Visible photoluminescence of Ge dots embedded in Si/SiO2 matrices
A. A. ShklyaevMasakazu IchikawaJoint Research Center for Atom Technology (JRCAT), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-0046, Japan and Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-Tokyo 113-8656, Japan
2002en
ABI
Abstract
Ge island formation on ultrathin SiO2 films enabled us to fabricate multilayer structures of Ge dots ∼6–7 nm in diameter and with an extremely high dot density of 2×1012 cm−2. Each dot had a boundary with the SiO2 film and a Si spacer layer. The multilayer structures exhibited photoluminescence (PL) with a maximum in the range of 2–3 eV depending on the excitation energy. The PL was associated with recombination between holes confined within Ge dots and electrons localized in the radiative defect centers at the Ge-dot/SiO2 interfaces. The results suggest that this recombination is much more effective than that at the Si/SiO2 interface and supported by the hole migration from the Si spacer layers to the Ge dots.
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