Anomalous photoluminescence behavior from amorphous Ge quantum dots produced by buffer-layer-assisted growth

摘要

The authors present photoluminescence results from amorphous Ge quantum dots formed using buffer-layer-assisted growth. Their sizes, shapes, and densities were controlled by varying the thickness of the Xe buffer layer, with sizes varying from 2 to 8 nm. A relatively weak signal was observed at ～3 K at ～0.91 eV that was independent of size and was insensitive to laser intensity. Its temperature-dependent magnitude showed a Berthelot-type behavior that they associate with hopping of carriers between radiative tail states and shallow nonradiative states. These findings are similar to those from porous semiconductors.