence. The dependenc
e of radiative Lifetimes and relaxation mechanisms of excitons is dete
rmined versus the size of the boxes. The radiative recombination rate
varies linearly with the length of the box, showing that the exciton h
as a coherence volume equal to the volume of the box. In a low excitat
ion regime, emission from excited states has not been observed, which
would be a consequence of relaxation bottleneck, but there is clear ev
idence that relaxation via emission of LBL phonons depends strongly on
the energy separation between the different quantum box levels. [S016
3-1829(98)07839-4].