Physical Review Letters
Dynamics of Si-H Vibrations in an Amorphous Environment
Marjolein van der Voort, Chris W. Rella, Lex F. G. van der Meer, Andrey V. Akimov, J. I. Dijkhuis
Abstract
We present results of the first vibrational photon-echo, transient-grating, and temperature dependent transient-bleaching experiments on a-Si:H. Using these techniques, and the infrared light of a free electron laser, the vibrational population decay and phase relaxation of the Si-H stretching mode were investigated. Careful analysis of the data indicates that the vibrational energy relaxes directly into Si-H bending modes and Si phonons, with a distribution of rates determined by the amorphous host. Conversely, the pure dephasing appears to be single exponential, and can be modeled by dephasing via two-phonon interactions.