H-sensitive radiative recombination path in Si nanoclusters embedded in SiO2

Abstract

The room-temperature photoluminescence (PL) from silicon nanocrystals embedded in a SiO2 matrix fabricated by electron cyclotron resonance plasma-enhanced chemical vapor deposition and subsequent annealing in Ar and (Ar+5%H2) was studied. In addition to strong increases of the integrated PL intensity (factors of ∼4 to 10), the selective enhancement of contributions to the PL spectra at long wavelengths was observed for (Ar+5%H2) annealings. The selective H passivation of Si dangling bonds in disordered Si nanoclusters where radiative recombination proceeds through disorder-induced shallow states is proposed as a possible explanation for the observed effects. The authors gratefully acknowledge Professor W. Lennard for Rutherford backscattering measurements, J. Wojcik and E.A. Irving for growing the SRSO samples, M. Flynn and T. Roschuk for fruitful discussions, G. Pearson for assistance with the XRD measurements, and J. Garrett for help with the annealing furnace. This work has been funded by the Ontario Research and Development Challenge Fund (ORDCF) under the Ontario Photonics Consortium (OPC) and by Ontario Centres of Excellence (OCE) Inc.