title: Emission efficiency limit of Si nanocrystals.
abstract: One of the important obstacles on the way to application of Si nanocrystals for development of practical devices is their typically low emissivity. In this study we explore the limits of external quantum yield of photoluminescence of solid-state dispersions of Si nanocrystals in SiO2. By making use of a low-temperature hydrogen passivation treatment we demonstrate a maximum emission quantum efficiency of approximately 35%. This is the highest value ever reported for this type of material. By cross-correlating PL lifetime with EQE values, we obtain a comprehensive understanding of the efficiency limiting processes induced by Pb-defects. We establish that the observed record efficiency corresponds to an interface density of Pb-centers of 1.3 × 10(12) cm(12), which is 2 orders of magnitude higher than for the best Si/SiO2 interface. This result implies that Si nanocrystals with up to 100% emission efficiency are feasible.
authors.affiliation: Van der Waals-Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
authors.forename: Rens
authors.initials: R
authors.lastname: Limpens
authors.affiliation: ECN Solar Energy, PO Box 1, 1755 ZG Petten, The Netherlands.
authors.forename: Stefan L
authors.initials: SL
authors.lastname: Luxembourg
authors.affiliation: ECN Solar Energy, PO Box 1, 1755 ZG Petten, The Netherlands.|Photovoltaic Materials and Devices, Delft University of Technology, 2600 GA Delft, The Netherlands.
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Weeber
authors.affiliation: Van der Waals-Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, The Netherlands.
authors.forename: Tom
authors.initials: T
authors.lastname: Gregorkiewicz