Photoluminescence spectra from Si impurity centers, in films that had been grown by means of chemical vapor deposition, were studied at temperatures of between 9 and 300K. Laser excitation at 514.5nm, and resonance with the zero-phonon absorption line at 737nm (1.6823eV) were used. The luminescence lines narrowed at resonance excitation, and the vibrational structure of the Si center was observed with a major phonon replica at 767nm (1.6165eV). The observed vibrational energy of 515/cm supported a diatomic quasi-molecular Si2 center structure.

A.A.Gorokhovsky, A.V.Turukhin, R.R.Alfano, W.Phillips: Applied Physics Letters, 1995, 66[1], 43-5