Photoluminescence Efficiency and Size Distribution of Self Assembled Ge Dots on Porous TiO2

Nelson L. Rowell (1) , David J. Lockwood (1) , Guillaume Amiard (2) , Luc Favre (2) , Antoine Ronda (2) , Isabelle Berbezier (2) , Marco Faustini (3) , David Grosso (4)

1 NRC - National Research Council of Canada
2 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
3 LCMCP (site Paris VI) - Laboratoire de Chimie de la Matière Condensée de Paris (site Paris VI)
4 LCMCP - Laboratoire de Chimie de la Matière Condensée de Paris

For Ge nanodots ∼20 nm in diameter grown by annealing a thin amorphous Ge layer deposited by molecular beam epitaxy on a mesoporous TiO2 layer on Si(001), photoluminescence (PL) was observed as a wide near-infrared band near 800 meV. Using a tight binding theoretical model, the energy-dependent PL spectrum was transformed into a dependence on dot size. The average dot size determined the peak energy of the PL band and its shape depended on the size distribution, including bandgap enlargement due to quantum confinement. Combining the dot sample PL with an established dependence of emission efficiency on dot diameter, it was possible to derive a dot size distribution and compare it with results obtained independently from atomic force microscopy.

Mots clés: Germanium Dots; Mesoporous Titanium Dioxide; Self Assembly; Size Distribution

Domaines: Matière Condensée [cond-mat]

Nelson L. Rowell, David J. Lockwood, Guillaume Amiard, Luc Favre, Antoine Ronda, et al.. Photoluminescence Efficiency and Size Distribution of Self Assembled Ge Dots on Porous TiO2. Journal of Nanoscience and Nanotechnology, 2011, 11 (10), pp.9190--9195. ⟨10.1166/jnn.2011.4311⟩. ⟨hal-01811421⟩