Vacancy-hydrogen defects in silicon studied by Raman spectroscopy

A Raman study of hydrogen stretching modes in vacancy-hydrogen defects (VHn, n = 1,2,3,4) is presented. The positions of the vibrational modes are compared to recent IR absorption results. The Raman lines exhibit pronounced polarization due to the [111] orientation of the silicon-hydrogen bend. Based on the defect symmetry derived from the polarization-dependent Raman signals and the Raman intensities we assign the Raman lines to the defects VH4: 2234 cm(-1)(A(1) mode), 2205 cm(-1) (T-2 mode); V2H6: 2180 cm(-1) (A(1g), mode), 2155 cm(-1) (E-g mode). We tentatively attribute the 2120- and 2099-cm(-1) lines to VH2 and the 2022-cm(-1) line to VH.