Structure-Dependent Vibrational Lifetimes of Hydrogen in Silicon

The lifetimes of the Si-H vibrational stretch modes of the [Formula presented] ([Formula presented]) and [Formula presented] ([Formula presented]) defects in crystalline Si are measured directly by transient bleaching spectroscopy from 10 K to room temperature. The interstitial-type defect [Formula presented] has a lifetime of 4.2 ps at 10 K, whereas the lifetime of the vacancy-type complex [Formula presented] is 2 orders of magnitude longer, 295 ps. The temperature dependence of the lifetime of [Formula presented] is governed by TA phonons, while [Formula presented] is governed by LA phonons. This behavior is attributed to the distinctly different local structure of these defects and the accompanying local vibrational modes.