Phonon wind on excitons in silicon

✍ Scribed by A.V. Akimov; A.A. Kaplyanskii; E.S. Moskalenko

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 529 KB
• Volume: 169
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(91)90255-d

✦ Synopsis

The invited talk was given by A.V. Akimov.

We ohservcd experimentally the strong effect of nonequilibrium phonons on the intensity of the luminesccncc of free and bound cxcitons, created by optical illumination of a Si surface immersed in liquid helium (7'= I .8 K). The polarity of the phonon-induced luminescence signal strongly depends on the perfection of the surface. Two factors were included in the theoretical explanation of this effect: (1) the phonon-induced dissociation of hound excitons. and (2) the drag of fret cxcitons by phonon fux (phonon-wind effect) vvhich shifts the exciton cloud to the surface, where exciton recombination is strong. This effect is used to study spectral features of phonon propagation in Si and a-Si: H films.