Effects of oxide layer thickness on Si-nanocrystal photoluminescence intensity in Si+-implanted SiO2∕Si systems

Photoluminescence measurements are used to investigate the light emission of silicon nanocrystals prepared by Si+ implantation into SiO2∕Si layered structures. Strong variations of the luminescence intensity are observed as a function of the SiO2 thickness, for laser excitations at 405 and 488nm. These changes are associated with optical interference which produce spatial modulation of the pump laser intensity and spectral modulation of the PL emission. Model calculations using Fresnel equation solvers where the depth distribution of emitters is adjusted to minimize the difference to the measured PL intensities indicate a wider emitter profile for excitation at 405nm.